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Available water capacity (AWC), field capacity (θFC), and permanent wilting point (θPWP) are regarded as key physical soil health indicators that directly capture the soil's capacity to store plant available water but are expensive components of a comprehensive soil health analysis. To reduce costs, pedotransfer functions for θFC, θPWP, and AWC were developed from a dataset of 7,232 soil samples with texture, soil organic matter (SOM), permanganate-oxidizable carbon, soil respiration, AWC, θFC, θPWP, wet aggregate stability, and extractable potassium, magnesium, iron, and manganese. Three functions were developed for each property: a full random forest (RF) model containing all variables, a reduced RF model and a multiple linear regression model containing texture and SOM. Pedotransfer functions were validated with an independent dataset that contained 1,406 samples. The full RF models for θFC, θPWP, and AWC reduced the root mean square error (RMSE) by 16.3, 13.3, and 12.8%, compared to multiple linear regression models, respectively. Furthermore, the full RF models for θFC, θPWP, and AWC reduced RMSE by 11.6, 6.7, and 12.8%, compared to the reduced RF model, respectively. Permanganate-oxidizable carbon, wet aggregate stability, and extractable magnesium, potassium, and iron were useful novel predictor variables for improving prediction of θFC and AWC. AWC was sensitive in 20/57 long-term experiments, and full RF models were able to replicate 5/20 of those significant results. New RF pedotransfer functions for θFC, θPWP, and AWC can enhance prediction compared to traditional modeling techniques, fits into existing interpretative frameworks, and improves cost-effectiveness of comprehensive assessments of soil health. [ABSTRACT FROM AUTHOR]

Various stakeholders, such as modelers, policy makers, farmers, and environmental regulators need reliable soil bulk density and coarse fragment content data. These two soil parameters are necessary to calculate soil carbon and nutrients stocks, to estimate water availability for plants, or to assess soil compaction. However, measuring these two parameters is labor intensive and time consuming. Therefore, many agricultural and environmental studies often miss these two soil parameters. Here, we provide four datasets, one with bulk density and coarse fragment contents of topsoil and subsoil, measured in two campaigns of the French Soil Quality Monitoring Network (RMQS for its acronym in French), a second one with the average values for bulk density and coarse fragments of the two campaigns at 0–30 cm and 30–50 cm. The third and the fourth ones are the raw data needed to calculate the two first datasets divided by campaign. In addition, the R script for calculating the depth-weighted values per soil layer is provided

This study aims to identify a key soil property influencing farmland prices as a soil production capital indicator for soil security. There is generally a strong relationship between farmland price and production capital, as well as with biomass production. From a soil-centric point of view, under dryland agriculture in Australia, we hypothesise that soil available water capacity (AWC) is a key soil property influencing farmland prices and consequently can act as a soil production capital indicator. Here, we relate soil AWC of Australia to median farmland prices using digital soil maps of AWC. The results revealed that AWC from 0 to 100 cm is significantly associated with farmland prices (r = 0.31, p-value

Generally, soils of arid and semi-arid regions have low water retention properties due to high sand and low organic carbon contents. This study aimed at quantifying the effect of date palm-based organic amendments (OAs) on the water retention properties of two soils (sandy loam and silty loam), as well as the influence of sand supplementation (0.5–2 mm) on the magnitude of the effect of OAs. Different grain size distributions were obtained by adding sand to natural soils. For this purpose, sand was added to the two soils (1/3 and 2/3) and different soil-OA combinations were tested at a dose of 3% by mass: compost alone, biochar alone and a mixture of biochar and compost (50:50 in mass), in addition to unamended control soils. Soil water contents were measured at nine matric potentials ranging from the saturation to the permanent wilting point. Biochar was more efficient than compost at improving soil water retention. The effect of organic amendments on water retention increased with sand content. In most cases, soil water content values were significantly higher for biochar-amended soils than for unamended or compost-amended soils. The weakness of the effect of compost addition (if alone) was probably due to its properties and notably its high mineral content and electrical conductivity. Soil sand supplementation led to higher differences between the OA-amended soils and unamended soils. Changes in available water capacity reached +26% and +80% in a sandy loamy soil enriched with 2/3 sand and amended with compost and with biochar, respectively, compared to the unamended soil. These results show that sand content (and more generally, soil texture) influences the effect of OA application. Thus, the application of biochar from date palm residues in soil seems to be an effective solution to improve the water retention properties of coarse textured soils and contribute to optimizing the use of water resources in irrigated areas. [ABSTRACT FROM AUTHOR]

Generally, soils of arid and semi-arid regions have low water retention properties due to high sand and low organic carbon contents. This study aimed at quantifying the effect of date palm-based organic amendments (OAs) on the water retention properties of two soils (sandy loam and silty loam), as well as the influence of sand supplementation (0.5–2 mm) on the magnitude of the effect of OAs. Different grain size distributions were obtained by adding sand to natural soils. For this purpose, sand was added to the two soils (1/3 and 2/3) and different soil-OA combinations were tested at a dose of 3% by mass: compost alone, biochar alone and a mixture of biochar and compost (50:50 in mass), in addition to unamended control soils. Soil water contents were measured at nine matric potentials ranging from the saturation to the permanent wilting point. Biochar was more efficient than compost at improving soil water retention. The effect of organic amendments on water retention increased with sand content. In most cases, soil water content values were significantly higher for biochar-amended soils than for unamended or compost-amended soils. The weakness of the effect of compost addition (if alone) was probably due to its properties and notably its high mineral content and electrical conductivity. Soil sand supplementation led to higher differences between the OA-amended soils and unamended soils. Changes in available water capacity reached +26% and +80% in a sandy loamy soil enriched with 2/3 sand and amended with compost and with biochar, respectively, compared to the unamended soil. These results show that sand content (and more generally, soil texture) influences the effect of OA application. Thus, the application of biochar from date palm residues in soil seems to be an effective solution to improve the water retention properties of coarse textured soils and contribute to optimizing the use of water resources in irrigated areas.

Crop cultivation on sandy soils is susceptible to water stress. Therefore, we determined the physical-hydric attributes of a Latossolo Vermelho distrófico (Oxisol) in northwestern Paraná state, Brazil. Soil samples were collected at depth ranges of 0 to 0.2 m, 0.2 to 0.4 m, and 0.4 to 0.6 m. We measured clay, silt, sand, fine and coarse sand contents, soil particle density, soil bulk density, total porosity, microporosity, and macroporosity. We also measured soil characteristics such as saturated and unsaturated soil hydraulic conductivities, pore distribution, water retention, available water capacity, and easily available water. We also estimated soil moisture, matric potential at field capacity, and time at field capacity. Validation of associations among these soil physical-hydric attributes was performed using principal component analysis. For the sandy soils analyzed, the distributions of coarse and fine sand fractions were measured for better evaluation of the soil's physical and hydric attributes. Higher coarse sand contents increased soil hydraulic conductivities, maximum pore diameter, and macroporosity while reducing microporosity. Fine sand content reduced conductivity and increased soil water retention in subsurface layers. Simulated sugarcane yield increased with soil water storage. These results support improving crop simulation modeling of sugarcane to support sustainable intensification in regions with sandy soils. [ABSTRACT FROM AUTHOR]

This study examines the soil environment of eight charcoal kiln platforms and the neighboring soil in Czech and Bohemian low-altitude forest stands. Both mixed and undisturbed soil samples were used to assess the hydrophysical soil properties, nutrient content, cation exchange capacity, enzyme activity, and soil active carbon content, while soil color, stoniness, root density, and horizon thickness were estimated in the field. Charcoal-rich horizons had high total organic carbon concentrations and total nitrogen content (about 150% and 40% higher than in the organomineral horizons of the control plot, respectively), with total carbon stocks being higher than those in neighboring forest soils. Fine root density was highest in the charcoal-rich horizons, encouraged by high soil porosity, aeration, and favorable chemical properties. Enzyme group activity differed between individual soil horizons and kiln and control plots, with depolymerization enzyme activity highest in charcoal-rich horizons and humification enzyme activity highest in mineral horizons. Phosphatase, chitinase, and phenoloxidase activity were highest in charcoal-rich horizons, while β-glucosidase activity remained similar across horizons. After long-term abandonment, kiln sites shift from inhospitable sites to localized hotspots for plant and microbial growth, having more favorable physical, enzymatic, and chemical soil properties than the surrounding areas. This study confirmed that kiln production platforms act as microhabitat hotspots, also providing information on a wide spectrum of soil properties linked with soil microorganisms and root growth. [ABSTRACT FROM AUTHOR]

Soil available water capacity (AWC) and bulk density (BD) are key properties for understanding water flows in soils, land‐use planning and irrigation management. As measuring these properties is costly and time‐consuming, pedotransfer functions (PTFs) are commonly used to predict BD and soil moisture at a specific matric potential and then estimate AWC. Currently, operational tools to estimate AWC at the soil profile scale from data easily available are lacking. In this study, new PTFs based on the regression‐tree method Cubist were developed at a regional scale to predict soil water contents at −10 kPa (field capacity) and −1585 kPa (permanent wilting point), and BD. A first PTF (PC model) required commonly measured soil properties (sand, silt, clay, organic carbon contents), while the second (PM model) required four additional predictors: qualitative information deriving from description of the soil profile. The models were validated with an independent dataset. Both models outperformed existing PTFs. AWC was then estimated at the horizon scale, soil‐profile scale and in the upper 30 cm of soil. The PM model performed better than the PC model with the training dataset at the profile scale (Nash‐Sutcliffe efficiency = 0.87 and 0.60; RMSE = 0.186 and 0.326 mm cm−1, respectively). Independent validation of AWC estimates at the profile scale by the PM and PC models yielded RMSE of 0.192–0.204 and 0.229–0.244 mm cm−1, respectively. The sensitivity of AWC to estimates of soil depth and coarse‐fragment content was tested. Results confirmed the importance of these variables resulting in soil observation to estimate AWC accurately. [ABSTRACT FROM AUTHOR]

Integrated crop-livestock systems (ICLS) can mitigate the impacts of cropping intensification by improving soil organic carbon (SOC) and associated hydro-physical properties. This study was conducted on three on-farm long-term (≥30 years) sites (Site 1, 2, and 3) and one short-term (4 years) experimental site (Site 4) to compare the SOC and hydro-physical properties to a depth of 40 cm for an intensive-cropland (CL), a native-grassland (NG) and cropland managed with ICLS. Data showed higher SOC, soil water retention (SWR), macroporosity, available water capacity (AWC), and saturated hydraulic conductivity (K sat) for the NG than the CL indicating the degradation of soil physical quality because of intensive agriculture. However, for sites 1 and 2, the ICLS had 27% and 46% more SOC than the CL in the 0–10 cm depth. In addition, the ICLS decreased bulk density (ρ b) (sites 1 and 3) and increased the K sat (sites 1, 2, and 3) at 0–10 cm depth as compared to the CL. No differences in SOC or hydro-physical properties were observed for the short-term ICLS (site 4) when compared to the CL. The impacts of ICLS were most prominent at the surface soil (0–10 cm) and no difference was observed for the deeper soil. The AWC showed a linear increase with the increase in SOC, however, soils under ICLS and CL showed a higher increase in AWC with an increase in SOC as compared to the NG. This study highlighted the negative impacts of grassland to cropland conversion and suggested the implementation of ICLS to improve organic carbon and other associated hydro-physical properties of soils. • Conversion of grassland to cropland (CL) reduced soil organic carbon (SOC). • Long-term crop-livestock grazing (ICLS) improved SOC for surface soil. • The impacts of ICLS on soil hydro-physical properties and SOC varied with the depth. • Available water capacity increased with the increase in SOC under ICLS and CL. [ABSTRACT FROM AUTHOR]

Brazilian soybean has undergone considerable economic growth. Its production depends on the demand for some inputs. One of these inputs is the soil water supply, which can be made artificially or obtained by natural rainfall. Knowledge of available water capacity (AWC), which depends on total water availability (TWA), is poorly accessible and difficult to measure in the field. This study aimed to map the AWC of the state of Tocantins, based on pedotransfer functions (PTFs), to evaluate the water availability of the soils of the microregions of that state. We used the Arya and Paris model, aided by a computer program, Qualisolo, made by Embrapa Instrumentação. One hundred fifty-seven tropical soil samples were extracted from the Embrapa Solos portal. Preliminarily, the soil water retention curve (SWRC) was obtained and, subsequently, the TWA and AWC for this oilseed were estimated. Multiple linear regressions show the correlation between TWA and clay (CL), Silt (ST) and total sand (TS) contents. The correlation established was TWA = 3.2993 – 0.0028TS – 0.0034CL. This main conclusion reflects a fruitful AWC for decision-making by the soybean agribusiness and exposes the regional weaknesses for this crop under a rainfed regime in some regions of Tocantins. We could observe that, in terms of water availability, agribusiness is a potential threat to the environment protection area (APA) of the Ilha do Bananal/Cantão, Formoso River microregion.

Abstract The objective of this work was to determine pedotransfer functions to predict water retention at the -33 and -1500 kPa matric potentials of soils under Cerrado, in the south of the state of Mato Grosso, Brazil. Samples (n=156) were collected for model calibration (n=124) and validation (n=32). A stepwise multiple regression was used to determine pedotransfer functions. Willmott’s index of agreement, root-mean-square error, Pearson’s correlation coefficient, and the confidence index were used to evaluate the performance of the functions and to compare them with those described in the literature. The most efficient variables to estimate water retention were: microporosity, total sand, and clay at -33 kPa; and total sand, silt and clay at -1500 kPa. The regional pedotransfer functions explained more than 94% of water retention variance in the studied soils. The reliability of the functions to predict water retention increased, at -33 kPa, with the use of the structural property microporosity and, at -1500 kPa, with the use of granulometric parameters. The studied regional pedotransfer functions predict water retention at the -33 and -1500 kPa matric potentials of soils under Cerrado, in southern Mato Grosso, better than the functions described in the literature.

Crop cultivation provides ecosystem services on increasingly large fields. However, the effects of in-field spatial heterogeneity on crop yields, in particular triticale, have rarely been considered. The study assess the effects of in-field soil heterogeneity and elevation on triticale grown in an intensively cropped hummocky landscape. The field was classified into three soil classes: C1, C2, and C3, based on soil texture and available water capacity (AWC), which had high, moderate, and low yield potential, respectively. Three elevations (downslope (DS), midslope (MS), and upslope (US)) were considered as the second study factor. An unbalanced experimental design was adopted with a factorial analysis of variance for data analysis. Temporal growth analysis showed that soil classes and elevation had significant effects. Generally, better growth was observed in C1 compared to that of C3. DS had a lower yield potential than that of MS and US. In addition, the interactive effect was confirmed, as triticale had poor growth and yield in C3 on the DS, but not on US. Crop physiological parameters also confirmed the differences between soil classes and elevation. Similarly, soil moisture (SM) content in the plow layer measured at different points in time and AWC over the soil profile had a positive association with growth and yield. The results confirmed that spatial differences in AWC and SM can explain spatial variability in growth and yield. The mapping approach combining soil auguring techniques with a digital elevation model could be used to subdivide fields in hummocky landscapes for determining sub-field input intensities to guide precision farming. [ABSTRACT FROM AUTHOR]

Appropriate soil amendments may increase plant available water and crop yields on coarse sandy soils under drought conditions. In this study, we applied straw ash or straw biochar from gasification to a Danish coarse sandy subsoil to assess the effects on soil water retention, evapotranspiration and crop yields. Spring barley (2016, 2017) and winter wheat (2018) were grown over three years in columns containing 25cm of organic matter‐rich topsoil, 80 cm of amended coarse sandy soil (1.5%, 3%, 6% wt. ash or 1% wt. biochar or control soil) and 45 cm of un‐amended subsoil. Precipitation, evaporative demands and soil moisture were recorded across the growth seasons, with 2018 having severe drought conditions. This year evapotranspiration levels increased with increasing ash and biochar content (by 54% and 33% for the 6% ash‐ and 1% biochar‐amended soils, respectively), and plant dry matter increased by 18% in both the 1% biochar‐ and 6% ash‐treated soils compared to the untreated control. A linear relationship was established between in situ field capacity and ash dosage (R2 =.96), showing an increase of 2.2% per percentage (wt.) of ash added, while the 1% biochar treatment increased the capacity by 3.5%, indicating a higher efficiency than for ash. However, we did not find significant positive effects on grain yields. The results show that ash and biochar have the potential to significantly increase soil water retention, evapotranspiration and total dry matter yield in drought conditions, but that this may not correspond to an increase in grain yield. [ABSTRACT FROM AUTHOR]

Effects of different cover crops on soil quality parameters and yield of an apple orchard located in Develi town of Kayseri province of Turkey were investigated in this study. Trifolium repens L. (TR), Festuca rubra subsp. rubra (FRR), Festuca arundinacea (FA), T. repens (40%) + F. rubra rubra (30%) + F. arundinacea (30%) mixture (TFF), Vicia villosa (VV) and Trifolium eneghinianum (TM) were used as the cover crops in an apple orchard with sandy loam soil. Experiments also included plots mechanically cultivated (MC), herbicide treatment (HC) and control (C) plot without cover crops. Soil samples were taken from two different depths (0-20 and 20-40 cm) in each plot. Experiments were conducted in randomized complete blocks design with four replications. The cover crop treatments improved soil quality parameters like organic matter (OM), basal soil respiration, bulk density (BD), aggregate stability, saturated hydraulic conductivity (Ks), available water capacity compared to the soil of a nontreated control plot. Mean OM contents at 0-20 cm soil depth was ordered as; HC (0.56%)

Soil moisture has been a key limiting factor for crop growth during the surface process in many lands. It is very necessary to establish the placement criteria of monitoring sites for the soil moisture in optimum irrigation. The spatial and temporal distribution of Available Water Capacity (AWC) was strongly correlated with soil moisture. The AWC spatial distribution pattern was also related to soil characteristics, but it can be more stable than that of soil moisture. In this study, a spatially stratified sampling was proposed to relieve the strong temporal and spatial variability, when the soil moisture was used as a variable. The Stratified Sampling method based on spatial autocorrelation of Auxiliary Variables (SSAV) was also used to combine the classical statistics and geo-statistics, where the AWC was introduced as an auxiliary variable. The experiments were then carried out to verify at a field scale. The results showed that the AWC in the 0-40 and 0-80 cm soil layers followed the normal distribution, indicating a moderate variation. In the 90% confidence interval, the number of monitoring points in the 0-40 and 0-80 cm soil layers in the study area was 7 and 6, respectively, where the sampling error was 10%, indicating that the reducing number of monitoring points, and cost-saving monitoring of soil moisture. The geostatistical analysis demonstrated that the range of two soil layers (0-40 and 0-80 cm) was both 366 m in the semi-variance function of AWC. The relative errors of soil moisture estimated by the Simple Random Sampling (SRS) and SSAV were –27.03%-52.38%, and –23.23%-35.15%, respectively. The relative error of soil moisture estimated by the SSAV was reduced by 26.48%, compared with the SRS. The mean standard deviation was 4.78%, 17.30% lower than that of SRS. A paired t-test indicated that the relative error and the mean standard deviation of soil moisture were 9 times in the two soil layers under two monitoring during 2016-2018. Thus, there were significant differences between the relative error range and the mean standard deviation under two monitoring (P<0.001). Moreover, the uncertainty of SSAV was reduced significantly, whereas, the estimation accuracy was improved significantly, compared with the SRS. Among them, the uncertainty of SRS was attributed to the independent samples that followed the normal distribution. There was also a certain spatial change of soil characteristics at a certain scale, indicating a spatial correlation. Correspondingly, the larger deviation of estimation accuracy was attributed to the SRS model without considering the spatial autocorrelation of soil moisture. The Root Mean Square Error (RMSE) between the observed and estimated values was only 0.010 4 cm3/cm3, indicating significantly lower than that of the SRS (0.012 0 cm3/cm3). As such, the uncertainty of sampling was reduced according to the value range of AWC. The new sampling was fully considered the influence of the spatial structure of the target variable on the layout of monitoring points. Specifically, the distance between any two monitoring points was required to be greater than the range, where the monitoring points were independent of each other. Therefore, the estimation accuracy and precision of soil moisture were improved, compared with the SRS. Consequently, the SSAV can be widely expected to serve a time-, labor- and cost-saving monitoring scheme for the average soil moisture. The finding can provide a promising guideline for water resources management and water use efficiency in modern agriculture. [ABSTRACT FROM AUTHOR]

Soils provide the structural support, water and nutrients for plants in nature and are considered to be the foundation of agriculture production. Improving soil quality and soil health has been advocated as the goal of soil management toward sustainable agricultural intensification. There have been renewed efforts to define and quantify soil quality and soil health but establishing a consensus on the key indicators remains difficult. It is argued that such difficulties are due to the former ways of thinking in soil management which largely focus on soil properties alone. A systems approach that treats soils as a key component of agricultural production systems is promoted. It is argued that soil quality must be quantified in terms of crop productivity and impacts on ecosystems services that are also strongly driven by climate and management interventions. A systems modeling approach captures the interactions among climate, soil, crops and management, and their impacts on system performance, thus helping to quantify the value and quality of soils. Here, three examples are presented to demonstrate this. In this systems context, soil management must be an integral part of systems management practices that also include managing the crops and cropping systems under specific climatic conditions, with cognizance of future climate change.

Effects of different cover crops (CCs), mechanically cultivation and herbicide treatments on soil organic matter (SOM) content and some physical properties of soils were investigated in a cherry orchard with clay soil in 2013 and 2014. The present study was conducted in a cherry orchard located at the Experiment Station of Black Sea Agricultural Research Institute in Samsun province in the Northern region of Turkey. As the CCs, Trifolium repens L. (TR), Festuca rubra subsp. Rubra (FRR), Festuca arundinacea (FA), T. repens (40%)+F. rubra rubra (30%)+F. arundinacea (30%) mixture (TFF), Vicia villosa (VV) and Trifolium meneghinianum (TM) were utilized. Experiment also included plots mechanically cultivation (MC), herbicide treatment (HC) and control (C) plot without CCs. Experiment was conducted in randomized complete blocks design with four replications. The CCs were mowed in the flowering period of the plants. After 90 d following seed harvest, soil samples were collected from two depths (0-20 and 20-40 cm) in each plot. The CCs treatments decreased bulk density, volumetric water content, relative saturation, penetration resistance and increased SOM, field capacity, permanent wilting point, available water capacity, total porosity, gravimetric water content, mean weight diameter, structural stability index. The differences in the SOM contents and physical soil properties of all treatments as compared to the control were not found to be significant for the 20-40 cm soil depth in both years of experiments. The CCs, especially TR and VV treatments as legume plants improved SOM and physical soil properties, but longer term studies are needed to evaluate the long-term effects.

Various stakeholders, such as modelers, policy makers, farmers, and environmental regulators need reliable soil bulk density and coarse fragment content data. These two soil parameters are necessary to calculate soil carbon and nutrients stocks, to estimate water availability for plants, or to assess soil compaction. However, measuring these two parameters is labor intensive and time consuming. Therefore, many agricultural and environmental studies often miss these two soil parameters. Here, we provide four datasets, one with bulk density and coarse fragment contents of topsoil and subsoil, measured in two campaigns of the French Soil Quality Monitoring Network (RMQS for its acronym in French), a second one with the average values for bulk density and coarse fragments of the two campaigns at 0-30 cm and 30-50 cm. The third and the fourth ones are the raw data needed to calculate the two first datasets divided by campaign. In addition, the R script for calculating the depth-weighted values per soil layer is provided., (© 2024 The Authors.)

This study examines the soil environment of eight charcoal kiln platforms and the neighboring soil in Czech and Bohemian low-altitude forest stands. Both mixed and undisturbed soil samples were used to assess the hydrophysical soil properties, nutrient content, cation exchange capacity, enzyme activity, and soil active carbon content, while soil color, stoniness, root density, and horizon thickness were estimated in the field. Charcoal-rich horizons had high total organic carbon concentrations and total nitrogen content (about 150% and 40% higher than in the organomineral horizons of the control plot, respectively), with total carbon stocks being higher than those in neighboring forest soils. Fine root density was highest in the charcoal-rich horizons, encouraged by high soil porosity, aeration, and favorable chemical properties. Enzyme group activity differed between individual soil horizons and kiln and control plots, with depolymerization enzyme activity highest in charcoal-rich horizons and humification enzyme activity highest in mineral horizons. Phosphatase, chitinase, and phenoloxidase activity were highest in charcoal-rich horizons, while β-glucosidase activity remained similar across horizons. After long-term abandonment, kiln sites shift from inhospitable sites to localized hotspots for plant and microbial growth, having more favorable physical, enzymatic, and chemical soil properties than the surrounding areas. This study confirmed that kiln production platforms act as microhabitat hotspots, also providing information on a wide spectrum of soil properties linked with soil microorganisms and root growth.

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The livestock sector contributes about 40% of global agricultural output and uses over 30% of total feed-crop land. The sector's continuing growth has led to increased technology and larger-scale, commercialized agriculture, and it correlates to growth in by-products and waste, which can compromise the environment and human health. Although organic manure is an excellent soil fertilizer whose nutrient content increases crop yield, untreated and/or overapplied manure pollutes local water resources and can alter soil aggregate structure, potentially affecting soil health and available water. Proper livestock waste management is essential for sustainable food production. Waste reuse strategies exist, with goals such as minimizing freshwater consumption, improving food production, and contributing to energy production, However, each strategy has tradeoffs in environmental, energy, or monetary costs. This study provides a quantitative approach to evaluating waste impact on soil health and helps to better manage irrigation practices and water supply gaps in arid and semi-arid areas by better understanding how management practices affect physical soil health. The TypoSoil apparatus was used to measure and analyze the hydrostructural parameters (water-holding capacity and soil structure) of fine sandy loam (A horizon) and sandy clay (B horizon). Soils from the Texas A&M AgriLife Research Dairy (Stephenville, Texas) were collected and compared with control (untouched) soils. Waste (manure, bedding materials, wash water) was separated into liquid (passed through a natural lagoon treatment process) and solid components (applied as fertilizer). Approximately half the wastewater was reused as wash water, the remainder for irrigation. Although the soil varied substantially between sample locations, a statistically significant difference existed between the control and manure/wastewater applications in both the A and B horizons. Both applications improved plant-available water (AW) in the A horizon (40% and 30%, respectively) but deteriorated AW in the B horizon (25% and 30%). Thus, dairy farm waste is a viable source for agricultural use. [ABSTRACT FROM AUTHOR]

Biochar (BC) is used as a soil amendment to enhance plant growth by improving mainly soil chemical and hydrophysical properties. In this work the effects of two types of BCs on soil water retention properties were analysed. The first type of BC was made from sugarcane bagasse. It was added to a clay "Shimajiri Maji" soil at an application rate of 3 w%. The second type of BC was made from paper fiber sludge and grain husks. It was added into a loam soil at rates of 3.6, and 7.3 w%. It was assumed that the effect of BC amendment will be more pronounced in coarse-grained soil than in fine-grained one. Therefore, the second type of BC was applied additionally in the silica sand, in a textured contrast material compared with the loam soil. The BC amendment caused statistically significant increase of water content in the transmission pores of the clay soil, in the storage pores of the loam soil, and in the macropores and the storage pores in the silica sand. Despite of the positive effect on soil water retention, statistically significant increase of available water capacity (AWC) was identified only in the loam soil with the larger BC amendment rate. Possible reasons are discussed.

The positive effect of soil organic matter (SOM) on crop yield has historically been attributed to the ability of SOM to supply crops with nitrogen and water. Whether management-induced increases in SOM meaningfully supplement water supply has received recent scrutiny, introducing uncertainty to the mechanisms by which SOM benefits crops. Here, we posit that to benefit crops SOM does not need to increase the supply of a growth-limiting resource; it only needs to facilitate root access to extant resource stocks. We highlight evidence for the ability of SOM to alleviate negative impacts of inadequate aeration (mainly waterlogging) and compaction on roots. Waterlogging, even if transient, can permanently downregulate root biosynthesis and call for expensive growth of new roots. Management practices that promote SOM reduce waterlogging by accelerating water infiltration and may promote aeration in non-saturated soils. Compaction as a restriction to root development manifests in drying soils, when mechanical impedance (MI) inflates photosynthate required to extend root tips, leading to short, thick, and shallow roots. SOM reduces MI in dry soils and is associated with root channels to subsoil, granting crops access to deep soil water. Both waterlogging and compaction necessitate additional belowground investment per unit resource uptake. In this framework, crop response to SOM depends on interactions of crop susceptibility to inadequate aeration or compaction, soil moisture, and “baseline” soil aeration and compaction status. By exploring the proposition that SOM catalyzes resource uptake by permitting root development, future research may constrain crop yield improvements expected from SOM management.

Effects of different cover crops on soil quality parameters and yield of an apple orchard located in Develi town of Kayseri province of Turkey were investigated in this study. Trifolium repens L. (TR), Festuca rubra subsp. rubra (FRR), Festuca arundinacea (FA), T. repens (40%) + F. rubra rubra (30%) + F. arundinacea (30%) mixture (TFF), Vicia villosa (VV) and Trifolium meneghinianum (TM) were used as the cover crops in an apple orchard with sandy loam soil. Experiments also included plots mechanically cultivated (MC), herbicide treatment (HC) and control (C) plot without cover crops. Soil samples were taken from two different depths (0-20 and 20-40 cm) in each plot. Experiments were conducted in randomized complete blocks design with four replications. The cover crop treatments improved soil quality parameters like organic matter (OM), basal soil respiration, bulk density (BD), aggregate stability, saturated hydraulic conductivity (Ks), available water capacity compared to the soil of a nontreated control plot. Mean OM contents at 0-20 cm soil depth was ordered as; HC (0.56%)

Effects of different cover crops (CCs), mechanically cultivation and herbicide treatments on soil organic matter (SOM) content and some physical properties of soils were investigated in a cherry orchard with clay soil in 2013 and 2014. The present study was conducted in a cherry orchard located at the Experiment Station of Black Sea Agricultural Research Institute in Samsun province in the Northern region of Turkey. As the CCs, Trifolium repens L. (TR), Festuca rubra subsp. Rubra (FRR), Festuca arundinacea (FA), T. repens (40%)+F. rubra rubra (30%)+F. arundinacea (30%) mixture (TFF), Vicia villosa (VV) and Trifolium meneghinianum (TM) were utilized. Experiment also included plots mechanically cultivation (MC), herbicide treatment (HC) and control (C) plot without CCs. Experiment was conducted in randomized complete blocks design with four replications. The CCs were mowed in the flowering period of the plants. After 90 d following seed harvest, soil samples were collected from two depths (0-20 and 20-40 cm) in each plot. The CCs treatments decreased bulk density, volumetric water content, relative saturation, penetration resistance and increased SOM, field capacity, permanent wilting point, available water capacity, total porosity, gravimetric water content, mean weight diameter, structural stability index. The differences in the SOM contents and physical soil properties of all treatments as compared to the control were not found to be significant for the 20-40 cm soil depth in both years of experiments. The CCs, especially TR and VV treatments as legume plants improved SOM and physical soil properties, but longer term studies are needed to evaluate the long-term effects. [ABSTRACT FROM AUTHOR]

Effects of different cover crop treatments, mechanical cultivation and herbicide treatment on soil quality parameters and yield of a hazelnut orchard located in Samsun province of Turkey were investigated. Festuca rubra subsp. rubra (FRR), Trifolium repens (TR), Festuca arundinacea (FA), T. repens (40%) + F. rubra rubra (30%) + F. Arundinacea (30%) mixture (TFF), Vicia villosa (VV) and Trifolium meneghinianum (TM) cover crops were used in a hazelnut orchard with clay loam soils. Experiments also included mechanical control (MC), herbicide control (HC) and bare control (BC) treatments. Soil samples were taken from two depth (0-20, 20-40 cm) to analyses for soil quality parameters. It was observed that cover crops improved soil quality variables at the 0-20 cm soil depth. Cover crop applications rised the organic matter (OM) content from 2.28% for bare soil to 3. 64 % for the VV application. Rises in OM content due to different cropping regimes were obtained in the following order: HC< BC< MC< FA< FRR< TM< TFF< TR< VV. VV application compared with the other applications determined the highest rises in OM (59.7%), total porosity (10.9% ), saturated hydraulic conductivity (161.2% ), aggregate stability (9.9%), electrical conductivity (68.6%) and the largest decrease in bulk density (11.7%). While the highest mean hazelnut yield (1516 kg ha-1) was found in the VV, the lowest mean hazelnut yield (1337 kg ha-1) was obtained with in the MC. Cover crops, especially VV and TR treatment, may be incorporated into cropping systems to improve soil quality variables and hazelnut yield. [ABSTRACT FROM AUTHOR]

This study mainly focused on the impacts of vermicompost (VC) treatments on physicochemical characteristics of sandy-clay-loam soil and lettuce (Lactuca sativa var. crispa) yield in a greenhouse under different soil moisture regimes. Pot experiments were conducted with different VC treatment doses (0%, 2.5%, and 5% w/w) and three soil water regimes (100%, 50%, and 25%Ɵf, Ɵf is field capacity). Following the harvest, soil samples were taken and analyzed for physicochemical properties. The highest organic matter content (2.19%) was observed in 5% VC treatment of the full irrigation level (100%Ɵf) irrigation treatment and the lowest organic matter content (0.19%) was obtained from the control treatment of the lowest irrigation level (25%Ɵf). Soil physical properties were positively influenced by VC treatments under different irrigation regimes. The highest lettuce yield (178.7 g plant−1) was observed in 5% VC treatment of the full irrigation level (100%Ɵf) irrigation treatment and the lowest lettuce yield (94.0 g plant−1) was obtained from the control treatment of the lowest irrigation level (25%Ɵf). Present findings revealed that vermicompost treatments under different irrigation regimes could reliably be used to enhance soil physicochemical properties and lettuce yield. [ABSTRACT FROM AUTHOR]

Biochar application to agricultural soils has been proposed as a way to increase crop production by improving soil chemical and physical properties. Liming potential and improved nutrient exchange on biochar surfaces are the most reported mechanisms. Wherever crops experience drought stress, improvements in soil water holding capacity (WHC) might also be an important mechanism. However, reported effects on soil structure and WHC are mixed. Therefore, we studied the effects of biochar on soil bulk density (BD) and WHC in a laboratory column study using two agricultural soils from Portugal: a sandy and a sandy loam soil. Mixed woody feedstock was pyrolysed at 620 °C, creating a wettable biochar that was used unsorted as well as sieved into large (2–4 mm) and small (0.05–1.00 mm) particles, mixed into the soils at 1, 5, 10 and 20% (by volume), and incubated for 10 days at field capacity to allow aggregation. Soil samples were analysed for BD and WHC using soil columns. We found biochar to decrease soil BD and increase maximum WHC, expressed as gravity-drained equilibrium water content, for both soils. The sandy soil was more responsive with significant effects at the lowest application rate (1%), while the sandy loam soil started to show significant effects at 5% biochar. Small biochar particles reduced the BD of sandy soil more, while large biochar particles caused a greater reduction in the BD of the sandy loam soil. The effect of biochar particle size on WHC was less clear, except for small particles at 20% volumetric concentration, which showed a 60% increase in gravimetric WHC. When expressed as total soil water storage (SWS), 20% biochar incorporation to 15 cm depth would increase the total SWS of sandy soil from 0.56 mm (control) to 0.83–0.91 (mm), and of the sandy loam soil from 0.56 to 0.79–0.96 (mm), depending on biochar particle size. Our results suggest that biochar particle sizes can be used to achieve specific effects in soils, while mechanisms and trade-offs (agro-economic and environmental) need further exploration. Unlabelled Image • Small biochar particles reduced bulk density more for sandy than sandy loam soil. • Large biochar particles reduced bulk density more for sandy loam than sandy soil. • Small particles at 20% increased gravimetric water holding capacity by 60%. • The total soil water storage of sandy soil increased from 56 to 83–91 (mm). • The total soil water storage of sandy loam soil increased from 56 (mm) to 79–96 (mm). [ABSTRACT FROM AUTHOR]

Quantifying soil water storage is important for plant growth and agricultural production. This is particularly important in sandy soils because they are widely cultivated and prone to drought. We investigated the effect of soil organic carbon (SOC), soil texture and gravel content on soil moisture characteristics in sandy soils. Soil moisture characteristics were analysed using standard soil physical characterization as well as visible–near infrared (vis–NIR) spectroscopy and pedotransfer functions (PTFs). Volumetric water content (−10, −33, −1500 kPa) and available water capacity (AWC) increased by 0.01 to 0.02 m3m−3 with a 2% increase in silt plus clay content. Available water capacity increased by about 0.05 m3m−3 with a 1% increase in SOC. A 5% increase in gravel in the subsoil decreased the volumetric water content of the soil by 0.01 m3m−3. Predictions of volumetric water contents and AWC by vis–NIR were the best when using a random forest model. Pedotransfer functions for AWC predictions performed best when sand, silt, clay, bulk density and SOC were included. Soil moisture storage ranged from 44 to 65 mm in the top 50 cm. At mean evapotranspiration (4.2 mm day−1), irrigation requirements were reduced by 6 days in the sandy soils that have larger SOC and silt contents in the topsoil. These soils are sandy throughout but have subtle differences in particle‐size distribution, SOC concentrations and gravel content. These differences affect soil moisture storage considerably. Soil management practices that increase the SOC contents in these sandy soils favour moisture storage and tend to reduce irrigation requirements. Highlights: SOC, soil texture and gravel affect soil moisture characteristics in sandy soils.With vis–NIR and PTFs, soil water storage, water characteristics and AWC in soils with >80% sand can be quantified and predicted.Available water capacity increased by about 0.05 m3m−3 with a 1% increase in SOC.Subtle differences in particle‐size distribution affect soil moisture storage and reduce irrigation requirements. [ABSTRACT FROM AUTHOR]

Biochar (BC) is used as a soil amendment to enhance plant growth by improving mainly soil chemical and hydrophysical properties. In this work the effects of two types of BCs on soil water retention properties were analysed. The first type of BC was made from sugarcane bagasse. It was added to a clay "Shimajiri Maji" soil at an application rate of 3 w%. The second type of BC was made from paper fiber sludge and grain husks. It was added into a loam soil at rates of 3.6, and 7.3 w%. It was assumed that the effect of BC amendment will be more pronounced in coarse-grained soil than in fine-grained one. Therefore, the second type of BC was applied additionally in the silica sand, in a textured contrast material compared with the loam soil. The BC amendment caused statistically significant increase of water content in the transmission pores of the clay soil, in the storage pores of the loam soil, and in the macropores and the storage pores in the silica sand. Despite of the positive effect on soil water retention, statistically significant increase of available water capacity (AWC) was identified only in the loam soil with the larger BC amendment rate. Possible reasons are discussed. [ABSTRACT FROM AUTHOR]

Abstract Soil available water capacity is an important soil property for land use planning, drought risk assessment, and modelling crop production or carbon cycling. Measurements of soil moisture at several soil water potentials are expensive and time-consuming, hence it is common to estimate available water capacity with pedotransfer functions (PTFs). Available PTFs for France rarely provide uncertainty estimates for the model coefficients and predictions, which are often required for error propagation analysis and modelling ecological processes. The objectives of this study were: 1) to develop class-PTFs and 2) continuous-PTFs with associated uncertainties, and 3) to assess the domain of applicability of the PTFs across metropolitan France. We used the SOLHYDRO database for calibrating continuous and class PTFs. For continuous PTFs we used linear regression models using sand, clay, organic carbon (SOC), and bulk density (BD) as predictor variables, whereas class-PTFs were defined by texture class, bulk density, and horizon type (all horizons, topsoils, subsoils). The models were validated with an independent validation dataset. The domain of applicability of the PTFs was evaluated calculating the Mahalanobis distance between the calibration dataset and horizon data from the French soil monitoring network (RMQS). At independent validation, texture class-PTFs had a RMSE between 0.047 cm3 cm–3 and 0.058 cm3 cm–3 and continuous-PTFs had a RMSE between 0.040 cm3 cm–3 and 0.053 cm3 cm–3. Texture class-PTFs had similar or better predictive performance than texture-structural class-PTFs. The prediction performance of continuous-PTFs improved slightly when including SOC and BD in the models. The variance of the predictions of continuous-PTFs associated to error in the model coefficients was rather small, and increased as the values of the predictor variables were more distant to the centroid of the calibration data. We provide the PTF users with tools for classifying new samples as within or outside the applicability domain of the PTFs. When applied to the RMQS dataset, >50% of the horizons outside the domain of applicability were located in forests and natural areas or managed pastures. The spatial distribution of RMQS horizons outside the domain of applicability of the PTF can inform future sampling locations for increasing the diversity of the soil properties and site conditions represented by the SOLHYDRO dataset. Highlights • We calibrated class and continuous-PTFs for estimating soil moisture at pF = 2.0 and pF = 4.2 • RMSE ranged between 0.040 cm3 cm−3 and 0.058 cm3 cm−3 at independent validation • The PTFs are suitable for estimating available water capacity in most agricultural French soils • Users can assess whether their samples are within the applicability domain of the PTFs [ABSTRACT FROM AUTHOR]

[Display omitted] • The main factor that increased AWC was the reduction of PWP in medium-textured soils. • The long-term effect of biochar on AWC was strongest in fine-textured soils. • FC was not always the main driver of AWC increase under biochar treatment. Biochar has been widely applied as a soil modifier to improve the physical properties and increase the water content of the soil. Although the response of soil hydrological properties to biochar has been extensively studied, the effect of biochar on soil hydrological properties in different soil textures has not been comprehensively quantified. Here, we performed a meta-analysis of 939 observations to quantify the effects of biochar on the water retention capacity of soil with different textures. The effect of biochar on field capacity (FC) and available water capacity (AWC) of the soil was greater in coarse-textured soils (23.8%, 25.6%) than those in medium- (5.0%, 20.9%) and fine-textured soils (7.2%, 11.5%). The permanent wilting point increased in coarse-textured soils (19.9%), decreased in medium-textured soils (−4.2%), and did not change considerably in fine-textured soils as affected by biochar. We demonstrated that FC is not always the main driver of increased AWC. In coarse-textured soils, there is a high correlation between hydrological properties. In addition, the specific surface area, surface functional groups, and cation exchange capacity of biochar are important factors affecting the water retention of soils with different textures. Our study establishes that the differences in soil texture cause heterogeneity in the mechanisms by which biochar improves soil water retention. [ABSTRACT FROM AUTHOR]

Among potential components to construct Technosols for urban greening purposes, the commercially available geogenic coarse porous materials (CPMs) are mainly used in practice because of their high porosity. However, the knowledge of the hydraulic behavior of CPMs as well as of their mixtures with other substrates is limited, provoking their suboptimal usage. Therefore, we determined the water retention characteristics, including the available water capacity (AWC) of six geogenic CPMs: porlith, expanded shale, expanded clay, tuff, pumice, and lava. In order to obtain the water retention characteristics of the CPMs as well as of their mixture with sand (1:4 per volume), the following methods adapted from soil physics were applied over a wide range of pressure heads: Equi-pF apparatus, ceramic tension plates, pressure plate extractors, WP4C apparatus, and water vapor adsorption. The results were used to parametrize the modified Kosugi model (using SHYPFIT 2.0). Porlith and tuff have the highest AWC (0.37 m3 m−3 and 0.17 m3 m−3, respectively) and are the only ones which can be recommended as effective water-retaining materials. Further materials exhibit an AWC less than 0.10 m3 m−3. The CPMs exhibit a bimodal pore size distribution, which can be well described by the applied model, except for pumice and expanded shale. The mixtures present overall low AWCs up to 0.07 m3 m−3, with the pure sand having less than 0.03 m3 m−3. For practical application a quite high ratio of CPM is needed, and the mixing material must be adapted to the hydraulic properties of the CPMs. The water inside the CPMs may be easily available for plant roots able to penetrate in the CPMs’ coarse pores. [ABSTRACT FROM AUTHOR]