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Ginger (Zingiber officinale Rosc.) and turmeric (Curcuma longa L.) rhizomes are globally consumed as medicinal spices and their production can be enhanced by tillage practices. However, there is no information worldwide on how harvesting of ginger and turmeric crops from tilled fields can contribute to soil degradation, particularly soil loss due to crop harvest (SLCH crop). Thus, a 2-year field study was conducted with three tillage practices: zero tillage (ZT), traditional tillage (TT), and minimum tillage (MT) to compare soil transported by ginger and turmeric harvesting under the tillage management system. The harvested rhizomes of ginger and turmeric were separately washed to remove adhering soils (transported soil). Soil transported by ginger (2.45 Mg ha−1harvest−1) was eight times higher than that by turmeric (0.30 Mg ha−1 harvest−1) regardless of tillage practice due to higher numbers of rhizomatous hairs and rhizome yields associated with ginger. Overall, ginger was higher than turmeric by factors of 9.5 for rhizomatous hair weight and 3.7 for crop yield. SLCH crop was highest in MT (2.50 Mg ha−1 harvest−1) followed by TT (1.20 Mg ha−1 harvest−1) and least in ZT (0.42 Mg ha−1 harvest−1). Generally, tillage practices increased soil loss by creating a conducive soil environment for the growth and development of rhizomatous hair weight (R2 = 0.24 – 0.92; P <0.05) and crop yield (R2 = 0.86 – 0.95; P <0.05) which were linearly related to soil transportation. Soil denudation rate (soil degradation) due to ginger (0.025 mm yr−1) harvesting was eight times higher than that due to turmeric (0.003 mm yr−1). Rhizomatous hair numbers, rhizome yields and soil management increased soil transportation by ginger and turmeric differently under traditional agriculture. Soil loss by ginger validates the need to conduct further tillage studies under wider textural classes. • Tillage and rhizome morphologies jointly increased soil loss due to crop harvesting. • Soil transported during ginger harvest was eight times higher than that by turmeric. • Rhizome morphology determined soil loss during ginger harvest. • Soil properties largely controlled soil loss during turmeric harvest. [ABSTRACT FROM AUTHOR]

Organic materials are integral to the soil carbon cycle in agricultural ecosystems, yet their specific impacts on soil organic carbon (SOC) and microbial diversity are not fully understood. In this study, we analyzed 188 data pairs from 57 published papers to assess the effects of various organic materials on SOC composition and microbial diversity across different farmlands. Our findings indicate that the addition of organic materials consistently enhances SOC composition and promotes both bacterial and fungal diversity. Notably, the particulate organic carbon (POC) fraction exhibited the most significant increase (42.35%), suggesting that POC is the primary pathway for organic carbon accumulation. Our analysis also identified the type of organic material as the leading factor influencing soil active carbon fractions and microbial diversity, with compost emerging as the most effective material for boosting soil carbon sequestration and microbial richness. Interestingly, while both dissolved organic carbon (DOC) and microbial biomass carbon (MBC) increased with organic material addition, a negative correlation between these two components was observed. This study advances our understanding of the complex interactions between organic materials, SOC components, and microbial diversity, providing valuable insights for the development of sustainable soil management practices aimed at enhancing soil carbon storage and agroecosystem health. [Display omitted] • Organic material enhanced active SOC components and microbial diversity. • Material type is a key determinant of soil carbon composition. • The main factor of SOC increase was the accumulation of POC. • MBC has a potential competition with DOC. [ABSTRACT FROM AUTHOR]

Tillage is an essential practice for soil preparation in agriculture that influences a broad variety of soil parameters. However, the long-term implications of tillage on soil health are complex, context specific, and need to be better understood. The aim of our study is to evaluate soil physical, chemical, and biological effects of three different tillage practices: conventional tillage (CT), mulch tillage (MT), and no-till (NT). A long-term experiment in Mistelbach, Lower Austria, was launched in 1994 and comprehensively sampled in 2002 and 2021. To evaluate tillage-impacts over the two decadal monitoring we assessed soil health indicators in the 0–20 cm soil depth (conventional ploughing layer) and below 20 cm. A "Soil Management Assessment Framework" (SMAF) procedure was applied to assess and compare soil quality using the Soil Quality Index (SQI). Considering multiple indicators, we found overall quality improvements in all three tillage-experiments over time. However, particularly the conservation practices (MT and NT) enhanced soil quality, predominately soil organic carbon (SOC) and soil physical indicators (e.g. water holding capacity, coarse pores). The study confirms that SOC in the 0–20 cm layer significantly increased under no-till (46 Mg C ha−1) compared to conventional tillage (26 Mg C ha−1). At the same time aggregate stability and water holding capacity increased under conservation agriculture (MT and NT). The proven positive impacts on soil health will further help to promote agricultural practices that sustain productivity while pushing forward climate change mitigation actions in temperate climate. • Mulch and no-tillage significantly enhanced soil quality over two decades. • Soil organic carbon increased under mulch and no-tillage in the upper soil horizon. • Soil Quality Index provides a holistic overview of long-term tillage impacts. [ABSTRACT FROM AUTHOR]

Sustainable soil management is indispensable for achieving the UN Sustainable Development goals and soil carbon sequestration for climate change mitigation has gained importance in recent years, yet there are few examples of projects carried out to this purpose, and protocols that facilitate this task. Here we present a monitoring system that relies on sampling soils in the field, as opposed to a modeling approach. The high spatial variability of SOC was addressed by requiring that the participating farms divide their land according to management zones, based on soil type, slope position and land use history, and the sampling density was established as one sampling point per one hundred hectares, while for environments smaller than 500 ha minimum of five points must be used. These points are georeferenced and will be revisited for annual monitoring of sustainable soil management, and every five years for soil sampling for SOC, texture, bulk density, pH, electric conductivity (if indicated), and available phosphorus determinations. The monitoring of sustainable soil management will be carried out through a visual evaluation of 12 soil quality parameters, as described in the handbook published by the AGSUS group. The data obtained from the visual evaluation and the soil analyses (bulk density, particle size fractions, C content, and pH) in the baseline monitoring of Argentinean and Brazilian farms during 2022 were analyzed for the relation between visual evaluation score and the means of these soil parameters. The organic matter indicator (OMI)was calculated by the formula OMI = OM/clay plus silt*100. The data base contained visual soil evaluation scores at 80 georeferenced sampling points, representing 12 farms located in different agroecological zones of the Argentinean Pampas, and 47 sampling points on two farms in Mato Grosso, Brazil. Our results showed a relationship between the VE (Visual Evaluation) score and SOC contents of the soils, especially when these were expressed in relation to their fine mineral particles as with the OMI for the soils of the Argentinean Pampa and the Brazilian Mato Grosso. The OMI showed differences between the three VE scores ranging from 4.7 to 6.7 and from 3.1 to 5.1 in the 0–0.1 m and 0.1–0.2 m depths, respectively. Relationships between the VE score and SOC, OMI, Sand, Silt and Clay plus Silt were only found for the 39 cases of VE "moderate" score in Pampas soils, whereas for the 39 cases of "good" scores no significant relations were encountered. These soils had high SOC and OMI, indicating that they are healthy soils, near saturation level, with low C sequestration potential. • A monitoring and sampling protocol for carbon sequestration project is presented. • Protocol includes on-site soil sampling and visual evaluation of soil health. • Results of on-going projects indicate good agreement between visual evaluation and soil carbon data. • Organic matter indicator suggests that some sites are near carbon saturation. [ABSTRACT FROM AUTHOR]

Increasing crop diversity and nitrogen (N) fertilizer application have been identified as effective strategies for enhancing productivity and soil organic carbon (SOC) storage in agroecosystems. However, the impact of these management practices on soil inorganic carbon (SIC) in agroecosystems remains unclear. At present, we evaluated the effects of maize/faba bean intercropping, N application rates, and inoculation rhizobia of faba bean on SIC in the top 20 cm of soil depth using a 13-year crop diversity field experiment. Our results showed that the soil total carbon (TC) content increased significantly by 5.9 % and 7.0 % compared to faba bean monoculture and maize monoculture, respectively, after 13 years of continuous intercropping. Intercropping increased the pedogenic carbonate (PIC) content by 36.7 %, resulting in an 8.9 % higher SIC content compared to faba bean monoculture. Additionally, intercropping significantly reduced the dissolution of lithogenic carbonate (LIC) by 17.5 %, leading to a 7.6 % higher SIC content compared to maize monoculture. The formation of PIC was associated with an increase in soil available cations especially Ca2+ in intercropping. The conservation of LIC was related to the higher soil available Mg2+ in intercropping than monoculture. Faba bean inoculated with rhizobia significantly decreased SIC content due to soil acidification after 13 years of continuous cropping. Intercropping also significantly increased SOC and C3-derived SOC content compared to maize monoculture and increased C4-derived SOC content compared with faba bean monoculture. Soil organic carbon showed a positive correlation with SIC across all cropping systems, and the SOC fractions could affect the neoformation of PIC and dissolution of LIC. Our results demonstrate that intercropping can increase SIC content, which further promotes soil carbon sequestration. This study highlights the significance of increasing crop diversity on cropland carbon sequestration and provides practical implications for mitigating carbon emissions. • Long-term intercropping increased soil total carbon and inorganic carbon content. • Intercropping improved soil pedogenic and lithogenic carbonate content. • Soil organic carbon fractions affected pedogenic and lithogenic carbonate dynamics. • Inoculation rhizobia of faba bean decreased soil inorganic carbon content. [ABSTRACT FROM AUTHOR]

Management of agricultural soils for increased productivity may exert positive or negative effects on soil structure, functions, and organic carbon (SOC) stocks. In this study, a field experiment established in 1993 on a clayey soil in southwest Finland was revisited to investigate the long-term effects of deep ploughing and liming on SOC concentration and stock, particulate (POC) and mineral-associated (MOC) fractions of SOC, pH, electrical conductivity (EC), bulk density (BD), porosity, critical pore size and cereal yield. The experiment comprised whole plots of conventional tillage (CT) to a maximum depth of ca. 20 cm, and plots deep ploughed to ca. 35 cm depth by a commercial (DP1) or by a self-made (DP2) plough. The tillage plots were divided into three split-plots assigned to liming treatments (low, medium and high). Three decades after implementation, the increasing liming rates still induced consistent differences in soil pH, a significant increasing effect on total porosity in the subsoil, and a marginally significant decrease in yield with an increase in soil acidity. The deep ploughing exerted a minor difference in topsoil texture, slightly lowered SOC concentration in the topsoil in DP2 in comparison to CT, and slightly higher subsoil SOC concentration in DP1 in comparison to CT, which indicated transfer of the topsoil SOC to deeper layers and dilution of the SOC in the new topsoil. However, no significant differences between the tillage treatments occurred in SOC stocks. In MOC and POC concentrations, there were no significant differences between the control and tillage treatments. The effects of deep ploughing on soil structural properties on the decadal time scale were minor and scattered. Cereal yield exhibited a slight negative trend for deep ploughing. For EC and BD, no treatment effects were recorded. Overall, the study showed that the legacy of soil management effects on soil properties can be persistent on decadal time scales, but no permanent structural damage due to deep ploughing nor gains in SOC stock accrual could be observed. • Effects of deep ploughing and liming were studied three decades after treatments. • No significant differences in SOC storages between the tillage treatments were found. • Deep ploughing had only minor effects on soil structure both in topsoil and subsoil. • Liming rates consistently induced differences in soil pH three decades after treatment. [ABSTRACT FROM AUTHOR]

Healthy soils provide critical ecosystem services, addressing modern societal challenges such as human health safeguarding, food security, climate change adaptation, etc. Unfortunately, 60–70 % of soils in the European Union (EU) are in an unhealthy state, due to various natural and socio-economic factors. Degradation is the most severe threat, impairing soil quality, hindering the full delivery of its functions, jeopardizing its productivity, and constituting a monetary hazard. This is why the European Commission (EC) has put soil health at the epicenter of several EU policies, in different, yet inter-connected domains (e.g., agriculture, climate, etc.). Soil governance has gained increasing interest over the years, with the Common Agricultural Policy (CAP) and the European Green Deal (EGD) being frontrunners in the attempt to achieve climatic neutrality, zero pollution, and sustainable food provision. These times call for a holistic revision of our production systems, consumption patterns, and the management of soil. However, a significant gap between soil conservation science and practice raises concerns about the effectiveness of soil-related policies. With a focus on soil erosion, this review provides an overview of such policies and how they promote soil restoration and preservation, underlining in parallel the importance of public awareness and participatory engagement in achieving their objectives. • An overview of soil-related policies and missions in the EU is presented. • There is a particular (but not exclusive) focus on soil erosion. • The importance of public awareness and participatory engagement is underlined. • Barriers that hinder policy effectiveness and potential contingencies are analyzed. [ABSTRACT FROM AUTHOR]

This study evaluates the temporal stability of X-ray fluorescence (XRF) models for predicting plant-available calcium (av-Ca) and potassium (av-K) in a tropical agricultural field under changing soil management. Understanding this stability is crucial for advancing XRF as a quick and clean tool for soil nutrient monitoring. XRF models were tested across six sampling periods (2015, 2019, 2020, and three in 2022); lime and potash rock powder were applied before 2022 samplings to assess the XRF models response to amendments, which altered the ratio of total to plant-available nutrients (T/A ratio). We evaluated a simple model (M15) calibrated using only samples acquired in 2015 (S15), and two time-specific models (M15+SS and SS models) that incorporate samples collected at each analysis period. All models showed temporal stability when the T/A ratio was consistent, with RMSE values of 3.15─6.95 mmol c dm−3 (1.91 ≤ RPIQ ≤ 4.22) for av-Ca and 1.20─1.64 mmol c dm−3 (1.86 ≤ RPIQ ≤ 2.55) for av-K. However, the application of lime and potash rock powder disrupted the T/A ratio for Ca and K, reducing all models accuracy, with M15's RMSE increasing to 10.78─40.64 mmol c dm−3 (0.33 ≤ RPIQ ≤ 1.23) for av-Ca and to 1.86─6.37 mmol c dm−3 (0.48 ≤ RPIQ ≤ 1.64) for av-K. Although time-specific models improved accuracy compared to M15, they require frequent recalibration. Overall, XRF models can reliably predict plant-available Ca and K over time if soil management maintains a consistent T/A ratio. This study underscores the need to consider soil amendments when applying XRF models for nutrient monitoring and contributes to the theoretical basis for using XRF in agricultural management. • XRF models show long-term stability in predicting plant-available nutrients. • Soil management significantly impacts the temporal stability of XRF models. • Amendments can cause systematic errors in XRF nutrient predictions. • Time-specific models reduce errors but require frequent updates. • Simple XRF models are practical but sensitive to management changes. [ABSTRACT FROM AUTHOR]

Arable soils may play an important role in climate mitigation actions as soil management directly affects carbon (C) sequestration and mineralisation. To evaluate the C sequestration potential in hilly terrain it is essential that not only changes in vertical C fluxes (more C input and/or reduced mineralisation), but also lateral soil organic carbon (SOC) redistribution due to erosion processes are considered. Tillage has been identified as an important contributor to soil translocation processes and a modulator of SOC dynamics. Nevertheless, the focus of most studies dealing with SOC redistribution still lies on water erosion. Therefore, the aim of this study is to assess the impact of tillage erosion on C fluxes in the intensively cultivated loess region (200 ha) in the Czech Republic. The coupled water and tillage erosion and C turnover model SPEROS-C was used to analyse the effect of six decades of erosion/deposition upon C fluxes, whereas a specific focus was set on the importance of tillage erosion processes. The results indicate that tillage erosion (TIL) is an important driver of C dynamics in the study area, especially at slope shoulders where a substantial decline in SOC was modelled. Water erosion (WAT) is the most dominant process in the region. However, the model results reveal an increase in erosion-induced C sequestration potential by 37 % after 60 years of simulation when effect of TIL is considered. Moreover, it is interesting that TIL reduced the total sediment delivery from the monitoring site via a change in topsoil SOC patterns. In other words, tillage lowered water erosion-induced sediment transport. Overall, considering the overlooked impact of tillage erosion led to a substantial shift in the role of soil erosion on SOC dynamics. The climate mitigation measures based on adapted agricultural management to increase SOC sequestration are often in-line with soil conservation measures. Our results indicate that such an adaptation might be less effective as the erosion-induced C sink effect declines. • Our study evaluates the impact of tillage erosion on carbon fluxes on arable land. • Tillage erosion positively influences the overall erosion-induced carbon balance after nearly 60 years of model simulation. • Tillage erosion is a relevant process for the assessment of carbon sequestration. [ABSTRACT FROM AUTHOR]

Soil structure development can be described with tensile and shear processes as well as the further stabilization of interparticle bonds by hydraulic, chemical, biological, and physicochemical processes. The related shrink, swell or stress strain processes, as well as organic bindings and biological glueing processes, however, define the rigidity limits of soil structure and soil functions, which also coincide with defined boundaries that can be applied in modelling approaches. Aggregate formation due to volume separation occurs in soils depending on these interactions and undergo further strengthening or weakening processes with consequences for their rigidity. The goal of this review is to document these processes with corresponding results and to discuss some consequences for global change impacts on, e.g., plant growth and yield or mechanical strength. It is obvious that the hydraulic and mechanical processes have become neglected to some extent in the study of soil structure formation and aggregation, which caused remaining research gaps identified in this review. Consequently, there is an urgent need for a more precise determination of the rigidity limits of soils under various land use and climatic conditions to better predict or model climatic impacts but also the effect of soil management changes or amelioration impacts. • Aggregate formation undergoes intense changes during pedo- and anthropogenesis. • Hydraulic, mechanical, and thermal processes affect internal soil strength. • Structural shrinkage and precompression stress define the rigidity of the pore system. • The rigidity limit is the boundary for the predictability of soil functions • Tensorial hydraulic, stress strain, and thermal functions vary beyond the rigidity limit. [ABSTRACT FROM AUTHOR]

Sustainable cropland management requires preservation of soil organic matter (SOM). In spite of in depth understanding gained from ample field and laboratory studies, we have a poor understanding of landscape scale spatial variation of fresh organic matter (OM) decomposition and its conversion into soil organic carbon (SOC). Particularly, local topographic position may be expected to co-control these processes via soil hydrology. In this study, we sought to identify if such control is significant by setting up a field experiment with two contrasting positions across 10 gently sloping cropland fields covering three different soil texture groups, i.e. loamy sand, (sandy) loam and silt loam. We wanted to link OM decomposition to within-field differences in soil moisture, whilst keeping variation in other soil and management factors minimal. Specifically, mesocosms with 13C enriched ryegrass (the OM source) were incorporated in the fields for ten weeks and afterwards, soil was separated into > 500 µm, 53 – 500 µm and < 53 µm sized fractions. Overall, we found that lower located positions were wetter than higher positions with average differences of 11 %, 20 % and 16 % in water-filled pore space for the loamy sand, (sandy) loam and silt loam soil, respectively. Mineralization of added OM was surprisingly independent of landscape position, even though moisture conditions appeared wetter than optimal at the low but not at the high landscape positions. Remaining ryegrass residues > 500 µm did follow local topography-driven gradients in soil moisture with higher amounts in low landscape positions. In other words, drier conditions at high landscape positions improved coarse OM decomposition, with consequently more ryegrass-carbon (C) ending up in finer soil fractions (< 500 µm). Additionally, soil texture affected decomposition of the smallest fraction (< 53 µm) with a stabilizing effect for finer-textured (silt loam) soils. We conclude that, despite significant contrasts in moisture conditions between landscape positions, within-field spatial variability of OM mineralization was overall limited during the observed wet summer period. Nevertheless, landscape position affected the quality of remnant unmineralized C, with relatively more conversion of freshly added OM into OM associated with silt and clay at the drier higher positions, potentially improving the long-term stability of SOM. Likewise observations under different weather conditions are needed to evaluate the necessity of precise modelling of local soil hydrology for predicting SOC stock evolution on the landscape scale. • Topography in undulating landscapes led to soil moisture contrasts during a wet summer. • Mineralization of added OM was not affected by landscape induced moisture differences. • The moisture contrast did affect the formation of OC in different size fractions. • Soil texture particularly affected mineralization of silt- and clay-associated OM. [ABSTRACT FROM AUTHOR]

Understanding the effects of liming plus phosphate fertilization on soil physical and chemical properties, as well as carbon stock, is critical for improving soil fertility management under conventional till (CT) and no-till (NT) systems. This study aimed to quantify changes in these soil properties resulting from incorporation (CT) or not (NT) of limestone and phosphorus (P) in a subtropical Ferralsol in southern Brazil. The experiment was conducted in Campo Mourão, Paraná State, Brazil, according to a randomized complete block design with a 6 × 4 factorial arrangement and four replications. The treatments comprised six strategies for limestone and P management and four soil depth layers (0–0.05, 0.05–0.10, 0.10–0.20 and 0.20–0.40 m), as follows: NLNT - no liming under no-till; NLCT - no liming under conventional till; LPNT - liming and P fertilization under no-till; LPCT - liming and P fertilization under conventional till; LNT - liming under no-till; and LCT - liming under conventional till. In 2012, 5.0 Mg ha−1 dolomitic limestone and 53.3 kg ha−1 P were applied. In 2016, dolomitic limestone was reapplied to a soybean–wheat rotation. Liming and liming plus P treatments influenced soil properties up to a depth of 0.10 m, increasing pH and decreasing Al3+, without significant differences between CT and NT. Higher levels of Ca2+ and Mg2+ were observed at 0–0.05 m, except in unlimed treatments. Liming and liming plus P fertilization treatments resulted in mean increments of 1.83 and 1.37 cmol c dm−3 in Ca2+ and Mg2+ levels, respectively, regardless of the tillage system. Base saturation did not differ between treatments in the 0.10 m layer. However, LPCT resulted in higher base saturation in the 0.10–0.20 m (55 %) and 0.20–0.40 m (53 %) layers. P contents were affected up to 0.10 m depth, being 30 % higher in LPNT than in LPCT at 0–0.05 m. In the 0–0.05 m layer, soil bulk density was highest in NLCT and LPCT, and macroporosity was lowest in LPCT. Carbon stock was not affected by tillage practices, liming, or P fertilization. There was a positive correlation between P content and carbon stock at 0.20–0.40 m, suggesting that increased P availability at depth contributes to carbon sequestration. At 0–0.05 m, soil physical properties were negatively influenced by the combined application of liming and P fertilization under CT, indicating possible simultaneous effects on clay dispersion and pore obstruction. • P (Mehlich-1) in the soil surface was higher with liming plus phosphorus fertilization under NT system. • Liming plus phosphorus fertilization under CT system affects bulk density and macroporosity in the soil surface. • There is a relationship between P content and carbon stock at depth. • The carbon stock was not impacted by management. [ABSTRACT FROM AUTHOR]

Soil structure governs the functions of soil in many ecosystems, including those dominated by agriculture, such as water and carbon storage, biomass production, and physical stability. Specifically in tropical and subtropical soils, the long-term impacts of different fertilizers on soil functionality and stability in no-till crops are poorly understood. Under subtropical climate conditions, we evaluated how 17 years of continuous fertilizer application (organic vs. inorganic) on no-till crops affected structure of a sandy loam texture, in terms of the pore size distribution and pore functionality for water storage and aeration, and the intra-aggregate pore geometry. The investigated long-term experiment was implemented in a randomized block design with four repetitions in Santa Maria, Brazil. Treatments were pig slurry (PS), cattle slurry (CS), pig deep litter (pig manure with rice husk; PDL), mineral fertilizer (MF), and an unfertilized control (CL) applied in a no-till system. Soil sampling was done in two depths (0–5 and 5–15 cm) to analyze (i) soil pore size distribution, soil water retention, air permeability and pore continuity indices in core samples (± 98 cm³); and (ii) the intra-aggregate pore system using X-ray computed tomography in macroaggregate samples (± 5 cm3). The treatments had different impacts on soil pore functionality and intra-aggregate pore geometry. Only PDL application increased field capacity by around 34 % and the plant available water by about 36 % (compared to all other treatments). Soil air-filled porosity was not affected by fertilizer management in any of the layers. However, in the 0–5 cm layer, fertilizer management had a significant effect on soil air permeability which increased at −6, −10, and −33 kPa matric potential from 6.6, 14.4, and 16.1 µm2 in CL treatment to 29.5, 34.2, and 43.6 µm2 in PDL, respectively. The PS and PDL treatments increased the intra-aggregate porosity and provided a continuous, connected pore network. These fertilizers provided increased biomass productivity (PS and PDL) and soil organic matter content (higher in PDL only). Therefore, continuous application of fertilizer with higher carbon input, such as PDL, improved soil structural conditions and crop yield of sandy soil under subtropical climate. • 17 years of management of organic and inorganic fertilizers affected soil structure. • Only pig deep litter manure increased soil pore functionality for water storage and airflow. • Pig slurry and pig deep litter applications improved the intra-aggregate pore network. • Fertilizer effect on soil structure and functionality was more evident in the surface layer. [ABSTRACT FROM AUTHOR]

The increased focus on soil quality (SQ) aims to conserve land resources and arrest land degradation. However, there are several unknowns regarding which indicators can most effectively indicate specific SQ outcomes and ecosystem functioning. For the first time, this study aims to integrate the soil morphological properties and earthworm population with physical and chemical properties and propose a comprehensive soil quality index (SQI w) to evaluate SQ across a land-use – soil type – climate gradient. Soil profile data (n = 47) covering semi-arid, sub-humid, and humid climates, three soil types (Inceptisols, Vertisols, and Alfisols) and three major land-use systems (grassland, plantation, and annual field crops) were used in this study. As a novel approach, we used a combination of expert opinion and principal component analysis to select 12 soil quality indicators (five morphological, two physical, three chemical, and two biological properties) and developed four thematic SQ indices, viz., morphological quality index (SQI m), physical quality index (SQI p), chemical quality index (SQI c), and biological quality index (SQI b) from the respective SQ indicators using the weighted additive index method. The thematic SQ indices were integrated to create SQI w for surface and subsurface soils. The SQI m showed a strong relationship with SQI p and SQI c and a moderate relationship with SQI b , indicating that the thematic SQ indices can be employed to evaluate soil quality in resource-limited regions or countries. The SQI w differentiated the effects of climate, soil type, and land use management on soil quality and showed a strong correlation with crop yield, enabling the comparison of production systems. The integration of the earthworm population to SQI w is a crucial advancement in SQ assessment, and the SQI m adds a new dimension. The proposed SQI w could be a potential precursor for emerging consensus towards a generalised and comprehensive SQI, which can be effectively used for SQ monitoring across varied land use, soil types, and climate regions. • A novel SQI integrating earthworms and soil morphology with soil properties. • An SQI covering three soil types, three climates, and five land use types. • A comprehensive MDS with twelve soil properties from four themes. • Four thematic soil quality indices were proposed viz., SQI m , SQI p , SQI c , and SQI b. • Surface and subsurface SQIs had strong relationship with crop yield. [ABSTRACT FROM AUTHOR]

Soil erosion is the first threat to soil functions. Reducing the soil aggregate breakdown strength is a key step to improve the soil's ability to resist rainfall splash erosion. Soil internal forces have been found to be the initial and important forces driving aggregate turnover. The application of exogenous organic materials can effectively improve soil aggregate stability and the resistance to rainfall erosion of agricultural soils. However, from the perspective of soil internal forces, information about the reduction effects of the exogenous organic materials application on soil aggregate breakdown is scarce, especially in comparing the effects of different materials. In this study, weathered coal and biochar were individually applied to loamy clay soil at rates of 0 %, 1 %, 2 %, and 3 % (w/w). Soil internal forces, aggregate breakdown strength, and splash erosion rate of different amended soils were then examined after four years. The results showed that compared with unamended soils (0 %), both weathered coal and biochar applications clearly increased the van der Waals attractive pressure and thus decreased the positive net pressure between soil particles. Additionally, these materials reduced soil aggregate breakdown strength and splash erosion rate. The application effects of the two materials were increased with their application rates. Under a lower electrolyte concentration in soil solution (0.0001 mol L−1), the aggregate breakdown strength in the soils amended with weathered coal was lower than that with biochar by 9.6 %, 23.2 %, and 17.7 % (when the diameter of broken aggregate was < 10 μm) and by 10.3 %, 20.8 %, and 17.5 % (when the diameter of broken aggregate was < 20 μm) at the 1 %, 2 %, and 3 % application rates, respectively (P < 0.05). Additionally, soils amended with weathered coal exhibited lower splash erosion rates compared to those amended with biochar, particularly at the higher application rate of 3 %. From the viewpoint of soil internal forces, weathered coal appears to be a suitable exogenous organic material for improving soil aggregate stability and anti-erosion ability during rainfall events. Our findings provide valuable insights into utilizing exogenous materials to improve soil resistance to rainfall splash erosion, assisting agricultural soil management in areas frequently affected by rainfall erosion. • Soil aggregate breakdown strength is highly correlated with soil internal forces. • Both weathered coal and biochar application decreased soil positive net pressure. • Differences in attractive pressure between them increased with application rates. • Weathered coal had greater effects on reducing aggregate breakdown than biochar. • Weathered coal was superior to biochar in improving soil anti-erosion ability. [ABSTRACT FROM AUTHOR]

Improving phosphorus (P) use efficiency is key to improving the productivity and sustainability of cropping systems and slowing the exploitation rate of mineral P resources required for fertilizer production. At present, large amounts of added P in fertilizers and manure each year are retained in the soil and are not used by the crop. This 'legacy P' progressively accumulates in soil and represents an untapped P resource in tropical soils while in temperate soils it contributes to eutrophication. In the context of legacy P, the aim of this study was to quantify changes in soil P pools of contrasting bioavailability (determined using conventional chemical extraction procedures) during 12 successive brachiaria (Urochloa ruziziensis) cropping cycles in which no additional P was added. The study was undertaken in the greenhouse with 10 tropical (Brazil) and 6 temperate (UK) agricultural topsoils. Above-ground dry matter yield (DM) and P offtake was measured at each harvest alongside operationally-defined measures of the labile, moderately-labile and non-labile P pools at the start and end of the experiment. Over twelve repeated cultivation cycles, brachiaria demonstrated an ability to efficiently mine legacy P from all measurable soil pools across both sets of soils. This included the depletion of up to 87 % of non-labile soil P in some soils from the UK and up to 66 % from soils in Brazil after one year. While the amounts of initial labile P showed the closest positive relationship with plant P export, contrary to expectation the non-labile P pool also clearly contributed to plant nutrition across all the soils. As a cover crop, brachiaria clearly possesses traits which enable both the solubilization and efficient capture of soil P that can be harnessed to actively recycle historically non recalcitrant soil P fractions. Incorporating brachiaria into crop rotations or intercropping systems therefore shows promise as a strategy to enhance the longer-term sustainability of soil P management. • Brachiaria extracted P from labile and recalcitrant non-labile P pools in soil. • Soil labile and non-labile P content regulates plant uptake of legacy P rather than P adsorption strength. • Organic P was shown to directly contribute to plant P supply, contrary to recalcitrance paradigms. • Brachiaria cover crops can enhance P use efficiency by solubilizing soil legacy P. [ABSTRACT FROM AUTHOR]

Soil health or soil degradation criteria are until now not well documented for a greater number of soil profiles under conventional and conservation tillage management in the literature. In order to evaluate the compaction status of more than 700 arable sites analyzed within the last 40 years, the Compaction Verification Tool (CVT) was applied according to Zink et al. (2011). Besides the ratio of air capacity (AC, at a matric potential of −6 kPa) and saturated hydraulic conductivity (Ks), the ratio of AC and air conductivity (Ka, at a matric potential of −6 kPa) was considered for evaluating the compaction status with respect to potentially harmful soil alterations. The compaction status was classified into the CVT classes I–IV, where a harmful subsoil compaction was assumed, if both values of AC and Ks or AC and Ka simultaneously exceeded (are smaller than) their defined critical value indicating limited conditions for plant growth (CVT class IV). We analyzed the compaction status of soil profiles with respect to clay content, soil type, structural stage (aggregate forms) and time span of sampling (1980–1999, 2000–2020) under conventional and conservation tillage for top- and subsoil horizons. While also some of the annually plowed topsoils under conventional tillage showed critical values of AC, Ks and Ka, the occurrence of harmful soil compaction is most dominant in the subsoil horizons (> 30 cm depth) because of a higher proportion of class IV which increased with the clay content (from < 12 % to > 12 % clay), irrespective of the applied ratio used for verification (AC/Ks or AC/Ka). Especially the highly productive Luvisols showed a high percentage of harmful compaction in the subsoil (30–41 % in CVT class IV). Soil profiles under conservation tillage management are less affected by harmful compaction. The more aggregated subsoils showed smaller proportions of class IV, which was further influenced by the clay content. • The soil threat by harmful soil compaction (CVT IV) can be explained on the ratio of AC:Ks and AC:Ka. • Luvisols show severe subsoil compaction, documented by a higher number of Class IV subsoil sites. • Soils with clay contents > 12 % are often more intensely deformed than sandier sites. • The ratios between AC and Ks and AC and Ka show similar results. • Soils under conservation tillage are less degraded than under conventional tillage. [ABSTRACT FROM AUTHOR]

Conventional soil management — based on intensive tillage and low input of organic material – negatively impacts soil quality via carbon (C) losses as carbon dioxide emissions (CO 2), exacerbating the effect of climate change on agriculture. Carbon farming practices (CFPs), such as minimum tillage (MT) and strip tillage (ST), offer promising solutions to maintain soil fertility, sustain crop yields, and mitigate environmental impacts. However, applying CFPs in processing tomato (Solanum lycopersicum L.) cropping presents unique challenges due to specific crop and tillage characteristics. Our two-year field study investigated the effects of conservation tillage practices (i.e., MT and ST), both combined with cover crops and digestate application, on soil quality parameters and processing tomato yield. The field studies were conducted in fields with varying soil textures (i.e., clay and silty clay loam), and aimed to evaluate responses in terms of soil C sequestration, nutrient concentrations, soil structure, and abundance of earthworms. We hypothesized that both MT and ST would enhance soil quality parameters also in tomato cropping systems, with ST potentially outperforming MT in C sequestration. Results revealed that CFPs significantly increased soil organic matter, total nitrogen, and available phosphorous compared with conventional tillage. Both MT and ST increased soil C sequestration (up to 1.06 Mg C ha−1 y−1 and 1.21 Mg C ha−1 y−1, respectively) compared with conventional tillage (CT), which lost around 0.88 Mg C ha−1 y−1 under silty-clay loam soil, and had negligible C sequestration (+0.02 Mg C ha−1 y−1) under clay soil. We found no significant difference between MT and ST when using the equivalent soil mass method for calculating C sequestration. Noteworthy, CFPs enhanced fertility parameters without a negative impact on yields, underscoring their potential for enhancing soil C sequestration, improving nutrient availability, and supporting processing tomato yield under adaptation scenarios to climate change. • Carbon farming practices enhance chemical, physical, and biological soil quality. • Combining digestate and cover crops with minimum tillage or strip tillage sequestered 0.83–1.63 Mg C ha−1 y−1. • ST outperforms MT for C sequestration potential with FD method, while not with ESM method. • Processing tomato yield was never negatively affected by carbon farming practices. [ABSTRACT FROM AUTHOR]

Soil organic matter (SOM) is a key factor in sustaining soil fertility, sequestering greenhouse gases and reducing soil erosion, in this regard, an accurate estimation and monitoring of the SOM content is crucial for sustainable land management and climate change mitigation strategies. In recent years, there has been a growing consciousness of the need to better understand the dynamics of SOM across different farm management in time and space. In this context, the main objective of the study is to improve understanding regarding the relationship between SOM and the main farming systems adopted in Italy by taking spatial correlation into account. For this purpose, a large dataset consisting of topsoil SOM values (0–20 cm) and environmental and farming information was collected in 597 locations (145 fields and 62 farms) representative of the whole agricultural area of Po Valley in Italy. This sizable dataset was analyzed by a novel geospatial analysis using a de-clustering approach in combination with polygon kriging for detecting and understanding the SOM variability over the different fields characterized by irregular shapes and different farming systems. The results provided clear evidences of the spatial correlation between SOM, farming systems and soil types. Higher SOM contents were detected in Cambisols (3.11 %) and in field managed according conservation agriculture practices (3.22 %) as compared to other farming systems. Moreover the inclusion of fodder crops in the rotation and the use of no-tillage are two of the most effective practices for increasing and preserving SOM according to our findings. Spatial information, such those provided in this study, could facilitate the delineation of tailored solutions for each European Member State for targeting future actions related to carbon farming, and offering crucial insights to support advancements in agriculture for enhancing soil fertility and health and for fostering sustainable agricultural practices. [Display omitted] • SOM estimation and monitoring is crucial for sustainable land management • Spatial information facilitates tailored solutions for enhancing soil health • A geospatial approach allowed to compare SOM content for the main farming systems • SOM content, farming systems and soil types are significant spatially correlated • Significant higher SOM content in field managed according conservation agriculture [ABSTRACT FROM AUTHOR]

Land management systems that comprise the principles of conservation agriculture (CA) can lead to soil organic carbon (SOC) gains over time. Nonetheless, how fertilization regimes interfere with their performance in highly weathered soils is still uncertain. This study presents results on SOC storage, crop yield, and soil resilience from a long-term experiment in southern Brazil (Ponta Grossa – Paraná State) 26 years after its establishment in 1989 combining a gradient of soil disturbance through diverse soil management strategies with contrasting fertilization regimes. We hypothesized that preserving soil structure rebuilt over time through no-till system plays a significant role in SOC persistence and the fertilization regime can impact land management performance on soil resilience and crop yield. The experimental design was laid out as a split plot through completely randomized blocks. The main plots comprised the treatments related to soil management systems: 1) conventional plow-based tillage – CT; 2) minimum tillage (Chiselling replacing plowing) – MT; 3) no-till with one chisel plowing every three years – NTch; and 4) continuous no-till system – NTS. The sub-plots comprised full crop fertilization (FCF) for all crops and low crop fertilization (LCF) by suppressing K and P fertilization and maintaining N in broadcast application. SOC stocks significantly improved as the soil disturbance diminished, resulting in higher soil resilience indexes for NTS and NTch. Differences in SOC stocks between the contrasting treatments NTS and CT were higher under low fertilization, resulting in C and N sequestration rates of 1.14 and 0.14 Mg ha−1 year−1 under LCF compared to 0.77 and 0.08 Mg ha−1 yr−1 in FCF at the 0–100 cm layer. Such higher differences were induced by overall higher SOC stocks of CT when under FCF and higher SOC stocks in subsoil depths promoted by NTS when under LCF. High fertilization treatments produced cumulative yields 1.5 times higher for soybeans and 2.5 times higher for corn throughout the 26 years of the experiment. Labile C fractions extracted by hot water (HWEOC) and K-permanganate (POXC) were systematically increased as the disturbance diminished. Gains in labile fractions were promoted in deeper layers in lower disturbance treatments (NTch and NTS). We conclude that combining conservation agriculture principles ultimately defined the potential for SOC sequestration. The high soil resilience under the NTS in this research indicates a considerable potential to reverse the soil degradation and decline of the SOC and labile fractions by conversion to intensive NTS (high and diversified annual C input) associated with absence of soil disturbance. [Display omitted] • The no-till system (NTS) storaged more C under full or low crop fertilization. • The NTS had higher Soil Resilience Index than the other management systems. • The soil labile C was higher in NTS and was the pathways to store more C. • The NTS under low crop fertilization exhibited the greater C sequestration rate. • Soil management that involve greater soil disturbance result in higher carbon loss. [ABSTRACT FROM AUTHOR]

Soil erosion exacerbates the loss of soil nutrients and directly affects the soil stoichiometric characteristics. However, the impacts of different erosion conditions and farmland management measures on soil nutrients and their stoichiometry remain unclear. Herein, field observations were conducted in purple-soil sloping farmland in the Three Gorges Reservoir Area, China, using the artificial shovel soil test method. The soil nutrient contents and stoichiometric characteristics of the topsoil under three management measures (no fertilization, CK; chemical fertilizer, F; biochar+chemical fertilizer, BF) and five erosion conditions (erosion thicknesses of 0, 5, 10, 15, and 20 cm) were analyzed. The SOC, TN, TP, TK, AN, AP, and AK contents of the three management measures followed overall decreasing trends with increasing erosion thickness. Under the same erosion condition, the content of nutrient elements in the three treatments followed the trends of BF > F > CK, and the soil nutrient content of the BF treatment was significantly higher than that of the CK treatment (P <0.05). With the increasing erosion thickness, soil C/N, C/P, and N/P ratios of the three treatments showed decreasing trends. The average soil C/N, C/P and N/P ratios for the three treatments were 10.55, 16.92, and 2.09, respectively, i.e., lower than the global and national averages. A lower C/N ratio indicats a faster SOM mineralization rate in the region, with the SOM cumulative rate lower than the decomposition rate. Lower C/P and N/P ratios indicated that crop growth was limited by N, resulting in a state of N deficiency and P enrichment in the soil nutrient in this region, thereby limiting soil productivity. Based on multi-attribute decision making, soil nutrient recovery index, and the characteristics of the response surface, the application of biochar+chemical fertilizer is conducive to alleviating the supply-demand contradiction between crops and soil nutrients, representing an effective way of improving soil fertility. However, further research is required to determine when the application of biochar leads to SOM accumulation that exceeds decomposition. These results provide a scientific basis for the restoration and reconstruction of soil ecosystems in sloping farmlands. • The C–N–P stoichiometric ratios decrease with the increase of erosion thickness. • Crop growth was N-limited, and the soil were in a P-rich and N-deficient state. • The soil nutrient recovery index of biochar+fertilizer treatment was the highest. • Biochar+fertilizer alleviated the supply-demand imbalance of nutrient in crop-soil. • The interaction between erosion and soil management has a synergistic effect on soil. [ABSTRACT FROM AUTHOR]

Proper management practices can turn soils into sinks for atmospheric carbon and mitigate global warming. The objective of this study was to determine how crop residue management affects soil organic carbon (SOC) content in croplands. Data were collected from 323 field experiments evaluating the effect of residue management on SOC. From these, 609 paired data of SOC stocks with residue retained or removed (harvested or burned) were extracted. Meta-analytic methods were used to analyze the data using the response ratio (RR) as an effect size. Carbon input data to the soil from roots and aboveground residue were also extracted from 46 experiments that allowed residue carbon retention efficiency to be calculated. The residue harvest produced a mean decrease in the SOC stock of 11% in the topsoil (≤ 30 cm). This drop was only 5% when the residue was burned. Topsoil and subsoil SOC stock were equally impacted by residue management. In warm areas the relaive drop in SOC due to residue harvest was greater than in cold regions (13% vs. 8%). Likewise, the relative impact of residue harvest is greater in poor SOC soils. In contrast, water availability, soil texture, nitrogen fertilization, residue location, experiment duration and residue type did not significantly affect the RR. The annualized SOC change was greater during the first 10 years of the experiments and then decreased. Residue harvest or retaining had only a minimal impact on root carbon input to the soil, but led to a 6-fold difference in aboveground carbon input. The carbon retention efficiency of aboveground residue decreases over time, dropping from an average of ca. 25% in experiments of less than 10 years to ca. 11% in long (>20 yr) experiments. The results showed that the practice of residue retention is important in all soils to maintain the SOC level, but especially in soils from warm regions and in poor SOC soils. The impact of residue harvest is not only confined to the SOC pool in the surface layer but also impacts on the deep soil layers. • A global meta-analysis showed that residue harvest reduces SOC stock by 11%. • Residue burning had less impact on SOC than residue harvesting. • SOC depletion was similar in topsoil and subsoil due to residue harvesting. • Change in SOC stock occurred mainly during the first 10 years of residue harvesting. • In long-term experiments, carbon retention efficiency of residue carbon rounded 11%. [ABSTRACT FROM AUTHOR]

Vineyards in hilly areas are often prone to erosion because of poor soil development, low soil organic matter (SOM) contents, and severe slopes. Permanent grassing, besides providing protection against erosion, can foster the soil resistance to degradation by increasing SOM that, in turn, favours the formation and limits the turnover of stable aggregates by promoting interactions between SOM and soil minerals. Although a soil's capacity to physically protect SOM is known to depend on management practices, soil properties may interact causing the soil response to vary even at relatively low spatial scales, thereby warranting site-specific sustainable soil management. The objective of this study was to evaluate how differences in soil properties within the same vineyard may modulate the effects of management practices on aggregate formation, stability as well as SOM dynamics. We exploited the spatial differences in soil types and properties in an experimental vineyard by sampling topsoil samples (0–5 cm) with contrasting texture and pH to include a non-calcareous clay loam from an Alfisol (pH 6.8, 18.6 g kg−1 organic C, 28% clay) and a calcareous loam from an Entisol (pH 8.0, 14.8 g kg−1 organic C, 14% clay), both managed for 3 years under permanent grass vs. autumn tillage. Four aggregate size fractions were separated by dry sieving, and characterized for their organic C content and distribution between functional pools by density fractionation, and their resistance to breakdown and organic C loss during wet sieving. Soil type affected aggregate formation and stability with a greater abundance of larger aggregates richer in SOM in the clay loam with respect to the calcareous loam. Tillage enhanced aggregate breakdown and SOM loss, but the effects were highly dependent on the intrinsic soil properties that drive the different mechanisms of aggregate formation and stabilization. The largest macroaggregates were most susceptible to disruption and organic C release by tillage, but a soil-dependent effect was observed as those in the calcareous Entisol were more vulnerable than those in the Alfisol topsoil, particularly due to rapid losses resulting from slaking, swelling and dispersion. Although the aggregates in fine-textured topsoil may be relatively less vulnerable to tillage, the higher proportion of organic C in the larger macroaggregates may make them nonetheless prone to significant organic C loss (in the form of POM (particulate OM) or SOM-rich fine aggregates) unless appropriate management is adopted. Therefore, special attention should be given to the spatial variability in soil properties when planning vineyard management to reduce soil degradation. • Effect of vineyard tillage vs. grassing was investigated. • Inter-vineyard soil variability was included in the study. • Clay-loam soil: higher MWD, more stable aggregates but high potential OC loss. • Calcareaous loam soil: greater structure vulnerability to tillage. • Soil-specific management is needed to prevent soil degradation in vineyards. [ABSTRACT FROM AUTHOR]

Soil salinity is a major environment stress impairing crop production and accelerating soil degradation. Use of soil amendments are practical solutions for altering soil quality to enhance crop productivity in these soils. Hence, we systematically evaluated the impact of soil amendments practices on crop productivity, nutrient use efficiency, soil properties, soil quality index, economics and energetics on soybean-mustard cropping system in sodic Vertisol. In this study, eight treatments comprising of various combinations of soil amendments such as gypsum (@2.5 t ha−1), farmyard manure (FYM@10 t ha−1), crop residue (CR@1.5 t ha−1 of soybean residue during rabi and 3 t ha−1 of mustard residue during kharif season) with recommended fertilizer doses (RNPK) was evaluated in randomized block design with three replications for four consecutive years in soybean-mustard cropping sequences (2016–2019). Results demonstrated that application of gypsum with CR and FYM recorded a significant drop in exchangeable sodium percentage (ESP) (45–48 %), and bulk density (BD) (3–6 %) than that of control. Organic amendment in conjunction with gypsum and chemical fertilizer significantly improved soil chemical, physical and biological properties than that under control and inorganic fertilizer alone treatments. Based on principal component analysis and correlation matrix, minimum data set identified ESP, pH, BD, organic carbon, available nutrients, biomass carbon, calcium content, dehydrogenase as the most important properties controlling soil quality. Integration of RNPK+Gypsum+CR and RNPK+Gypsum+FYM are found superior leading to higher crop yield in soybean (1.23 and 1.21 Mg ha−1 respectively), mustard (1.43 and 1.39 Mg ha−1 respectively), better nutrient recovery efficiency (77 and 53 % respectively), improved soil quality index (0.90 and 0.93 respectively), and higher economic return (benefit: cost ratio-2.88 and 2.1 respectively).Therefore, this study findings highlighted the conjunctive use of gypsum with organic amendments is effective in reclaiming salt stress, improving soil health and crop productivity under oilseed cropping sequence in degraded soils of semi-arid tropics. • Soil management practices for oilseed cropping system was assessed comprehensively. • Soil amendments improved soil physical, chemical and biological properties. • Improved crop nutrient use efficiency with soil amendments in sodic soils. • Soil amendments impact on soil quality index and crop yield. [ABSTRACT FROM AUTHOR]

This research focuses on two science-based soil quality assessments, i.e., visual soil assessment (VSA) and analytical (lab-based) soil quality (SQ) assessment. The VSA, especially when conducted by farmers, offers a cost-effective approach to studying soil in extended study areas. However, little is known about the applicability of VSA in areas subjected to different degradation processes. Our study takes place in the lowland, midland, and highland agro-ecological zones (AEZs) of the Shafe and Sile-Elgo catchments, in the Southern Main Ethiopian Rift Valley. It aims to contribute to the state-of-art knowledge on VSA by evaluating its reproducibility when conducted by farmers and extensionists and its correlation to analytical SQ indicator scores, and to generate insight into SQ of the cropland in the various AEZs of two selected catchments. To that aim, 36 cropland fields were selected, half of these fields receiving soil and water conservation (SWC) practices, while no SWC was applied to the others. In each field, the VSA was conducted by farmers and experts, followed by laboratory analyses and calculation of an SQ index. Our finding reveals that overall VSA scores assigned by both groups were very strongly correlated (r=0.909–0.975, p<0.001) and reproducible at any level of stratification in the highly diverse, tropical study area covered in this research. However, the VSA indicator soil texture turned out to be non-reproducible. Both VSA and analytical SQ indicator scores are significantly (p<0.05) higher in fields receiving SWC practices and integrating both methods provided a clear contrast between fields that have good and poor SQ conditions in different AEZs of the catchments. The VSA method is less capable of capturing problems related to toxicities or low nutrient and water availability as a consequence of acidity, salinity and sodicity. Therefore, when the VSA method is applied to monitor SQ status of fields subjected to diverse degradation processes, it would be better to include specific indicators of pH and EC. • Visual soil assessment proves applicable in environmentally diverse catchments. • Visual and analytical soil quality assessments are distinctive for management. • Visual techniques offer a more comprehensive assessment of soil compaction. • Integrated assessments can evaluate soil quality for a wider range of threats. [ABSTRACT FROM AUTHOR]

Semi-arid regions of Central Asia suffer from wind erosion due to expanding steppe conversion and unsustainable farming practices. Empirical data from field observations are needed to support the implementation of adapted management. In this study, a mobile wind tunnel was used for the first time in Kazakhstan to assess the soil's erodibility under real conditions. Field experiments were conducted on loamy sands with different initial conditions that are typical for the most erosive time of the year: a bare surface with a cloddy structure after recent steppe conversion, a weak crust on a plot with barley (Hordeum vulgare L.), and a plot with loose material in the rows of maize plants (Zea mays L.). Subsequently, different levels of mechanical stress (low, moderate, high) were considered to analyze the effect of disruptive forces soils experience during field cultivation (light cultivator, disc harrow, tractor tires) on possible soil losses. The results of wind tunnel experiments showed already great differences under initial conditions. The cloddy structure of the recent steppe conservation had the lowest susceptibility against wind erosion due to a good aggregation and a large roughness, resulting in soil loss of 12 g m−2. The plot grown with barley was less affected by wind erosion due to the weak crust, smaller distances between plants, and leaves close to the ground (soil loss of 34 g m−2). Maize was also the most problematic crop in the study area because wind can blow below the plant canopy without considerable resistance during the early growth stages. Additionally, existing deposits in the maize rows from previous erosion events led to the highest soil loss of 1609 g m−2. Mechanical stress by seedbed preparation generally increased the erodible fraction, resulting in higher soil losses (light cultivator: 198 ± 129 g m−2, disc harrow: 388 ± 258 g m−2). The most severe disruption of soil structure occurred on tractor tire tracks, causing a loss of 2767 ± 1810 g m−2. Consequently, the pulverizing effect of tractor tires on dry soil must be considered a serious emission source. Comparing the soil organic carbon content of topsoil and eroded material showed that organic carbon was enriched only in the aeolian sediments of the recently converted plot (+69%). We conclude that soils after steppe conversion need to be treated with particular care from the very beginning so that severe events from the past are not repeated. • First wind erosion study with a mobile wind tunnel in Kazakhstan. • Vegetation, aggregation, and tillage as erosion-controlling factors were tested. • Mechanical stress from seedbed preparation determines soil susceptibility to wind erosion. • Tractor tire tracks must be considered a serious emission source. • Steppe conversion requires best-adapted measures of erosion prevention early on. [ABSTRACT FROM AUTHOR]

Conservative agricultural management strategies pursue long-term ecological benefits through practices such as no-tillage, cover crop, and inherent soil properties management. Farmers, however, are often hesitant to adopt such practices due to lack of experience, initial expense, and concern for low crop productivity. Overcoming this barrier requires novel approaches, such as effectively managing the soil microbiome to attain high productivity at a low cost, especially in a semi-arid region. To study the potential of conservation agriculture, we investigated components of soil bacterial community and rhizobial diversity in long-term experimental cotton fields divided into conventional tillage monoculture systems with winter fallow (CT) and no-tillage with mixed cover crop (M-NT) system on the Texas High Plain (THP). We conducted next-generation amplicon sequencing targeting rpoB gene with collected soil samples from different soil managements and seasons. Our research revealed that although CT had significantly greater bacterial diversity and species richness than the M-NT management, rhizobial diversity and species richness were higher in M-NT than in CT management. Both bacterial and rhizobial diversity and richness were greater in summer than in fall. The abundance of the order Rhizobiales was consistently high in M-NT than in CT fields in both seasons. Soil management altered the dominant rhizobial genus associated with cotton production systems; Rhizobium and Pararhizobium dominated M-NT management, while Bradyrhizobium and Sinorhizobium were dominant under CT management. These outcomes suggest that incorporating legumes into a cover crop in this semi-arid cotton-growing region can initiate beneficial changes to the dynamics of the indigenous rhizobial assemblage. The high prediction accuracy of our machine learning model using bacterial community data classifying the managements as CT or M-NT validates the possibilities of a strong underlying relationship between soil management and the bacterial diversity in the soil. • Overall soil bacterial diversity is higher under CT management. • Rhizobial diversity is higher in M-NT management. • Management practices alter bacterial and rhizobial assemblage composition. • The abundance of order Rhizobiales is higher under M-NT management. • Machine learning model recognizes management types with high prediction accuracy. [ABSTRACT FROM AUTHOR]

The objective of the study was to elucidate the relationship between soil management and carbon (C) stocks, and to identify the factors that intervene in the processes that favor C sequestration. The study was carried out on a farm in the Argentinean semiarid pampas with four land management practices (2019–2021): natural grassland (NG), crop-pasture rotation (RO), soybean monoculture (S-S) and with cover crop (S-CC). Aerial and root biomass were quantified at cover crop termination and soybean flowering. In addition, residues on soil surface were determined two times a year. In all cases, C and N contents were quantified. On composite soil samples, soil organic C (SOC), particulate C (POC), microbial biomass C and N (MBC, MBN), and soluble C and N were determined at 0–0.1 m depth. Results showed that NG had the highest and the most stable aboveground (3807.1 kg residue-C ha-1) and belowground inputs between years (4965.8 kg root-C ha-1). Similar results were observed in RO treatment during the first year (4221.0 kg root-C ha-1) diminishing by 67% after plowing for the annual crop in the second year reaching similar root-C values than S-CC and S-S (721.7 kg ha-1). S-S presented the lowest aboveground (49%) and belowground inputs (77%) compared to NG. Cover crops (S-CC) contributed with 31% and 14% of extra residue-C and root-C, respectively, compared to S-S. MBC showed a non-linear response with increases in root-C, reaching maximum carrying capacity of 110.6 ± 4.3 kg MBC ha-1 with root-C inputs ≥ 2200 kg ha-1. Our results showed significant relationships between root-C and POC and SOC, while no relationships were found for aboveground residues. Increases in soluble N explained 86% of SOC variability. Both RO and S-CC reached the "4 per Mille " goal with an average annual SOC storage rate (ΔC) of 0.24 and 0.16 Mg ha-1 y-1, respectively, while S-S had SOC losses of 0.04 Mg ha-1yr-1. [Display omitted] • NG had higher and stable inputs with 15% more root-C than residue-C. • RO-pasture had similar root-C as NG, diminishing by 67% after plowing. • S-CC contributed with 31% and 14% more residue-C and root-C than S-S. • Root-C and soluble N explained increases in SOC. • Both, RO-pasture and S-CC reached the "4 per Mille " goal. [ABSTRACT FROM AUTHOR]

Soil permeability associated with pore characteristics is a critical factor affecting water and nutrient transport in agricultural fields. However, which soil pore characteristics determine soil permeability remains inconclusive due to high heterogeneity of soil pore structure affected by soil and crop management practices. The objective of this study was to compare the pore characteristics of soils under various field management and assess the performance of different pore radii in estimating soil permeability. In this study, we utilized X-ray computed tomography (XCT) to quantify the pore characteristics of soil cores from three treatments: no-tillage under continuous maize cropping (NT-MM), no-tillage under continuous soybean cropping (NT-SS) and conventional tillage under continuous maize cropping (CT-MM). Subsequently, we calculated the permeability with pore-scale numerical simulations directly based on XCT images. Our results revealed that compared to the NT-MM treatment, the NT-SS and CT-MM treatments significantly increased soil porosity of > 200 µm pore classes (soil depths of 2–8 cm and 2–14 cm), as well as pore compactness, specific surface area, fractal dimension, and global connectivity. Among the three XCT-derived pore radii, the critical pore radius (CR) exhibited excellent performance in estimating permeability for samples from the NT-SS and CT-MM treatments, surpassing the hydraulic radius (HR) and mean pore radius of the limiting layer (MRLL). For samples from the NT-MM treatment, the CR and MRLL had similar estimation capabilities (R2 = 0.429, P = 0.110), but both were not as good as the HR (R2 = 0.539, P = 0.060). Furthermore, when estimating the permeability of all the aforementioned soil samples, the CR demonstrated the best estimation performance (R2 = 0.838, P < 0.001). In conclusion, utilizing CR as a predictor for estimating permeability in naturally structured soils is a good choice, which provides valuable insights into improving the accuracy of estimating soil permeability. • Soil permeability was estimated by numerical simulation based on XCT images. • Relative to NT, the CT presented greater XCT-derived porosity at plow layer but less biopores. • Relative to MM, the SS increased the XCT-derived porosity with larger biopores. • The critical pore radius estimated permeability best among the three pore radii. [ABSTRACT FROM AUTHOR]

Soil structure mediates soil functioning and can be influenced by agricultural management practices (cropping intensity, tillage, and nitrogen source). This study evaluated the effectiveness of multiple soil aggregate indices to quantify soil structural development using long-term data from three locations within the central Great Plains: Alternative Crop Rotation (ACR) and Long-Term Tillage (LTT) near Akron, Colorado, and Knorr-Holden (KH) near Mitchell, Nebraska. Tillage treatments include no-tillage (NT), reduced tillage (RT), conventional tillage (CT), and moldboard plow (MP). Commercial mineral fertilizer (F) was used as a nitrogen source in ACR and LTT sites while manure (M) plus F treatments were used in KH. Soil aggregate size classes were measured in the laboratory, and aggregate stability index (ASI), mean weight diameter (MWD), geometric mean diameter (GMD), and fractal dimension (FD) were calculated to evaluate soil aggregation using linear regression and principal component analysis (PCA). At 0–15 cm, intensive tillage treatments (CT and MP) in ACR and LTT, reduced (P < 0.05) ASI by 46.7%, MWD by 21.0% and GMD by 8.4% and increased FD by 0.77% compared with NT and RT treatments. The addition of manure increased (P < 0.05) ASI by 72.2%, MWD by 65.6%, GMD by 32.8%, and reduced FD by 5.5% compared with tillage treatments in ACR and LTT. The PCA indicated clear effects of M on aggregate structure and stability, indicating that manure addition could compensate for the tillage operations in sustaining soil structural stability. Explanatory variables FD and ASI were orthogonal across the three sites, while FD was negatively correlated with MWD and GWD; thus, FD provides information not captured by ASI and complements MWD and GWD. The evaluated indices, including FD, are effective in measuring soil aggregation and structural stability and should be considered further in management decisions to sustain soil resources and enhance economic returns. The methods developed here can be applied to any site where soils are sampled and analyzed for aggregates. • Soil aggregate indices (MWD and GMD) and stability (ASI) correlated positively with soil organic carbon. • A fractal dimension (FD) of soil aggregate size classes correlated negatively with MWD, GMD and ASI at each site. • Including FD with other indices in principle component analyses (PCA) revealed management effects on soil aggregation. • The PCA across sites revealed orthogonality between variables ASI and FD, with manure effects on soil aggregation. [ABSTRACT FROM AUTHOR]

Microbial activity is a sensitive indicator of soil structure improvement provided by plant species in the physical recovery of compacted soils. This study aimed to assess the impacts of crop species on soil aggregate classes for soil recovery after compaction and identify which microbial attributes best describe the structural quality index for soil physical health in an Oxisol under no-tillage. The experiment comprised three crop species—maize, ruzigrass, and black oats—cultivated under four degrees of compactness produced by chiseling or machine traffic under long-term no-tillage. Soil aggregates were separated by dry sieving into five diameter classes to assess the basal respiration, microbial biomass carbon, metabolic quotient for CO 2 (q CO 2), labile carbon, cellulase activity, and total organic carbon. The values of microbial indicators for the bulk soil were estimated as a weighted mean of each attribute using aggregate size distribution. The lowest values for total organic carbon, labile carbon, and microbial biomass carbon were observed in aggregates > 4 mm. The basal respiration values increased from 8.2 µg C-CO 2 g d−1 in the aggregates > 4 mm, to 22.1 µg C-CO 2 g soil d−1 in the aggregates < 0.5 mm (+170%). Similarly, the cellulase activity increased approximately four times comparing aggregates > 4 mm (38 µg glucose g−1 d−1) to those < 1 mm (181 µg glucose g−1 d−1). The total organic carbon and microbial biomass carbon were found to be little affected by crops. However, the plots cultivated with black oats or ruzigrass exhibited higher cellulase activity, basal respiration, and q CO 2 in comparison with maize, primarily due to the greater content of labile carbon. Increasing the mean weight diameter from 3 mm to 8 mm led to a decrease in the labile carbon (−27.4%), microbial biomass carbon (−25.5%), cellulase activity (−70%), and basal respiration (−21.6%), thereby revealing negative effects of soil compaction on microbial attributes. The degree of compactness did not influence the values of total organic carbon and q CO 2. The response of the microbial indicators depends on the aggregate diameter classes. The results of this study indicate that cultivation of cover crops decreases the negative impacts of soil structure degradation on soil microbial quality. Cellulase activity and labile carbon were considered as new potential indicators of soil compaction for soil physical health studies—highly sensitive and quickly responsive to managements that induce soil structure changes in an Oxisol. • We tested the microbial attributes as a soil structural indicator. • Soil management affect biological indicators of soil physical health. • Soil aggregate quality were evaluated by microbial attributes. • Cellulase activity and labile carbon in aggregates may use as a soil physical health assessment. • Soil compaction is identified by the microbial attributes inside the soil aggregates. [ABSTRACT FROM AUTHOR]

• Zero tillage is a philosophical ideal for soil conservation. • The ideal can be in conflict with the need to manage soil and agronomic constraints. • We measured the detriment caused by a single tillage and the subsequent recovery. • One tillage caused minor loss of wet aggregate stability and no effect on hydraulic conductivity. • Recovery time was generally 1–2 years but for one site-year exceeded 2 years. Occasional, strategically applied tillage within an otherwise no-till system conflicts with the philosophical ideal of zero disturbance of soil, yet is often needed to manage soil constraints, pests and weeds. This study reports the impacts of a single strategic tillage applied to long term no-till soils (10–16 years) with a scarifier or offset discs, compared with ongoing no-till, on soil conditions and crop growth over four seasons at three locations in southern New South Wales, Australia. The tillage occurred just prior to sowing in autumn and under different management conditions at each site. The effect of a single tillage on wet aggregate stability (WAS) ranged from 0 to 14% loss of macro-aggregates, and the recovery time was generally one or two years with the exception of one site-year. The effect of a single tillage on saturated hydraulic conductivity was not statistically significant. Crop establishment was decreased by tillage in some site-years but effects on crop dry matter and grain yield tended to be neutral or minor. In most cases, seasonal effects and crop sequence had a much larger effect on crop productivity than tillage. The results demonstrated that strategic use of tillage within an otherwise no-till system generated minor and short term impacts on soil conditions. Strategic tillage therefore provides a tool for more flexible management of soil, pest and weed constraints to ensure long term productivity and sustainability of dryland mixed farming systems in southern New South Wales, Australia. [ABSTRACT FROM AUTHOR]

• After 30 years of no-till, the amount and type of organic-P was similar to the natural biome. • No-tillage guaranteed higher inorganic and organic P, labile and moderately labile. • 40-yers of CT resulted in the labile and moderately labile P similar to natural forest. • Winter cover crops have despicable or absent effect on P-polls compared with fallow. The no-tillage system combining winter cover crops and crop rotation may increase the efficiency use of soil P and phosphate fertilizer. The objective of this study was to evaluate the effect of three decades of different soil management systems and winter cover crops on the fractions of P in a clayey Oxisol of Paraná State, Brazil. The bi-factorial experiment with three replicates was established in 1986. The main plots consisted of seven winter cover crops. In the subplots, two tillage systems were used: no-tillage and conventional tillage. The soil was sampled in the 0–10 cm soil layer in each plot in the post-harvest of the corn (March 2015), the flowering of the winter cover crops (September 2015) and at soybean flowering (February 2016). Samples from a native forest adjacent to the experimental area were also taken for comparison. The different pools of P were evaluated. Results indicated that after 30 years of no-till with phosphate fertilizers addition, the amount of P organic pools and type of P organic compound were very similar to those observed in the natural biome. The no-tillage guaranteed higher inorganic and organic P, both rapid and moderately available, in comparison to the conventional tillage system. However, in the conventional tillage (40 years − 80 plows + 160 harrows), despite the addition of 3 Mg ha−1 of P 2 O 5 , the available and moderately labile P content in soil surface were very similar to soil under natural forest. In the natural biome, the amount of P stored in soil microbial biomass was stable in the time showing a homeostatic equilibrium. Nevertheless, in cultivated soil and fertilized with inorganic phosphate, there was a synchronism between plant demand and storage in soil microbial biomass. Except for P stored in soil microbial biomass, the other P pools, regardless its nature (organic or inorganic) or degree of bioavailability, had despicable or absent effect of winter cover plants, compared to winter fallow. [ABSTRACT FROM AUTHOR]

• SWAT model was used to evaluate best management practices (BMPs) for sediment and nutrient loss control. • SWAT model could successfully be used for identifying the critical sub-watersheds for soil management purpose. • Cultivation of groundnut and soybean recommended over paddy and maize. • Field cultivator tillage practice and conservation operations significantly affect sediment yield and nutrient loss. The intensive study of an individual watershed is required to develop effective and efficient watershed management plans. Identification of critical erosion-prone areas of the watershed and implementation of best management practices (BMPs) is necessary to control the watershed degradation by reducing the sediment and nutrient losses. The present study evaluates and recommends the BMPs in an agriculture-based Marol watershed (5092 km2) of India, using a hydrologic model, Soil and Water Assessment Tool (SWAT). After successful calibration and validation, the model simulated daily/monthly discharge and sediment were found satisfactory throughout the simulation period. The model was then applied with a calibrated set of parameters for evaluating the effectiveness of various management practices for sediment and nutrient loss control. Keeping in mind the existing agricultural practices, socio-economic aspects and geography of the study area, the management practices were focused on four crops (Maize, Rice, Soybeans and Ground nut), three fertilization levels (high, medium and low), four tillage treatments (Field cultivator, Conservation tillage, Zero tillage and Mould board plough), and two conservation operations (Contour farming and Filter strips). The simulated annual average sediment yield from the watershed was found to be 12.2 t.ha−1yr−1. The water balance analysis revealed that, the evapo-transpiration is predominant over the watershed (approximately 46.3% of the annual average rainfall). Reduction in sediment yield and nutrient loss was observed with alternate cropping treatments of Groundnut and Soybean, as compared to Paddy and Maize cultivation. Overall, based on simulated results, the field cultivator tillage practice and conservation practices viz., contour farming and filter strips, could be adopted to reduce sediment yield and nutrient losses in the critical sub-watersheds of the study area and in other watersheds with similar hydro-climatic conditions. [ABSTRACT FROM AUTHOR]

• Disturbance in the form of chisel plow tillage negatively impacts GHG efflux. • Carbon dioxide flux from soil is doubled after tillage and remains elevated for one week. • Nitrous oxide flux from soil is increased after chisel plow tillage. • Methane assimilation decreased after chisel plow tillage. • No-till practices reduced GHG efflux, resulting in soil carbon and nitrogen conservation. Soils produce greenhouse gases (GHG) from carbon (C) and nitrogen (N) mineralization. The GHGs of interest in cropped soils are carbon dioxide (CO 2), nitrous oxide (N 2 O) and methane (CH 4). Greenhouse gases of cropped soils in response to management disturbance in the Southern Plains of the United States after tillage have not been monitored and reported to date in the literature. It was hypothesized that undisturbed no-tillage treatment would produce less CO 2 , CH 4 , and N 2 O emissions compared to conventional tillage due to a flush of labile N and aeration of soil immediately after tillage. Methane emissions were hypothesized to increase following tillage due to disturbance. This study was conducted at the United States Department of Agriculture, Agricultural Research Service, Grazinglands Research Laboratory at El Reno, OK on 21–28 July 2015 and 25 July–August 1, 2016, post-harvest. Efflux rates of GHGs were monitored using stationary chambers and soil nitrogen, carbon and water were monitored before tillage, 0, 3, 6, 9, 24, 48, 96, 168 and 336 h after tillage in conventional (CT) and no-till (NT) management systems. Soil water content was lower in CT than NT in both years. Tilling the soil resulted in a doubling of CO 2 and N 2 O efflux. Methane assimilation decreased by two fold post tillage compared to before tillage efflux. Soil nitrate and ammonium increased after tillage and remained elevated. This study confirmed that water-filled pore space (WFPS) was an important driver of CO 2. Mechanical disturbance through tillage appeared to be the biggest driver of N 2 O efflux and produced a flush of soil N. However, soil N availability, as a result of tillage, caused a transition of assimilation to efflux for CH 4 that was not affected by WFPS. [ABSTRACT FROM AUTHOR]

• Soil health index (SHI) was developed at a village level under both conceptual and PCA framework. • Clay loam soil exhibited higher SHI than the sandy soils. • Direct seeded rice followed by zero tillage wheat showed higher SHI than conventionally tilled rice-wheat system. • Green manuring practice could be more effective than FYM for enhancing soil health. • The prototype of a soil health card was developed with proper recommendation for efficient management of soil. Soil health card (SHC) based management is needed for efficient management of resources and sustainable crop productivity. Soil health index (SHI) could be used as a yardstick for judging the health of the soil. Soil management and assessment framework (SMAF) is widely used to develop soil health indices to assess the impact of different management practices in cropping systems. The three steps used under SMAF are indicator selection, indicator interpretation, and indicator integration into a unified soil quality index. Soil samples were collected from farm fields with diverse management histories. This included application of farm yard manure (FYM), green manure (GM), no manure (NM). The tillage practices used by the farmers were direct seeded rice followed by zero tillage wheat (DSR-ZT), conventional tillage rice followed by zero tillage wheat (CT-ZT), system of rice intensification followed by zero tillage wheat (SRI-ZT) and CT rice followed by CT wheat (CT-CT). The soils were analysed for pH, electrical conductivity (EC), soil organic carbon (SOC), Active carbon (AC), available nitrogen (Av-N), phosphorus (Av-P), potassium (Av-K), iron (Av-Fe), manganese (Av-Mn), zinc (Av-Zn), copper (Av-Cu), bulk density (BD), maximum water holding capacity (MWHC), aggregate stability (AS), microbial biomass carbon (MBC), dehydrogenase activity (DHA), potentially mineralizable nitrogen (PMN). Minimum data set (MDS) decided in conceptual framework (CF) were further reduced by principal component analysis (PCA). The PCA screened SOC, Av-Zn, Av-Mn, Av-K, AS, MBC and PMN as most sensitive soil health indicators. The SHI developed by CF and PCA were significantly correlated with each other suggesting that PCA approach with limited soil parameters could be adequately applied for development of SHI. There were enough variations in the MDS for developing scoring curves that facilitated successful scoring of the data. Native soil texture significantly influenced the SHI; sandy clay loam soil showed highest SHI (0.67) followed by sandy loam (0.57), loamy fine sand (0.44), and fine sand (0.35) soils. Among the manuring management practices, GM showed the highest SHI (0.56) followed by FYM (0.49) and NM (0.47). Among the tillage practices, DSR-ZT showed highest SHI (0.76) followed by CT-ZT (0.59), SRI-ZT (0.55) and CT-CT (0.49). The soil health card developed has vital information on farmers, field location, soil type, and cropping practices. The soil health card also has information on eleven chemical indicators, four physical indicators and three biological indicators and SHI. The SHC has additional advantage over routine soil testing in terms of presenting information on health status of the soil as impacted by different management practices, amelioration recommendations and crop specific fertilizer and manure recommendations. [ABSTRACT FROM AUTHOR]

• Soil nutrients were evaluated for contribution to grain Zn in different regions. • Soil Fe inhibited Zn accumulation in wheat grain in single wheat region. • High P and low Zn in soil inhibited Zn increase in wheat grain of wheat-maize region. • Soil Amon-N was a dominant factor for grain Zn in rice-wheat region. • Integrated soil nutrient management is needed for grain Zn improvement regionally. It is useful to understand soil nutrients responsible for grain zinc (Zn) variation of winter wheat (Triticum aestivum L.) in different cropping regions, in order to adopt appropriate soil management measures to improve grain Zn nutrition and alleviate human Zn malnutrition. A total of 599 wheat plant and corresponding soil samples were collected from farmers' fields in three typical wheat cropping regions of China in 2015 and 2016, to determine the dominant soil nutrients related to high grain Zn concentration. Obtained results showed that a large variation in grain Zn existed within different regions, with 8%, 9% and 16% of grain samples reaching the recommended level of 40 mg kg−1 in the single wheat, wheat-maize and rice-wheat regions, respectively. In the single wheat region, grain Zn was positively correlated with soil available potassium (K) and Zn, and negatively correlated with available iron (Fe) (P < 0.001), with the available K being 164 and 117 mg kg−1, Zn 0.64 and 0.46 mg kg−1, and Fe 3.3 and 5.2 mg kg−1 for the high and low Zn groups, respectively. In the wheat-maize region, grain Zn was positively correlated with soil available Zn, while negatively correlated with available phosphorus (P) (P < 0.001), with the available Zn being 1.7 and 1.3 mg kg−1, and P 24 and 25 mg kg−1 for the high and low Zn groups, respectively. In the rice-wheat region, grain Zn was positively correlated with soil ammonium nitrogen (Amon-N) and available Zn (P < 0.001), with Amon-N being 7.2 and 4.6 mg kg−1, and available Zn 1.9 and 1.2 mg kg−1 for the high and low Zn groups, respectively. Therefore, it is possible to produce wheat with grain Zn higher than 40 mg kg−1 in farmers' fields, and apart from available Zn, soil available K and Fe in the single wheat region, available P in the wheat-maize region, and Amon-N in the rice-wheat region should also be considered for the purpose of grain Zn improvement. [ABSTRACT FROM AUTHOR]

• The 13C recovery was affected by soil management and the types of exogenous carbon. • More carbon was distributed in the mineral grains of paddy soil than upland soil. • In paddy, protection of organic carbon was proportional to the increase of fractions < 2.65 g.cm−3. Low molecular weight organic carbon (LMWOC) can be physiochemically protected by soil particles via sorption and enfolding. Soil management usually changed the soil particle distribution (e.g. upland vs paddy soil). Higher organic carbon stocks in paddy soil than upland soil could partially be because of the greater immobilization and inaccessibility of LMWOC in paddy soil. To assess the effects of soil management and types of LMWOC on its carbon stabilization in soil density fractions, a simulated study was conducted to investigate the distribution of LMWOC (i.e., glucose, acetic acid, and oxalic acid) in soil density fractions based on 13C-labeling experiments in both soils. The results showed that the total 13C recovery was determined by LMWOC types, following the order of glucose> acetic acid > oxalic acid (p < 0.05). Both soil management and types of LMWOC significantly affect carbon distribution in soil density fractions. The 13C from LMWOC was predominant in the 1.85–2.4 g.cm−3 fraction of upland soil, while the highest concentration of LMWOC 13C was found in mineral grains (2.4–2.65 g.cm−3) in paddy soil, suggesting that more LMWOC was preserved in high density fractions in paddy soil than in upland soil. Our results highlighted that the LMWOC was mainly associated with aggregates in upland soil while subjected to mineral adsorption in paddy soil. [ABSTRACT FROM AUTHOR]

The Visual Evaluation of Soil Structure (VESS) method has been used frequently to evaluate the structural quality of soils from various parts of the planet, under different edaphoclimatic conditions and cultivation practices. In this context, this paper hypothesised that VESS is sensitive enough to detect differences between structural quality (Sq) scores of VESS from soils with different textural classes, submitted to distinct management and cultivation practices, under contrasting climates. To test this hypothesis, a systematic review and meta-analysis of global scope were conducted, with the objective of compiling and analysing all indexed scientific papers that utilised the method. Exclusion criteria were adopted with the intention of eliminating papers that did not meet the selection criteria for the meta-analysis, however, these papers were used in the systematic review. A sensitivity analysis was performed prior to the meta-analysis in order to evaluate the heterogeneity in the data set, thus increasing the scientific validity of the overall analysis. The results obtained through the systematic review showed that the number of studies using VESS has grown in recent years, not only in temperate regions, but also under diverse soil conditions and cropping systems in subtropical and tropical regions. The meta-analysis showed that temperate soils presented lower Sq scores compared to those observed in tropical and subtropical soils, whereas higher Sq scores were observed in clayey/silty soils compared to sandy soils, regardless of climate zone. Our findings also revealed that Sq scores differences induced by soil management and cropping systems were not detected by the meta-analysis. Thus, the VESS is an on-farm, practical and reliable tool for evaluating the structural quality of soils globally. [ABSTRACT FROM AUTHOR]

Highlights • Critical moisture for crop in each phenological stage was added as the lowest limit of LLWR. • Water uptake in soil profile improved with deep tillage, intercropping and additional gypsum. • Soil physico-chemical conditioning was important to maintain plant water status. • Unlike plants aerial growth, average yield of first years are the same among management systems. • Intercropping with Brachiaria reduces soil moisture but not lead water stress to Coffee plants. Abstract Water determines the success of coffee farming, since it influences the phenology of the plant and, consequently, its productivity, product quality and commercial viability. The Least Limiting Water Range (LLWR) associated with the monitoring of soil water content (θ) distinguishes management systems as to their effectiveness in supplying water to plants. The need for developing better management systems –in Brazilian rainfed farming– that promote water uptake by coffee plant radicular systems at lower soil depths where water is more available, inspired this study. This work had as an objective to evaluate the availability of water in soil through LLWR limits in association with leaf water potential, as well as growth and yield of coffee plants, in the Cerrado region of Southeastern Brazil over 4 years. The management systems evaluated were: CV-0 (conventional management with coffee interrow maintained with bare soil); G-28 (conservation management, with maintenance of Brachiaria in interrow, ridging and additional application of 28 Mg ha−1 gypsum applied in the rows) and G-7 (same as G-28, except for an additional application of 7 Mg ha−1 of gypsum). θ was monitored every 15 days. Critical moisture for coffee crop in each phenological stage was added as the lowest limit of LLWR. In all evaluated management systems, θ was below the critical moisture as measured at the soil depths of 0.20 m and 0.60 m. At 1.00 m depth in the CV-0 management system, the greatest value of θ was found, which caused the assumption of smaller water uptake. Regardless of the management adopted, the leaf water potential reached -1.16 MPa in August 2010, but that did not cause water stress high enough to reduce productivity. At 0.60 m depth, the lowest value for θ between rows was observed for the G-28 management system. Plants showed a more accentuated initial growth in the CV-0 management system. Each management system showed distinct behavior regarding productivity of the evaluated crops: in 2011, CV-0 had the highest productivity, but, in 2012, productivity was greater for G-7 and G-28. [ABSTRACT FROM AUTHOR]

Highlights • The 4 per 1000 target is equivalent to 3.4 GtC per year over 0–40 cm soil depth. • Soil and forest C sequestration could help early anthropogenic CO2 emissions offset. • Improved agronomic practices result in SOC increases that can exceed 0.4% per year. • A 0.4% top soil C increase can lead to yearly grain yield increases (average: 1.3%). • SOC sequestration requires nutrients; from N biofixation or fertilizer recycling. Abstract At the 21st session of the United Nations Framework Convention on Climate Change (UNFCCC, COP21), a voluntary action plan, the '4 per 1000 Initiative: Soils for Food Security and Climate' was proposed under the Agenda for Action. The Initiative underlines the role of soil organic matter (SOM) in addressing the three-fold challenge of food and nutritional security, adaptation to climate change and mitigation of human-induced greenhouse gases (GHGs) emissions. It sets an ambitious aspirational target of a 4 per 1000 (i.e. 0.4%) rate of annual increase in global soil organic carbon (SOC) stocks, with a focus on agricultural lands where farmers would ensure the carbon stewardship of soils, like they manage day-to-day multipurpose production systems in a changing environment. In this paper, the opportunities and challenges for the 4 per 1000 initiative are discussed. We show that the 4 per 1000 target, calculated relative to global top soil SOC stocks, is consistent with literature estimates of the technical potential for SOC sequestration, though the achievable potential is likely to be substantially lower given socio-economic constraints. We calculate that land-based negative emissions from additional SOC sequestration could significantly contribute to reducing the anthropogenic CO 2 equivalent emission gap identified from Nationally Determined Contributions pledged by countries to stabilize global warming levels below 2 °C or even 1.5 °C under the Paris agreement on climate. The 4 per 1000 target could be implemented by taking into account differentiated SOC stock baselines, reversing the current trend of huge soil CO 2 losses, e.g. from agriculture encroaching peatland soils. We further discuss the potential benefits of SOC stewardship for both degraded and healthy soils along contrasting spatial scales (field, farm, landscape and country) and temporal (year to century) horizons. Last, we present some of the implications relative to non-CO 2 GHGs emissions, water and nutrients use as well as co-benefits for crop yields and climate change adaptation. We underline the considerable challenges associated with the non-permanence of SOC stocks and show how the rates of adoption and the duration of improved soil management practices could alter the global impacts of practices under the 4 per 1000 initiative. We conclude that the 4 per 1000 initiative has potential to support multiple sustainable development goals (SDGs) of the 2030 Agenda. It can be regarded as no-regret since increasing SOC in agricultural soils will contribute to food security benefits that will enhance resilience to climate change. However, social, economic and environmental safeguards will be needed to ensure an equitable and sustainable implementation of the 4 per 1000 target. [ABSTRACT FROM AUTHOR]

Highlights • The proportions of macroaggregates were increased under organic practices. • Organic practices increased the water stable aggregates and mean weight diameter. • Organic soil management improved soil microbial biomass and soil enzymes. • Small sized aggregates preserved significantly higher carbon. Abstract Highly weathered laterite soils are a characteristic feature of humid tropics with undulating topography and high rainfall. The crop of cashew (Anacardium occidentale L.) has been cultivated in such landscapes, mainly to prevent further degradation due to the drought hardiness of cashew and requirement of very limited soil disturbances for its cultivation. Providing proper nutrient management is important for balancing the nutrient removal by tree crops especially in poor fertile soils. A study was initiated, after 5 years of application of inorganic fertilisers and organic amendments to cashew in a weathered tropical soil, to evaluate the effects of organic and inorganic sources of nutrients on soil aggregation and biochemical characteristics. The experiment consisted of 11 treatments as Farm Yard Manure (FYM) alone; FYM + biofertiliser consortia; FYM, rock phosphate and wood ash; poultry manure; In situ composting using recyclable cashew biomass and weeds; In situ composting using recyclable cashew biomass and weeds + green manuring; vermicomposting of recyclable cashew biomass; FYM + organic cakes + recyclable cashew biomass + biofertiliser consortia; recommended dose of nitrogen, phosphorus and potassium fertiliser (NPK fertiliser); recommended NPK fertiliser + FYM; and control without nutrient application. Soil samples were collected from surface 0–30 cm layer. The soil samples were fractionated into three aggregate sizes, i.e. , >2 mm (large macroaggregates), 0.25–2 mm (small macroaggregates), 0.053 to 0.25 mm (microaggregates) and <0.053 mm (silt + clay size fraction) using wet sieving. The results indicated that the organic sources of nutrient application increased the proportion of large and small macroaggregates. The treatments receiving only inorganic nutrients and no nutrients contained significantly higher silt + clay fractions (47.7 and 45.5% respectively). A higher percentage of water stable aggregates (47.4–70.7%) and increased aggregate stability (mean weight diameter) (0.78–1.26 mm) was recorded with the application of organic sources of nutrients. Aggregates in the silt + clay size faction and microaggregates recorded significantly higher carbon compared to small and large macroaggregates. Compared to control, the application of different organic amendments increased the soil organic matter (SOM) by 2.2–12.7% in silt + clay size fraction; 14.6–37.0% in microaggregates; 18.4–51.7% in small macroaggregates and 17.7–50.9% in large macroaggregates. Our findings reinforce that the annual application of manures and amendments to weathered tropical soil is important to improve biological properties of soil in terms of soil enzyme activities, microbial carbon and nitrogen, and to prevent further degradation of soil under such fragile environment. [ABSTRACT FROM AUTHOR]

Highlights • EG erosion showed an order of after harvested > before planted > after planted. • EG erosion under different tillage practices were CK＞CT ＞CRT-25＞CRT-40V＞CRT-40S. • Conventional tillage farmlands had to be abandoned since the endless developing of EG. • Tillage practice was the dominant control on EG erosion in the dry-hot valley. Abstract Ephemeral gully (EG) erosion can cause soil loss and result in soil degradation. Appropriate tillage practices are beneficial to soil conservation and avail against soil erosion. Currently, how tillage contributes to soil erosion of EG at the catchment scale is still unclear. To quantify EG erosion and analyze the effects of tillage practice on EG erosion in a typical farmed dry-hot valley catchment, EGs under five tillage practices including conventional tillage (CT), contour ridge tillage in sugarcane land (CRT-40S), vegetable land (CRT-40 V) and in orange land (CRT-25), and without tillage in abandoned land (CK) were investigated. Five field surveys were conducted during two growing seasons from April 2013 to February 2015. The results showed that EG erosion was most serious after crops being harvested, followed by that before crops being planted, after crops being planted subsequently. The average EG erosion modulus of two growing seasons was 231.85 t km−2 a−1. Considering the effect of tillage practices, EG erosion modulus was the largest under CK, followed by CT, CRT-25, CRT-40 V and CRT-40S subsequently, indicating that contour ridge tillage practice would benefit for controlling EG erosion. We found that farmlands with conventional tillage practice had to be abandoned when EGs were developed intensively. But EG erosion did not terminate after being abandoned. The redundancy analysis further confirmed that tillage practice was the dominant control on EG erosion in the dry-hot valley. Our results suggested that appropriate tillage practice such as contour ridge tillage can efficiently restrain EG erosion in the dry-hot valley. [ABSTRACT FROM AUTHOR]

Highlights • Dolomitic limestone (incorporated/surface) had similar correction on soil acidity. • Calcitic corrective provided more effect on soil acidity than dolomitic limestone. • Significant corrective migration is still found twelve years after application. Abstract The main interest of the soils acidity correction is to neutralize the exchangeable Al3+, since the presence of this form of Al in the soil restricts root growth and, consequently, decreases the productivity of sensitive crops. Thus, monitoring the advance of the attributes related to soil acidity in depth in the cultivated areas is fundamental to understand the dynamics of the correction on the surface, helping in the decision-making on the reapplication of the limestones. The aim of this study was to quantify the chemical changes in the soil caused by lime application with different Ca:Mg ratios 141 months after its application. The experiment was installed in 2004 under native field in a Typic Hapludalf. The statistical design was a two-factor type with two types of application forms (incorporated and superficial) and five types of limes (a control and lime with Ca:Mg molar ratios of 35.5 (calcitic), 9.0, 5.0, and 3.2 (dolomitic). In July 2016, 36 trenches were opened in each plot and soil samples were collected at depths of 0–60 cm. In the soil layer of 0–10 cm, the soil samples were collected every 1 cm. In the layer of 10–25 cm, the soil samples were collected every 2.5 cm, and in the layer of 25–60 cm, the samples of were collected every 5 cm. In total, 25 depths per trench were sampled, totaling 828 soil samples used for the chemical analyses. The analysis performed were: values of pH in water in the ratio 1:1, Santa Maria Buffer (TSM) an adaptation of SMP (SchoemakeR et al., 1961), Ca, Mg, and Al exchangeable. The saturation by Al and bases was calculated. Twelve years after the application, the simple deposition of the dolomitic lime on the surface of the soil allowed changes in the attributes related to soil acidity in the profile, changes that were like the incorporation. The use of the calcitic lime provided more significant alterations in the attributes related to soil acidity in the profile compared to the dolomite, given its greater solubility in relation to dolomite. Almost twelve years after the natural acidity correction of the soil following the recommendations of the Soil Chemistry and Fertility Commission -RS / SC (2016), a slight reacidification of the soil of the 0–5 cm layer was observed, whose aluminum saturation is still less than 5% in the first 10 cm. Even almost twelve years after the corrective application, superficial or incorporated, still significant migration of the alkalinizing front in the soil profile to depths greater than 20 cm is seen. [ABSTRACT FROM AUTHOR]

Highlights • Sub-soiling with rotary tillage in wheat season reduced soil penetration resistance. • SR in wheat season promoted soil water usage of 60–140 cm layers. • N-SR promoted the contribution of post-anthesis biomass to grain. Abstract Significant efforts have been made on the assessment of tillage impacts on crop growth during the current season; however, few studies have quantified the impacts on the succeeding crop growth under multiple cropping systems. Based on a multiple-year field experiment under corn-wheat cropping system in North China Plain, therefore, we examined the integrative impacts of annual rotational tillage on wheat growth and soil properties. The annual rotational tillage treatments consisted of two tillage regimes (i.e. N: no-tillage; and SR: sub-soiling with rotary tillage) in the corn season followed by three tillage practices (i.e. sTR: strip rotary tillage; R: rotary tillage; and SR: sub-soiling with rotary tillage) in the wheat season, respectively. The results showed that the N-SR rotational tillage of N in the corn season and SR in the wheat season significantly reduced soil penetration resistance and promoted soil water usage of 60–100 cm soil layers during wheat season. Meanwhile, soil NO 3 −-N concentration in the depth of 40–140 cm was significantly lower under the N-SR than other tillage practices except for the N–R ( P < 0.01 ). Average results of two-year dry matter accumulation and translocation showed that N-SR stimulated wheat biomass production and promoted the contribution of post-anthesis dry matter to the grain ( P < 0.01 ). Consequently, wheat yield was the highest under the N-SR ( P < 0.01 ). Our findings indicate that the annual rotational tillage of no-tillage in the corn season and sub-soiling with rotary tillage in the wheat season can promote wheat growth through enhancing deep soil water and N uptake. [ABSTRACT FROM AUTHOR]

Integrated crop and livestock systems (ICLS) have the potential to minimize soil degradation, improve soil health, and maximize food production. Our goal was to evaluate the impact of no-till (NT) in association with ICLS on soil health and soybean yield in Inceptisol and Oxisol soils in Southern Brazil. The response of physical, chemical, and biological soil health indicators to soil and crop management systems was measured over the short- (<5 years) and long-term (>10 years) under ICLS with soybean in spring/summer and forage grazed by cattle in the autumn/winter. A soil management index was calculated for each soil based on ICLS management. Independent of soil type, ICLS in association with NT for 10+ years improved chemical and biological properties in the near soil surface (0–6 cm depth). The Soil Management Assessment Framework (SMAF) scores for soil organic carbon (SOC), phosphorus (P), and bulk density were close to 1.0 in the Inceptisol, independent of management or soil depth, while the pH scores were lower in the ICLS topsoil. For the Oxisol, the SMAF scores for SOC and P were approximately 1.0 in the 0–6 cm depth under long-term ICLS. The SMAF overall soil quality index was high (approximately 0.9) for both soils and there were no significant differences between management practices. Overall, the adoption of ICLS in association with NT (i) improved or maintained soil health, (ii) promoted soil carbon sequestration, and (iii) increased soybean yield in the studied soils. This study confirmed the potential for conservation practices (ICLS combined with NT) to improve soil quality with environmental sustainability. • Soil compaction increases hydric restrictions and decreases crops yield. • Conservation agricultural practices positively affected soil nutrients. • Integrated crop-livestock systems promote higher stocks of carbon. • Conservation agriculture practices have the potential to maintain or improve soil health. • The overall soil quality index was high under conservation systems. [ABSTRACT FROM AUTHOR]

Crop diversification is a promising strategy to mitigate climate change through soil carbon sequestration while ensuring soil fertility maintenance and food security. Here, we assess the impact of different inter-cropping practices on soil organic carbon (SOC) and nitrogen (N) storage and stabilization under rainfed and irrigated semiarid conditions. Under rainfed conditions, an almond (Prunus dulcis Mill.) monocrop was compared with an almond inter-cropped with caper (Capparis spinosa) or with winter thyme (Thymus hyemalis). Under irrigated conditions, a mandarin (Citrus reticulata Blanco) monocrop was compared with a mandarin inter-cropped with an annual crop rotation (including Hordeum vulgare, Vicia sativa and Vicia faba) or with a triennial crop rotation (including Vicia faba, Portulaca oleracea and Vigna unguiculata L.). The SOC and N stocks, SOC mineralization rates, water-stable aggregates and associated OC and N contents were estimated at 0–10 and 10–30 cm depth in each monocrop and inter-cropping system after three years. Contrasting effects of inter-cropping on SOC and N stabilization were found in the rainfed and irrigated systems. The combination of inter-cropping and no tillage did not affect the SOC stocks or mineralization rates at any soil depth in the rainfed system, while it significantly increased the OC and N contents within the large macro-aggregates in the subsoil. Compared to the irrigated mandarin monocrop, the mandarins inter-cropped with the annual crop rotation showed a significant increase of 10% and 18% in the topsoil and subsoil N stocks, respectively, while the SOC mineralization rates were reduced by 30% at both soil depths. On the contrary, the topsoil SOC stock in the mandarins inter-cropped with the triennial crop rotation were reduced by 38% compared to the monocrop. Significant reductions ranging between 24% and 66% were also observed in the OC and N contents associated to the macro- and micro-aggregates in the topsoil and subsoil of both crop diversifications compared to the monocrop system. Our results highlight the potential of inter-cropping rainfed woody crops with perennials for boosting SOC and N storage and stabilization. In irrigated woody monocrops, inter-cropping with annual crop rotation schemes that include two or more leguminous and reducing tillage frequency operations seems to be more appropriate in terms of SOC and N stabilization. • Inter-cropping rainfed almond trees with perennials fostered subsoil OC and N stabilization. • Inter-cropping irrigated mandarin trees with annual crops hampered SOC and N stabilization at 0–30 cm. • Incorporating legumes when inter-cropping with annual crop rotations is pivotal to foster SOC and N storage. • Minimum tillage and crop residue retention is crucial to preserve and stabilize SOC and N. • Using cover crops as green manure during the first years is pivotal to restore semiarid agricultural soils. [ABSTRACT FROM AUTHOR]

Crop rotation plays an essential role in maintaining soil fertility and is meaningful to soil health and sustainable agricultural management. However, the impact of crop rotational regimes on the soil phosphorus (P) fractions and associated phosphorus cycling (P-cycling) profiles driven by microbial communities are not well elucidated. Hence, we used metagenomics to comprehensively investigate the variations in soil microbial P-cycling functional genes and representative processes, as well their regulations for soil P fractions among distinct crop rotational regimes and complexity. Most soil properties, particularly P fractions, were significantly greater in corn rotations than other crop rotations. The composition of P-cycling functional genes and microbial communities was also distinctly clustered in accordance with crop rotational regimes to varying degrees. The potential of representative P-cycling processes was all significantly higher in the complex rotation. Notably, the key functional genes including phoD, ppx, pstB, ugpA were differently screened from each P-cycling process and assembled toward the middle of their networks. Furthermore, soil potential carbon mineralization as a dominant property regulated several P-cycling processes and was intimately associated with the key P-cycling functional genes. Crop rotational complexity and the P-uptake and transport process had profoundly total effects on soil P fractions. Overall, this study provides a deep insight into soil microbial P-cycling functional profiles for developing sustainable soil P management practices at crop rotational agroecosystems. • Soil P fractions were significantly greater in corn rotations than other crop rotations. • The composition of P-cycling genes was clearly clustered into distinct crop rotational regimes. • Soil PCM could be a dominant property regulating the representative P-cycling processes. • Crop rotational complexity had profoundly total effects on soil P fractions. [ABSTRACT FROM AUTHOR]

Soils with high exchangeable sodium contents have structural and hydrological problems that limit agricultural productivity. Gypsum is commonly applied as an ameliorant but there are few field studies into its long-term (> 10 years) effects on soil chemistry, especially at depths greater than 0.4 m, and no long-term validation of the gypsum requirement model. The aim of this study was to address these two knowledge gaps. This was achieved by a) carrying out a field study of the effects of repeated gypsum applications, irrigation, and sugarcane cultivation to 1.25 m depth over a 26-year period in Australia, and b) assessing the ability of the gypsum requirement model to predict changes in exchangeable sodium percentage (ESP) more broadly, using 53 unique cases from 17 field studies (> 1 year). In our field study, the greatest reductions in exchangeable sodium (up to 5.49 %; p < 0.05) occurred between 0.25 and 1.00 m depth, where initial concentrations were highest. The amount of sodium (16.47 cmol c /m2), magnesium (2.49 cmol c /m2), and potassium (0.65 cmol c /m2) displaced was less than the amount of calcium gained (36.76 cmol c /m2) over the profile. Most calcium was retained in the application layer (0.00–0.25 m) but some moved down to at least 1.25 m. Reductions in exchangeable sodium were smaller than in all previous long-term studies, possibly due to lower deep drainage rates (39–45 mm/year) and increased pH. Assessment of the gypsum requirement model showed that predicted final ESP deviated widely from measured ESP in many cases (95 % of predictions deviated by >10 %), presumably due to interactions between pH, clay type, carbonate, climate, management, and cation exchange equilibria. By adjusting two model parameters, the effect of gypsum on ESP was more accurately predicted (20 % of predictions were within 10 % of measured ESP) making it a useful tool for farmers. • Long-term gypsum use increases exchangeable calcium to 1.25 m depth in dry tropics. • Less exchangeable sodium is lost than expected based on the amount of calcium added. • Low drainage at 1.25 m depth after gypsum and irrigation due to persistent sodicity. • Gypsum requirement model underestimates sodium displacement across diverse regions. • Simple adjustments to the gypsum requirement model significantly improve accuracy. [ABSTRACT FROM AUTHOR]

Tillage and organic fertilization impact short-term soil CO 2 fluxes. However, the interactive effect of these two management practices has been rarely studied under field conditions. The objective of this study was to evaluate the impact of tillage (NT, no-tillage, and CT, conventional tillage) and fertilization strategy (PS, pig slurry, and MF, mineral fertilizer) on short-term soil CO 2 fluxes in a rainfed Mediterranean agroecosystem. Soil CO 2 fluxes were measured several times during two tillage and pre-sowing fertilization periods in 2012 and 2013 (7 and 6 times in 2012 and 2013, respectively). In the two years studied, tillage and fertilization significantly affected soil CO 2 fluxes, but the interaction between both factors was not significant. The application of PS resulted in a sharp and immediate increase in the soil CO 2 flux. One hour after the application of the organic fertilizer, soil CO 2 emissions increased from 0.05 to 0.70 g CO 2  m −2  h −1 and from 0.08 to 0.82 g CO 2  m −2  h −1 in 2012 and 2013, respectively. Unlike fertilization, 1 h after tillage similar soil CO 2 fluxes were observed in CT and NT plots. However, after 7 h, larger fluxes were observed in CT compared with NT in both years. Cumulative CO 2 flux during the first 24 h after fertilization and tillage was about three- and two-fold greater in PS than in MF and in CT than in NT, respectively. The results of this study showed that in rainfed Mediterranean systems, soil management and fertilization have a noteworthy impact on short-term soil CO 2 losses though no interactive effects were observed between both management practices. [ABSTRACT FROM AUTHOR]