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Straw incorporation with nitrogen (N) fertilization is crucial for enhancing soil fertility and minimizing negative environmental impacts by altering the magnitude and direction of soil N transformation processes. However, the response of soil N transformations to long-term carbon (C) and N inputs, and their primary driving factors, remain poorly understood. Thus, a 15 N tracing study was conducted to investigate the effects of straw incorporation (AS) and straw removal (NS) with N levels of 0, 150 and 250 kg N ha -1 per season (N0, N150 and N250) on gross N transformation rates in the North China Plain after 6-year trial. Results indicated that at N0, AS significantly increased soil microbial immobilization of nitrate (NO 3 - -N, I NO3 ) and autotrophic nitrification rates (O NH4 ) compared to NS. With N fertilization, AS increased gross N immobilization (I total ), ammonium-N immobilization (NH 4 + -N, I NH4 ), net NH 4 + -N immobilization (I netNH4 ) and net NH 4 + -N absorption rates (A netNH4 ). Specifically, at N150, AS significantly increased recalcitrant organic N mineralization rate (M Nrec ), while significantly reducing O NH4 , labile organic N mineralization (M Nlab ), and gross N mineralization rates (M total ). At N250, A netNH4 , M Nlab , M Nrec and O NH4 under AS were significantly higher than under NS. Nitrogen application significantly increased O NH4 , I total and I NO3 under two straw management practices, and enhanced I NH4 and I netNH4 under AS. Compared to N250, N150 significantly increased I NH4 and I netNH4 under AS, while decreasing M total , all of which positively influenced the rates of assimilation, mineralization and clay mineral adsorption. Overall, this study provides new insights into reducing N fertilization under straw incorporation by quantifying soil N transformation processes.3 - -N and dissolved organic carbon (DOC) were master factors controlling immobilization, total nitrogen (TN), hydrolysable NH 4 + -N (HNN) and stable organic N significantly affected A netNH4 , while labile organic N were the key environmental factors affecting M Nrec , all of which positively influenced the rates of assimilation, mineralization and clay mineral adsorption. Overall, this study provides new insights into reducing N fertilization under straw incorporation by quantifying soil N transformation processes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Drained agricultural peat soils pollute both the atmosphere and watercourses. Biochar has been observed to decrease greenhouse gas (GHG) emissions and nutrient loading in mineral soils. We studied effects of three biochar types with two application rates (10 and 30 Mg ha -1 ) on GHG fluxes as well as N and P leaching on peat soil. Peat monoliths were drilled from a long-term cultivated field and were watered either slightly (five dry periods) or heavily (four rainfall periods) during an 11-month laboratory experiment with intact peat columns. The incubation of bare peat profiles enhanced peat decomposition leading to high CO 2 (up to 1300 mg CO 2  m -2  h -1 ) and N 2 O emissions (even 10,000-50,000 μg N 2 O m -2  h -1 ) and NO 3 - -N leaching (even 300-700 mg L -1 ) in all treatments. In the beginning of the experiment, the lower application rate of pine bark biochars increased N 2 O emission compared to control, but otherwise none of the biochars or their application rates significantly affected gas fluxes or nutrient leaching. These results indicate that moderate softwood biochar application does not help to mitigate the environmental problems of agricultural peat soils. Higher application rate of biochar pyrolyzed at high temperature is recommended for further studies with peat soils., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Climate change can pose a significant threat to terrestrial ecosystems by disrupting the circulation of soil nitrogen. However, experimental analyses on the effect of climate change on soil nitrogen cycles and the implications for the conservation of key wildlife species (i.e., the giant panda, Ailuropoda melanoleuca) remain understudied. We investigated the effects of a 1.5 °C, 3 °C, and 4.5 °C temperature increase on nitrogen distribution in different soil layers of bamboo forest via an in-situ experiment and assessed the implications for the growth and survival of arrow bamboo (Bashania faberi), a critical food resource for giant pandas. Our results showed that warming treatments generally increased soil N content, while effects differed between surface soil and subsurface soil and at different warming treatments. Particularly an increase of 1.5 °C raised the subsurface soil NO 3 -N content, as well as the content of N in bamboo leaves. We found a significant positive correlation between the subsurface soil NO 3 -N content and the N content of arrow bamboo. An increase of 3-4.5 °C raised the content of total N and NO 3 -N in the surface soil and led to a reduction in the total aboveground biomass and survival rate of arrow bamboo. Limited warming (e.g., the increase of 0-1.5 °C) may promote the soil N cycle, raise the N-acetylglucosaminidase (NAG) enzyme activity, increase NO 3 -N in subsurface soil, increase the N content of bamboo, and boost the biomass of bamboo - all of which could be beneficial to giant panda survival. However, higher warming (e.g., an increase of 3-4.5 °C) resulted in mass death of bamboo and a large reduction in aboveground biomass. Our findings provide a cautiously optimistic scenario for bamboo forest ecosystems under low levels of warming over a short period of time, but risks from higher levels of warming may be serious, especially considering the unpredictability of global climatic change., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Residues of herbicides with the extensive applications may impact the soil ecosystem and ultimately threaten agricultural sustainability. However, the effects of long-term herbicide residues on soil multifunctionality and the soil microbial community remain poorly understood. Here, we evaluated relationships between soil multifunctionality and soil microbial communities with residual herbicide concentrations by surveying and analyzing 62 black soil samples collected from an agricultural area in northeastern China. Total residual herbicide concentrations varied from 35 to 568 μg/kg in the soil samples. The response of soil multifunctionality to increasing residual herbicide concentrations exhibited an inverted U-shaped relationship with a peak at approximately 310 μg/kg, with net mineralized organic nitrogen (Nm) and total nitrogen (TN) exhibiting the same trend. Microbial community richness was significantly lower in soil samples with high residual herbicide concentrations (> 310 μg/kg, HG) compared to low residual herbicide concentrations (< 310 μg/kg, LG). In addition, the relative abundances of specific keystone microbial genera differed significantly between LG and HG: norank&#95;f&#95;Acetobacteraceae, norank&#95;f&#95;Caldilineaceae, Candidatus&#95;Alysiosphaera, and Gonytrichum. The relative abundances of these genera were also significantly correlated with soil multifunctionality. Structural equation models (SEMs) further showed that herbicide residues influenced soil multifunctionality by affecting these specific keystone genera. Our study demonstrates that long-term herbicide residues significantly impact the multifunctionality of agricultural black soil, where low concentrations stimulate while high concentrations inhibit, underscoring the need for reasonable application of herbicides to maintain soil ecosystem health., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Microplastics, as emerging contaminants, pose a serious threat to terrestrial ecosystems, yet their impact on plant communities remains largely unexplored. This study utilized the soil seed bank to establish naturally germinated plant communities and investigated the effects of polyethylene (PE) and polypropylene (PP) on community characteristics. Additionally, the study aimed to elucidate the mechanisms by which variations in soil properties influenced plant community. The results indicated that microplastics led to a significant increase in soil available potassium (AK), likely due to alterations in soil microorganism proliferation. Furthermore, microplastics caused a decrease in soil salinity, total phosphorus (TP), and ammonium nitrogen (AN). Additionally, plant community composition shifted, resulting in reduced stability and niche breadth of dominant species. Microplastics also impacted niche overlap and interspecific associations among dominant species, possibly due to the reduced accessibility of resources for dominant species. Salinity, AK, and TP were identified as major drivers of changes in niche breadth, niche overlap, and community stability, with TP exerting the strongest impact on plant community composition. These findings provide valuable insights for the restoration of plant communities in coastal saline-alkali wetland contaminated by microplastics., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The ecological function of biological crusts in arid and semi-arid areas is of great importance. Bacteria, as a crucial microbial group in biological crusts, play a key role in the formation, nutrient cycling, and regulation of these crusts. However, the succession of biological crusts and the diversity of bacterial communities, along with key environmental factors in the Loess Plateau's hilly and gully areas, remain unclear. This study investigated soil bacterial abundance and diversity in bare soil (BS), alga-lichen mixed crust (MC), and alga-lichen mixed crust subsoil (MCS) using high-throughput sequencing methods. It explored the relationship between the bacterial community in biological crusts and key environmental factors. The results indicated that the Chao1, Shannon index, and phylogenetic diversity of bacteria significantly increased with the succession of biological crusts. There were notable differences in the community composition and structure of bacteria at different stages of crust development, with Rubrobacteria and Cyanobacteriia dominating in MCS. Effective phosphorus, available potassium, nitrogen, pH, and total organic carbon were identified as key environmental factors affecting soil bacterial communities. In summary, the succession of biological crusts alters soil physicochemical characteristics and creates different ecological niches for bacterial communities. Soil nutrients and pH play a crucial role in the selection of bacterial species and the shaping of bacterial communities in the Loess Plateau's hilly and gully areas., (© 2024. The Author(s).)

Soil nutrient levels play a crucial role in determining crop yield. A comprehensive understanding of the spatial distribution patterns and evaluation grades of soil nutrients is of significant practical importance for informed fertilization practices, enhancing crop production, and optimizing agricultural land utilization. This study focuses on the urban area of Kashi Prefecture in Xinjiang as a case study. Utilizing soil sample data, GIS spatial interpolation analysis was conducted, incorporating plot boundary information to propose a comprehensive evaluation method for assessing soil nutrient levels at the plot level. Experimental findings revealed the following: (1) The average values of soil organic matter (SOM), total nitrogen (AN), total potassium (AK), and total phosphorus (AP) in the study area were determined to be 13.3 g/kg, 0.74 g/kg, 0.33 g/kg, and 0.03 g/kg, respectively. Among these, AN and SOM were classified as the fourth grade, indicating relatively deficient levels, while AK and AP were classified as the first and second grade, indicating relatively abundant levels. (2) The comprehensive evaluation of soil nutrient grades in the study area primarily fell within the third, fourth, and second grades, representing areas of 29.08 km2, 25 km2, and 4.05 km2, accounting for 50.03%, 43%, and 6.97% of the total area, respectively. (3) The evaluation results of soil nutrient levels at the plot level emphasized the boundary characteristics and provided a more refined assessment grade. This evaluation method is better suited to meet the practical production requirements of farmers and is considered feasible. The outcomes of this study can serve as a reference for precision agriculture management., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Xu, He. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

To investigate the characteristics of grassland degradation on a regional scale in Xizang, data on grassland degradation from the second grassland survey of Xizang and 12 vegetation and soil indicators from the National Tibetan Plateau Data Center were collected. Using ArcMap, 10 000 random sample points were selected on raster data （excluding non-grassland, desertification, and salinization data, leaving 7 949 valid sample points）. The multi-value extraction to-point method was applied to extract degradation and indicator data for each sample point. The characteristics of degraded grassland vegetation and soil and their relationships were analyzed in Xizang. Moreover, random forest modeling was conducted to predict the trend of grassland ecosystem changes. The results indicated that： ① The grasslands in Xizang were primarily composed of alpine steppe and alpine meadow types, accounting for 45.83% and 41.15% of the valid sample points, respectively. ② With the intensification of grassland degradation, the number of steppe-type species among the 17 grassland types gradually decreased, and the proportion of steppe dominated by species such as Stipa purpurea and Carex moorcroftii decreased, whereas the proportion of miscellaneous grasses and Dasiphora fruticosa increased. ③ As the degree of degradation increased, vegetation indicators generally showed a declining trend, with soil total nitrogen, total phosphorus, total potassium, and organic carbon decreasing, whereas soil pH and bulk density increased, and soil moisture content was not significant. ④ A positive correlation exists between soil moisture content, total nitrogen, total phosphorus, total potassium, organic carbon, vegetation cover, net primary productivity of vegetation, normalized difference vegetation index, aboveground biomass, and habitat quality. However, there was a negative correlation between pH and soil bulk density, and the correlation coefficients among various indicators decreased with the intensification of degradation. ⑤ The random forest simulation results showed that during the degradation process, the contribution rates of soil bulk density and habitat quality both exceeded 12%, with the model prediction accuracy reaching 78%. The study revealed that grassland degradation in Xizang was closely related to soil bulk density and habitat quality, indicating that higher soil bulk density or lower habitat quality may correspond to more severe grassland degradation. This provides a scientific basis for future grassland conservation and management.

Increasing densities of woody plants, known as woody plant encroachment, is a phenomenon affecting savannas and grasslands in many parts of the world. Yet, these ecosystems sustain a significant proportion of the human population through the provision of ecosystem services, such as forage for livestock and wildlife production. While low to medium altitude rangelands are encroached by many species of woody plants, high altitude rangelands in southern Africa show increasing densities of Leucosidea sericea, a woody shrub or small to medium-sized tree. Influences of this species on rangeland dynamics are unknown. This study aimed to determine the influence of L. sericea on rangeland functioning in the Vuvu communal area in the Eastern Cape, South Africa. Effects of L. sericea on plant species diversity and composition, rangeland condition and grazing capacity were measured in sites of variable densities of the species in topographical locations designated as plains, upland and stream sites, using a point-to-tuft method along 50-m long transects. Soil samples were collected to a depth of 5 cm from plains, streams, and upland sites, and analysed for organic carbon, nitrogen, phosphorus, magnesium, calcium, and pH. Plant species richness and abundance were similar among topographical locations, which was reflected by the similar Shannon-Weiner (H') diversity indices among sites. Topographical locations differed significantly in species composition. The plains sites had a higher grazing capacity than stream sites, which had a grazing capacity similar to that of upland sites. Values of soil physicochemical properties were similar among the sites. Overall, soils were acidic (range in pH: 4.4-4.6) and had low amounts of organic carbon and total nitrogen. These findings suggest that L. sericea is not the primary cause of rangeland degradation as all sites were in poor condition as shown by the low grazing capacity, poor rangeland condition and depauperate species richness and diversity. Therefore, rangeland management should shift towards restoration strategies aimed to revitalise the rangeland., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Ndamane et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: The expansion of bamboo forests increases environmental heterogeneity in tea plantation ecosystems, affecting soil properties and microbial communities. Understanding these impacts is essential for developing sustainable bamboo management and maintaining ecological balance in tea plantations., Methods: We studied the effect of the continuous expansion of Pleioblastus amarus into tea plantations, by establishing five plot types: pure P. amarus forest area (BF), P. amarus forest interface area (BA), mixed forest interface area (MA), mixed forest center area (TB), and pure tea plantation area (TF). We conducted a comprehensive analysis of soil chemical properties and utilized Illumina sequencing to profile microbial community composition and diversity, emphasizing their responses to bamboo expansion., Results: (1) Bamboo expansion significantly raised soil pH and enhanced levels of organic matter, nitrogen, and phosphorus, particularly noticeable in BA and MA sites. In the TB sites, improvements in soil nutrients were statistically indistinguishable from those in pure tea plantation areas. (2) Continuous bamboo expansion led to significant changes in soil bacterial diversity, especially noticeable between BA and TF sites, while fungal diversity was unaffected. (3) Bamboo expansion substantially altered the composition of less abundant bacterial and fungal communities, which proved more sensitive to changes in soil chemical properties., Conclusion: The expansion of bamboo forests causes significant alterations in soil pH and nutrient characteristics, impacting the diversity and composition of soil bacteria in tea plantations. However, as expansion progresses, its long-term beneficial impact on soil quality in tea plantations appears limited., (© 2024. The Author(s).)

Priming effects of soil organic matter decomposition are critical to determine carbon budget and turnover in soil. Yet, the overall direction and intensity of soil priming remains under debate. A second-order meta-analysis was performed with 9296-paired observations from 363 primary studies to determine the intensity and general direction of priming effects depending on the compound type, nutrient availability, and ecosystem type. We found that fresh carbon inputs induced positive priming effects (+37%) in 97% of paired observations. Labile compounds induced larger priming effects (+73%) than complex organic compounds (+33%). Nutrients (e.g., N, P) added with organic compounds reduced the intensity of priming effects compared to compounds without N and P, reflecting "nutrient mining from soil organic matter" as one of the main mechanisms of priming effects. Notably, tundra, lakebeds, wetlands, and volcanic soils showed much larger priming effects (+125%) compared to soils under forests, croplands, and grasslands (+24…+32%). Our findings highlight that positive priming effects are predominant in most soils at a global scale. Optimizing strategies to incorporate fresh organic matter and nutrients is urgently needed to offset the priming-induced accelerated organic carbon turnover and possible losses., (© 2024 John Wiley & Sons Ltd.)

Acid rain and invasive plants have quintessential adverse impacts on terrestrial ecosystems. As an environmentally safe method for disposal of invasive plants, we tested the effect of biochar produced from these plants in altering soil deterioration under acid rain as compared with lime. Given the impacts of the feedstock type and soil properties on the response of soil to the added biochar, we hypothesized that the microbial community and functions would respond differently to the charred invasive plants under acid rain. A pot experiment was conducted to examine the response of soil microbiomes and functions to the biochar produced from Blackjack (Biden Pilosa), Wedelia (Wedelia trilobata), and Bitter vine (Mikania micrantha Kunth), or quicklime (CaO) at a rate of 1 % (w/w) under acid rain. Like soil pH, the nutrient contents (nitrogen, phosphorus, and potassium), calcium, and cation exchange capacity (CEC) were important as dominant edaphic factors affecting soil microbial community and functionality. In this respect, lime decreased nutrients availability, driven by 11-fold, 44 %, and 2-fold increments in calcium content, pH, and C/N ratio. Meanwhile, biochar improved nutrients availability under acid rain owing to maintaining a neutral pH (∼6.5), increasing calcium (by only 2-fold), and improving CEC, water repellency, and aggregation while decreasing the C/N ratio and aluminum content. Unlike biochar, lime decreased the relative abundance of Nitrosomonadaceae (the dominant ammonia-oxidizing bacteria) while augmenting the relative abundance of some fungal pathogens such as Spizellomycetaceae and Sporormiaceae. Given the highest nitrogen and dissolved organic carbon content than other biochar types, Wedelia-biochar resulted in the greatest relative abundance of Nitrosomonadaceae; thus, the microbial carbon and nitrogen biomasses were maximized. This study outlined the responses of the soil biogeochemical properties and the related microbial community structure and functionality to the biochar produced from invasive plants under acid rain. This study suggests that biochar can replace lime to ameliorate the effects of acid rain on soil physical, chemical and biological properties., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Microplastics (MPs), recognized as emerging pollutants, pose a significant threat to diverse organisms and have adverse effects on agricultural soil. High-density polyethylene (HDPE) holds a prominent position among prevalent forms of MPs. In the current investigations, the impact of HDPE was assessed at four different concentrations (0.25%, 0.5%, 0.75%, and 1.0%) on agricultural soil, microbial population, exoenzymes activities including amylase, cellulase, and invertase, and alteration in carbon-to-nitrogen (C/N) ratio. Both bacterial and fungal populations exhibited a non-concentration-dependent response to different concentrations of HDPE over time. In this study, we refer to the concentrations of 0.25%, 0.5%, 0.75%, and 1.0% as HT1, HT2, HT3, and HT4, respectively. Initial MP application significantly reduced bacterial colony counts for HT1, HT2, and HT4, while HT3 showed no significant change. On the 60th day, HT1 and HT3 exhibited a higher bacterial colony count compared to the control. On the other hand, fungal populations increased to maximum on day 1 but displayed no distinct time-dependent trend from days 15 to 60. Furthermore, enzyme activities decreased with increasing concentrations of MPs over an extended period. Molecular docking studies suggest that HDPE can hinder enzyme activity by forming hydrogen bonds with enzymes. The C/N ratio was found to be significantly higher in MP-treated soils on the 60th day relative to control, suggesting relatively slower degradation of carbon compounds in the MP-treated soils., (© 2024 The Author(s). Journal of Environmental Quality © 2024 American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.)

We assessed, in a field experiment, the effects of arbuscular mycorrhizal fungi (Rhizophagus intraradices) and plant growth-promoting bacteria (Azospirillum brasilense) on the soil biological activity and the growth of key pioneer species used in the revegetation of coal-mining areas undergoing recovery. We applied four inoculation treatments to the pioneer plant species (Lablab purpureus, Paspalum notatum, Crotalaria juncea, Neonotonia wightii, Stylosanthes guianensis, Andropogon gayanus and Trifolium repens) used in the recovery process: NI (Control - Non-inoculated), AZO (A. brasilense), AMF (R. intraradices), and co-inoculation of AZO and AMF. On the 75th and 180th days, we measured plant dry mass, mycorrhizal colonization, N and P concentration, and accumulation in plant tissue. We collected soil to quantify glomalin content and soil enzyme activity. After 180 days, we did a phytosociological characterization of the remaining spontaneous plants.The both microorganisms, singly or co-inoculated, promoted increases in different fractions of soil glomalin, acid phosphatase activity, and fluorescein diacetate activity at 75 and 180 days. The inoculation was linked to higher plant biomass production (62-89%) and increased plant P and N accumulation by 34-75% and 70-85% at 180 days, compared with the non-inoculated treatment. Among the pioneer species sown Crotalaria juncea produced the highest biomass at the 75th and 180th days (67% and 76% of all biomass), followed by Lablab purpureus (3% and 0.5%), while the other species failed to establish. At 180 days, we observed twenty spontaneous plant species growing in the area, primarily from the Poaceae family (74%). That suggests that the pioneer species present in the area do not hinder the ecological succession process. Inoculation of R. intraradices and A. brasilense, isolated or combined, increases soil biological activity, growth, and nutrient accumulation in key pioneer plant species, indicating the potential of that technique for the recovery of lands degraded by coal mining., (© 2024. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)

To understand how nutrient cycling and sequestration are influenced by different grazing periods, the C:N:P stoichiometry features of the plant-soil interface in the desert steppe were measured and evaluated. The 5-year seasonal grazing experiment employed four grazing period treatments: traditional time of grazing (TG), early termination of grazing (EG), delayed start of grazing (DG), and delayed start and early termination of grazing (DEG). Additionally, fenced off desert steppe served as the control. The grazing periods each had a differing impact on the C:N:P stoichiometry in both plant functional group and soil depth comparisons. Compared to the EG, DG, and DEG treatments, the TG treatment had a more significant impact on the C, N, and P pools of grass, as well as the C:P and N:P ratios of forbs, but had a reduced effect on the C:P and N:P ratios of legumes. In contrast to plants, the DG treatment exhibited greater advantages in increasing C pools within the 0-40 cm soil layer. Furthermore, in the 10-20 cm soil layer, the C:P and N:P ratios under the EG treatment were significantly higher, ranging from 8.88% to 53.41% and 72.34%-121.79%, respectively, compared to the other treatments (TG, DG, and DGE). The primary drivers of the C, N, and P pools during different grazing periods were above-ground biomass (AGB) and litter biomass (LB). Both lowering the plant C:P and N:P ratios and considerably raising the plant P pool during different grazing periods greatly weakened the P limitation of the desert steppe environment. It is predicted that delayed start grazing might be a management strategy for long-term ecosystem sustainability, as it regulates above-ground nutrient allocation and has a positive effect on soil C and N pools., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Zhuo liu reports financial support was provided by Ningxia University. Zhuo Liu reports financial support was provided by Ningxia University. This research was supported by the National Natural Science Foundation of China (No.32060406), the Nation Guide Local Science and Technology Development Projects of Ningxia Province (No.2023FRD05035), the Ningxia Key Research and Development Program (No.2020BBF02003), the Ningxia Science and Technology Innovation Leader Training Project (No.KJT2018003), and the First-class Discipline Construction Project (Grassland Science Discipline) for the high school in Ningxia (No. NXYLXK 2017A01), (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Grazing plays a key role in ecosystem biogeochemistry, particularly soil carbon (C) pools. The non-trophic interactions between herbivores and soil processes through herbivore trampling have recently attracted extensive attention. However, their concurrent and legacy effects on the ecosystem properties and processes are still not clear, due to their effects being hard to separate via field experiments. In this study, we conducted a 2-year simulated-sheep-trampling experiment with four trampling intensity treatments (i.e., T0, T40, T80, and T120 for 0, 40, 80, and 120 hoofprints m -2 , respectively) in a typical steppe to explore the concurrent and legacy effects of trampling on grassland ecosystem properties and processing. In 2017 (trampling treatment year), we found that trampling decreased aboveground biomass (AGB) of plant community and community-weighted mean shoot C concentration (CWM C), soil available nitrogen (N) and available phosphorus (P), but did not affect plant species diversity and belowground biomass (BGB). We show that compared with T0, trampling increased soil bulk density (BD) at T80, and decreased soil organic carbon (SOC) stocks. After the cessation of trampling for two years (i.e., in 2019), previous trampling increased plant diversity and BGB, reaching the highest values at T80, but decreased soil available N and available P. Compared with T0, previous trampling significantly increased soil BD at T120, while significantly decreased CWM C at T80 and T120, and reduced SOC stocks at T80. Compared with 2017, the trampling negative legacy effects amplified at T80 but weakened at T40 and T120. We also show that trampling-induced decreases in soil available N, AGB of Fabaceae and CWM C were the main predictors of decreasing SOC stocks in 2017, while previous trampling-induced legacy effects on soil available P, AGB of Poaceae and CWM C contributed to the variations of SOC stocks in 2019. Taken together, short-term trampling with low intensity could maintain most plant functions, while previous trampling with low intensity was beneficial to most plant and soil functions. The results of this study show that T40 caused by sheep managed at a stocking rate of 2.7 sheep ha -1 is most suitable for grassland adaptive management in the typical steppe. The ecosystem functions can be maintained under a high stocking rate through the process of providing enough time to rebuild sufficient vegetation cover and restore soil through measures such as regional rotational grazing and seasonal grazing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Ecological stoichiometry serves as a valuable tool for comprehending biogeochemical cycles within grassland ecosystems. The impact of grazing time on the concentration and stoichiometric characteristics of carbon (C), nitrogen (N), and phosphorus (P) in desert steppe ecosystems remains ambiguous. This research was carried out in a desert grassland utilizing a completely randomized experimental design. Four distinct grazing time treatments were implemented: fenced grassland (FG, control), delay to start and early to end grazing grassland (DEG), delay to start grazing grassland (DG), and traditional grazing grassland (TG). The patterns of C, N, and P concentrations and their stoichiometry in various components of the ecosystem, as well as their driving factors under different grazing times were examined. The results showed that grazing time positively influenced C and N concentrations in leaves, while negatively affecting N concentrations in roots. TG had a significant positive effect on soil P concentrations but a negative effect on soil C:P and N:P ratios. Plant C:N, C:P, and N: P ratios were mainly influenced by N and P. The soil C:N ratio was primarily influenced by soil N, the soil C:P ratio was affected by both soil C and P, and the soil N:P ratio was influenced by both soil N and P. The growth of plants in desert steppes is mainly limited by P; however, as grazing time increased, P limitation gradually decreased and the N cycling rate increased. C-N, C-P, and N-P in various plant organs and soils demonstrated significant anisotropic growth relationships at different grazing times. Soil organic carbon, pH, and soil total phosphorus were the main driving factors that affected changes in ecological C:N:P stoichiometry. These results will help improve grassland management and anticipate the response of grassland systems to external disturbances with greater accuracy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Applying biochar to nitrogen (N)-fertilized soils is recognized as an effective technique for enhancing soil carbon (C) accumulation and improving agroecosystem sustainability. However, the impact of co-application of biochar and N fertilizer on soil C and N stocks, as well as their fractions, within the 0-60 cm soil profile remains unclear. This study examined the soil C and N fractions as well as stocks in soil profiles, and the primary influencing factors in wheat field with different rates of biochar (0, 20 and 40 t ha -1 ; B0, B1 and B2) and N application (0, 180 and 360 kg N ha -1 ; N0, N1 and N2). The results revealed that compared to B0N0 treatment, biochar plus N application increased soil organic carbon (SOC) and dissolved organic carbon (DOC), while N application alone decreased microbial biomass carbon (MBC). SOC in topsoil (0-10 cm) and DOC in subsoil (40-60 cm) were more susceptible to biochar and N application. The combined application of biochar and N enhanced soil N fractions, with NO 3 -N having the highest sensitivity than the other N fractions, whereas biochar application alone decreased topsoil inorganic N content. Biochar and N application significantly altered soil C stocks (4.33%-42.20%) and N stocks (-1.24%-20.91%) within the 0-60 cm soil layers, and belowground biomass and SOC were the main influencing factors, respectively. The combination of moderate biochar (42.35 t ha - -N having the highest sensitivity than the other N fractions, whereas biochar application alone decreased topsoil inorganic N content. Biochar and N application significantly altered soil C stocks (4.33%-42.20%) and N stocks (-1.24%-20.91%) within the 0-60 cm soil layers, and belowground biomass and SOC were the main influencing factors, respectively. The combination of moderate biochar (42.35 t ha -1 ) application was the most beneficial for soil C accumulation in the 0-60 cm depth. These findings indicate the positive impacts of co-applying of biochar and N in agroecosystems on soil C and N accumulations, and highlight the importance of C and N stabilization in both topsoil and subsoil under management practice.-1 ) application was the most beneficial for soil C accumulation in the 0-60 cm depth. These findings indicate the positive impacts of co-applying of biochar and N in agroecosystems on soil C and N accumulations, and highlight the importance of C and N stabilization in both topsoil and subsoil under management practice., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The application of organic fertilisers and biochar has become widespread in agroforestry ecosystems to enhance the yield and quality of crops and medicinal plants. However, their specific impact on both the yield and quality of Paris polyphylla (P. polyphylla), along with the underlying mechanisms, remains unclear. In this study, we investigated the distinct effects of organic fertiliser (at concentrations of 5% and 10%) and biochar application (at levels of 2% and 4%) on P. polyphylla saponin content. This content is intricately regulated by available soil nutrients, enzyme activities, and microbial community compositions and activities. Our results clearly demonstrated a significant increase in the saponin content, including total saponin, polyphyllin I (PPI), polyphyllin II (PPII), polyphyllin VI (PPVI), and polyphyllin VII (PPVII), in P. polyphylla following the application of both biochar and organic fertiliser. Moreover, in comparison to the control group, the addition of biochar and organic fertiliser led to a considerable rise in the activity of glycosyltransferase enzyme (GTS) and cycloartenol synthase (CAS) in P. polyphylla. Additionally, it increased soil available potassium (AK) and soil organic matter (SOM) concentration, along with the activity of urease, acid phosphatase, and catalase, although biochar amendment resulted in a decrease in nitrate nitrogen (NO 3 -N) concentration. Crucially, our findings revealed a positive correlation between total saponin content and the activity of CAS in P. polyphylla, soil AK, SOM concentration, and the activities of urease, acid phosphatase, and catalase. Conversely, there was a negative correlation with NO - -N content. Furthermore, the application of organic fertiliser and biochar significantly influenced microbial community structures and specific microbial taxa. Notably, total saponin content exhibited a positive relationship with the relative abundances of Dehalococcoidia, Saccharomycetes, and Agaricomycetes taxa while showing a negative correlation with the abundance of Verrucomicrobiae. In conclusion, the observed increase in saponin content can be attributed to the modulation of specific microbial taxa in soils, as well as alterations in soil nutrients and enzyme activities resulting from the application of biochar and organic fertiliser. This study identifies a potential mechanism for enhancing saponin content in the artificial cultivation of P. polyphylla.3 - -N content. Furthermore, the application of organic fertiliser and biochar significantly influenced microbial community structures and specific microbial taxa. Notably, total saponin content exhibited a positive relationship with the relative abundances of Dehalococcoidia, Saccharomycetes, and Agaricomycetes taxa while showing a negative correlation with the abundance of Verrucomicrobiae. In conclusion, the observed increase in saponin content can be attributed to the modulation of specific microbial taxa in soils, as well as alterations in soil nutrients and enzyme activities resulting from the application of biochar and organic fertiliser. This study identifies a potential mechanism for enhancing saponin content in the artificial cultivation of P. polyphylla., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The Organisation for Economic Co-operation and Development (OECD) 216 test guideline investigates the impact of agrochemicals on soil nitrogen transformation. After an evaluation of 465 OECD 216 studies, we describe two distinct yet contrasting outcomes in control nontreated samples that are possible in this testing framework, which we term the "rise" (consistent increases in nitrate concentrations throughout the test period) and "dip" (initial decline in nitrate concentration between Days 0-7, followed by a net-generation of nitrate across Days 7-28) responses. We raise significant concerns that control data from standardized, internationally recognized test guidelines can demonstrate such dissimilar patterns. We propose that, when present, the dip response undermines the intended functioning of the test system and removes the ability to draw appropriate ecotoxicological inferences from the data. In this work, we hypothesize the dip response is a product of conducting the study in low nitrogen content soils. Our results indicate that the dip response can be alleviated by using ammonium sulfate as an immediately available inorganic nitrogen source in place of the guideline-mandated complex, organic lucerne meal, demonstrating the influence of nitrogen availability and accessibility. However, not all low nitrogen soils exhibited the dip response, indicating the involvement of additional unidentified factors. Using our data and real-world regulatory examples, we advocate that datasets displaying the dip response should not be considered valid OECD 216 studies due to the influence of soil properties precluding an assessment of whether any impacts observed are driven solely by the test compound in question or are instead a product of the soil used. We propose methods to account for these soil-specific responses that could be integrated into the conduct and interpretation of OECD 216 studies. Such amendments will improve the reliability and robustness of the study system and enhance confidence in ecotoxicological conclusions derived from OECD 216 datasets. Integr Environ Assess Manag 2024;20:1611-1624. © 2024 SETAC., (© 2024 SETAC.)

Soil organic carbon and nitrogen play pivotal roles as indicators of soil quality and ecological functioning in wetlands. The escalating impact of human activities and climate change has led to a severe degradation of wetland soils, particularly in semi-arid regions. However, an understanding of the factors governing the dynamics of total soil organic carbon (TSOC) and total soil nitrogen (TSN) in semi-arid areas remains elusive, impeding a comprehensive understanding of wetland ecological functions. The present study investigated variations in TSOC and TSN content as well as vegetation and soil physicochemical properties under five different land management practices (mowed wetlands, mowed and slightly grazed wetlands, moderately grazed wetlands, heavily grazed wetlands, and natural wetlands unaffected by human interference) in the semi-arid Songnen Plain region of China. The results revealed significant decreases in TSOC and TSN content within managed wetlands compared to natural wetlands. Moreover, positive correlations were observed between pairs of SOC-TN or their storage values for SOC (TSOC)-TN (TSN). Furthermore, TSOC and TSN exhibited significant positive associations with aboveground and belowground biomass levels, stem C:N, stem C:P, soil C:P, and soil N:P. Additionally, redundancy analysis indicated that species diversity accounted for 37.4% of the variations in TSOC-TSN while belowground biomass accounted for 8.5% of the variations. Furthermore, nutrient content within stems (particularly N content and C:P) contributed to a 37.2% variation in TSOC and TSN whereas root nutrient content (especially N:P, C:N, and C:P) contributed to a 15.3% variation. Soil C:P, C:N, and total phosphorous (TP) content accounted for 65.7%, 9.6%, and 7.5% of variations of TSOC and TSN, respectively. Besides, variation partitioning analysis revealed that plant community characteristics, community nutrient content, and soil physicochemical properties collectively influenced the dynamics of TSOC and TSN. Among these factors, soil physicochemical properties emerged as the primary drivers of carbon and nitrogen dynamics in degraded wetlands in semi-arid regions. The impact on TSN was more pronounced than that of TSOC. This study provides valuable insights for understanding the processes and mechanisms underlying carbon and nitrogen accumulation in degraded wetlands, facilitating the development of regionally adaptive management plans under different management practices., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Land degradation often results in poor soil quality in many parts of Ethiopia, including the study area. To address this issue and promote sustainable land management practices, various land use and management methods (LUMMs) have been implemented. However, little information is available regarding how these management practices influence overall soil quality dynamics of the study area. This study aimed at evaluating soil quality dynamics in the Urago micro-watershed, central highlands of Ethiopia, under major LUMMs: barren land (BL), grassland (GL), established farm boundary (EFB), restored degraded land (RDL), and stone-supported soil bund (SSB). Forty-five disturbed and fifteen undisturbed soil samples were collected from the ploughed soil layer (0-20 cm) of each LUMM and analysed for selected physicochemical properties to be used as indicators of soil quality. Principal component analysis and multiple correlation were used to select the minimum data set (MDS) to evaluate the overall soil quality index (SQI). The MDS included SOC, clay content, exchangeable Mg 2+ , and available P, which could replace other indicators for assessing the overall soil quality dynamics of the study watershed. The result showed notable variations in particle-size fractions, soil organic carbon (SOC), total nitrogen (TN), available P (av. P), and exchangeable Na + , K + , and Mg 2+ levels among the LUMMs. RDL had higher sand and silt contents than SSB, whereas SSB had higher clay content compared to RDL, GL, and BL. GL, RDL, and EFB showed significantly higher levels of SOC, TN, and av. P, respectively, compared to other LUMMs. The obtained SQI showed that GL had the highest score (0.847), followed by SSB (0.703), RDL (0.701), EFB (0.644), and BL (0.628). This underscores the significance of stone-supported soil bund and restored degraded land as an efficient management method to enhance soil quality and agro-ecosystem through conserving soil and encouraging sustainable farming practices., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The Qinghai-Tibet Plateau is particularly vulnerable to the effects of climate change and disturbances caused by human activity. To better understand the interactions between soil nitrogen and sulfur cycles and human activities on the plateau, the distribution characteristics of soil nitrogen and sulfur density and their influencing factors for three soil layers in Machin County at depths of 0-20 cm, 0-100 cm, and 0-180 cm are discussed in this paper. The results indicated that at depths of 0-180 cm, soil nitrogen density in Machin County varied between 1.36 and 16.85 kg/m 2 , while sulfur density ranged from 0.37 to 4.61 kg/m 2 . The effects of three factors-geological background, land use status, and soil type-on soil nitrogen and sulfur density were all highly significant (p < 0.01). Specifically, natural factors such as soil type and geological background, along with anthropogenic factors including land use practices and grazing intensity, were identified as decisive in causing spatial variations in soil nitrogen and sulfur density. Machin County on the Tibetan Plateau exhibits natural nitrogen and sulfur sinks; However, it is crucial to monitor the emissions of N 2 O and SO 2 into the atmosphere from areas with high external nitrogen and sulfur inputs and low fertility retention capacities, such as bare land. On this basis, changes in the spatial and temporal scales of the nitrogen and sulfur cycles in soils and their source-sink relationships remain the focus of future research., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Different vegetation restoration methods have improved soil quality to varying degrees. This study, focused on the forest-grassland-desert transition zone in the Hebei-Inner Mongolia border region, and employed a systematic grid sampling method to establish fixed monitoring plots in the Saihanba Mechanized Forest Farm and the Ulan Buh Grassland. The differences in soil quality evolution across various vegetation restoration methods under the same climatic and soil historical conditions were analyzed, elucidating the roles of these vegetation restoration methods in degraded forest ecosystems, with the aim of providing a reference for ecological restoration under similar land conditions. This study used a grid method to establish sample points in the forest-grassland-desert transitional zone and assessed five methods of vegetation restoration sites: artificial forest composed of native species of Larix principis-rupprechtii (FL), artificial forest composed of exotic Pinus sylvestris var. mongolica (FP), natural secondary broad-leaved forest (FN), open grassland (GO), and enclosed grassland (GC). The differences in soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkaline hydrolysis nitrogen (AN), rapidly available phosphorus (AP) and rapidly available potassium (AK) among the different vegetation restoration sites were compared via variance analysis, and the soil quality index (SQI) was calculated to assess the soil quality at the sample points. The SOC, TN, and AN contents of forest soil were significantly greater than those of grassland, and the TN, TP, AN, AK, and SOC contents of FL, FN, and GC were significantly greater than those of FP and GO. Among them, the TN, TP, and SOC contents were the highest in the FL, reaching 2.74, 0.39, and 47.27 g kg -1 , respectively. In terms of ecological stoichiometric characteristics, the average N:P ratio in the study area was 6.68, indicating a serious lack of N in the study area. Among the different types of restoration sites, the effect was stronger in the FP than in the FL, and the TN and AN contents were only 1.48 g kg -1 and 116.69 mg kg -1 , respectively. The SQI in the FL was not significantly different from that in the FN or GC, but it was significantly greater than that in the FP and GO. These findings indicate that native tree species restoration in degraded forest ecosystems significantly improved soil quality, while the introduction of exotic tree species for afforestation had a minimal effect on improving soil quality., (© 2024. The Author(s).)

Striking the right nutrient balance is essential for sustainable farming and ecosystem health. In this regard, field experiments were conducted in three phases viz., fertility gradient experiment, main experiment and validation experiment through a soil test crop response approach to develop and validate fertilizer prescription equations for sweet corn in comparison with general recommended dose and soil fertility rating approach. The soil data, fresh cob yield, and NPK uptake were used for establishing four important basic parameters, viz., nutrient requirement (kg t-1), contribution of nutrients from fertilizers, soil, and organic manure. The results revealed that nutrients required to produce one tonne of fresh cob yield (NR) were 5.85 kg, 0.87 kg and 4.31kg for N, P and K, respectively under the STCR NPK alone approach and 6.07 kg, 0.92 kg and 4.33 kg for N, P and K, respectively under STCR NPK+FYM approach. In the validation experiment, STCR NPK+FYM approach for the targeted yield of 25 t ha-1 recorded higher fresh cob yield (23.38 t ha-1) and dry stover yield (35.07 t ha-1) which were significantly higher compared to general recommended dose and soil fertility rating approach. The developed STCR equations for the aforesaid crop are valid as the percent deviation of cob yield from the targeted yield was within ±10%. Similarly, highest nutrient use efficiency was achieved with the STCR approach, specifically when targeting a lower yield through an NPK+FYM mode. Thus, implementation of the STCR approach of fertilizer prescription, with or without FYM, at targeted yields of 25 and 22 t ha-1, not only surpassed the effects of the other fertilizer recommendation approach in terms of cob yields, but also increased NPK uptake, improved nutrient use efficiency and greater economic returns., Competing Interests: The author reported no potential conflict of interest., (Copyright: © 2024 Rangaiah et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Soil organic carbon (SOC) is known to vary among different ecosystems and soilscapes, yet the degree of variation remains uncertain. Comparing SOC levels in undisturbed ecosystems like forests with those in gradually altered ecosystems can provide valuable insights into the impact of land use on carbon dynamics. This study aimed to evaluate the effects of different land uses on soil fertility parameters in the tropical region of Kerala, focusing on forests as well as cultivated agricultural landscape such as coconut, pepper, tapioca, acacia plantations, and mixed home garden cropping systems. Significant variations were observed among different crops and land use systems in terms of soil fertility. Forests exhibited the highest SOC content at 3.78 g kg-1, while acacia plantations showed the lowest at 0.76 g kg-1. Additionally, various soil properties such as different carbon fractions (e.g., humic acid, fulvic acid), total nitrogen, carbon, available nutrients, physical properties, aggregate size fractions, microbial biomass carbon, and spectral signatures differed significantly across the different land uses. These findings suggest a decline in soil fertility in altered ecosystems compared to adjacent forest soils, highlighting the vital role of forests in conserving natural resources and maintaining soil health. In addition, among the different landscapes studied, mixed cropping systems of home gardens sustained soil fertility better than monocropping systems. The observed variations in soil physicochemical properties among different land use types indicate a threat to sustainable crop production. Effective management practices aimed at improving soil fertility and sustaining crop production in these altered ecosystems are essential. This study highlights the importance of adopting appropriate management strategies to conserve soil health and ensure sustainable crop production in tropical landscapes like Kerala. The holistic approach adopted in this study, encompassing a wide range of soil fertility parameters across various land uses, along with its implications for sustainable land management, adds significant novelty and relevance to the existing literature on soil dynamics in tropical regions like Kerala., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Reservoir is easy to be polluted by nutrients and heavy metals in the surrounding soil. There is a close relationship between heavy metals and nutrients in soil. Nutrient salts will affect the activity of heavy metals, and heavy metal pollution will affect plant growth and nutrient salt absorption, thus affecting ecosystem health. This study was performed to evaluate nutrients (TN, TP) and heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) in the upper watershed of Xiashan Reservoir by the enrichment factor, the geoaccumulation index, the enrichment factor and leaching experiments. The results showed that the average enrichment of TN and TP reached the level of moderate pollution. The nutrient enrichment of different sampling sites increased gradually from south to north, which may be affected by the topography of the study area. The comprehensive trophic level exceeds the criteria for a state of severe eutrophication of water bodies, which may lead to the enrichment of nitrogen and phosphorus in the water body through processes such as runoff. Evaluation of the geoaccumulation index and potential ecological risk index revealed that the soil was primarily contaminated by Cd and Hg, which are in the level of considerable potential ecological risk and high potential ecological risk. So most attention should be paid to Cd and Hg pollution. Pollution control of heavy metals in soil is a priority because they are more difficult to leach than nutrients. This study provided an insight into the nitrogen and phosphorus control and heavy metal pollution management in the upper watershed of Xiashan Reservoir., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The coverage of accumulated snow plays a significant role in inducing changes in both microbial activity and environmental factors within freeze-thaw soil systems. This study aimed to analyze the impact of snow cover on the dynamics of archeal communities in freeze-thaw soil. Furthermore, it seeks to investigate the role of fertilization in freeze-thaw soil. Four treatments were established based on snow cover and fertilization:No snow and no fertilizer (CK-N), snow cover without fertilizer (X-N), fertilizer without snow cover (T-N), and both fertilizer and snow cover (T-X). The research findings indicated that after snow cover treatment, the carbon, nitrogen, and phosphorus content in freeze-thaw soil exhibit periodic fluctuations. Snow covered effectively altered the community composition of bacteria and archaea in the soil, with a greater impact on archaeal communities than on bacterial communities. Snow covered improves the stability of archaeal communities in freeze-thaw soil. Additionally, the arrival of snow also enhanced the correlation between archaea and environmental factors, with the key archaeal phyla involved being Nanoarchaeota and Crenarchaeota. Further research showed that the application of organic fertilizers also had some impact on freeze-thaw soil, but this impact was smaller compared to snow cover. In summary, the arrival of snow could alter the archaeal community and protect nutrient elements in freeze-thaw soil, reducing their loss, and its effect is more pronounced compared to the application of organic fertilizers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Pitaya (Hylocereus undulatus) is a significant cash crop in the karst region of Southwest China. Ecological stoichiometry is an essential method to research biogeochemical cycles and limiting elements. The purpose of this study was to explore the stoichiometric characteristics of C, N, and P in Karst pitaya orchards and fruit quality and to elucidate the mechanism and process of nutrient cycling. The results showed that: (1) Fruit quality was highest under the combination of chemical and organic fertilizers. Compared to the control, the contents of per-fruit weight, vitamin C, and soluble sugar increased significantly by 55.5%, 60.7%, and 23.0%, respectively, while the content of titratable acidity decreased significantly by 22.0%. (2) The content of soil nutrients under fertilization stress showed a downward trend in general, as did microbial biomass and extracellular enzyme activities. (3) Different fertilization treatments significantly affected the soil-microbial stoichiometry C:N ratio, C:P ratio, with research areas being significantly limited by C and P. (4) Spearman and PLS-SEM (partial least squares-structural equation model) analysis results showed that under the influence of fertilization, there was a significant positive effect between microorganisms and soil nutrients, but a significant negative effect between soil nutrients and quality. The results of this study offer an innovative perspective on pitaya quality research in Karst areas., (© 2024. The Author(s).)

Soil microorganisms are the most active participants in terrestrial ecosystems, and have key roles in biogeochemical cycles and ecosystem functions. Despite the extensive research on soil pH as a key predictor of microbial community and composition, a limitation of these studies lies in determining whether bacterial and/or fungal communities are directly or indirectly influenced by pH. We conducted a controlled laboratory experiment to investigate the effects of soil pH amendment (+/- 1-2 units) with six levels on soil microbial communities in two contrasting Chinese agricultural soils (pH 8.43 in Dezhou, located in the North China Plain, Shandong vs pH 6.17 in Wuxi, located in the Taihu Lake region, Jiangsu, east China). Results showed that the fungal diversity and composition were related to soil pH, but the effects were much lower than the effects of soil pH on bacterial community in two soils. The diversity and composition of bacterial communities were more closely associated with soil pH in Wuxi soils compared to Dezhou soils. The alpha diversity of bacterial communities peaked near in situ pH levels in both soils, displaying a quadratic fitting pattern. Redundancy analysis and variation partition analysis indicated that soil pH affected bacterial community and composition by directly imposing a physiological constraint on soil bacteria and indirectly altering soil characteristics (e.g., nutrient availability). The study also examined complete curves of taxa relative abundances at the phylum and family levels in response to soil pH, with most relationships conforming to a quadratic fitting pattern, indicating soil pH is a reliable predictor. Furthermore, soil pH amendment affected the transformation of nitrogen and the abundances of functional genes involved in the nitrogen cycle, and methane production and consumption. Overall, results from this study would enhance our comprehension of how soil microorganisms in contrasting farmlands will respond to soil pH changes, and would contribute to more effective soil management and conservation strategies., Importance: This study delves into the impact of soil pH on microbial communities, investigating whether pH directly or indirectly influences bacterial and fungal communities. The research involved two contrasting soils subjected to a 1-2 pH unit amendment. Results indicate bacterial community composition was shaped by soil pH through physiological constraints and nutrient limitations. We found that most taxa relative abundances at the phylum and family levels responded to pH with a quadratic fitting pattern, indicating that soil pH is a reliable predictor. Additionally, soil pH was found to significantly influence the predicted abundance of functional genes involved in the nitrogen cycle as well as in methane production and consumption processes. These insights can contribute to develop more effective soil management and conservation strategies., Competing Interests: The authors declare no conflict of interest.

Mapping of soil nutrient parameters using experimental measurements and geostatistical approaches to assist site-specific fertiliser advisories is anticipated to play a significant role in Smart Agriculture. FarmerZone is a cloud service envisioned by the Department of Biotechnology, Government of India, to provide advisories to assist smallholder farmers in India in enhancing their overall farm production. As a part of the project, we evaluated the soil spatial variability of three potato agroecological zones in India and provided soil health cards along with field-specific fertiliser recommendations for potato cultivation to farmers. Specifically, 705 surface samples were collected from three representative potato-growing districts of Indian states (Meerut, UP; Jalandhar, Punjab and Lahaul and Spiti, HP) and analysed for soil parameters such as organic carbon, macronutrients (NPK), micronutrients (Zn, Fe, Mn, and Cu), pH, and EC. The soil parameters were integrated into a geodatabase and subjected to kriging interpolation to create spatial soil maps of the targeted potato agroecological zones through best-fit experimental semivariograms. The spatial distribution showed a deficiency of soil organic carbon in two studied zones and available nitrogen among all studied zones. The available phosphorus and potassium varied among the agroecological zones. The micronutrient levels were largely sufficient in all the zones except at a few specific sites where nutrient advisories are recommended to replenish. The general management strategies were recommended based on the nutrient status in the studied area. This study clearly supports the significance of site-specific soil analytics and interpolated spatial soil mapping over any targeted agroecological zones as a promising strategy to deliver reliable advisories of fertiliser recommendations for smart farming., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Raising attentions have focused on how to alleviate greenhouse gas (GHG) emissions from orchard system while simultaneously increase fruit production. Microalgae-based biofertilizer represents a promising resource for improving soil fertility and higher productivity. However, the effects of microalgae application more especially live microalgae on GHG emissions are understudied. In this study, fruit yield and quality, GHG emissions, as well as soil organic carbon and nitrogen fractions were examined in a hawthorn orchard, under the effects of live microalgae-based biofertilizer applied at three doses and two modes. Compared with conventional fertilization, microalgae improved hawthorn yield by 15.7%-29.6% with a maximal increment at medium dose by root application, and significantly increased soluble and reducing sugars contents at high dose. While microalgae did not increase GHG emissions except for nitrous oxide at high dose by root application, instead it significantly increased methane uptake by 1.5-2.3 times in root application. In addition, microalgae showed an increasing trend in soil organic carbon content, and significantly increased the contents of soil dissolved organic carbon and microbial biomass carbon, as well as soil ammonium nitrogen and dissolved organic nitrogen at medium dose with root application. Overall, the results indicated that the live microalgae could be used as a green biofertilizer for improving fruit yield without increasing GHG emissions intensity and the comprehensive greenhouse effect, in particular at medium dose with root application. We presume that if lowering chemical fertilizer rates, application of the live microalgae-based biofertilizer may help to reduce nitrous oxide emissions without compromising fruit yield and quality., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Ma et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Global patterns in soil microbiomes are driven by non-linear environmental thresholds. Fertilization is known to shape the soil microbiome of terrestrial ecosystems worldwide. Yet, whether fertilization influences global thresholds in soil microbiomes remains virtually unknown. Here, utilizing optimized machine learning models with Shapley additive explanations on a dataset of 10,907 soil samples from 24 countries, we discovered that the microbial community response to fertilization is highly dependent on environmental contexts. Furthermore, the interactions among nitrogen (N) addition, pH, and mean annual temperature contribute to non-linear patterns in soil bacterial diversity. Specifically, we observed positive responses within a soil pH range of 5.2-6.6, with the influence of higher temperature (>15°C) on bacterial diversity being positive within this pH range but reversed in more acidic or alkaline soils. Additionally, we revealed the threshold effect of soil organic carbon and total nitrogen, demonstrating how temperature and N addition amount interacted with microbial communities within specific edaphic concentration ranges. Our findings underscore how complex environmental interactions control soil bacterial diversity under fertilization., (© 2024 John Wiley & Sons Ltd.)

Forest water reclamation is a decades-old practice of repurposing municipal reclaimed water using land application on forests to filter nutrients and increase wood production. However, long-term application may lead to nutrient saturation, leaching, and potential impairment of ground and surface water quality. We studied long-term effects of reclaimed water application on nutrient leaching potential in a four-decade time series of forest water reclamation facilities in northern Idaho. Our approach compared reclaimed water treated plots with untreated control plots at each of the forest water reclamation facilities. We measured soil nitrifier abundance and net nitrification rates and used tension lysimeters to sample soil matrix water and drain gauges to sample from a combination of matrix and preferential flow paths. We determined nutrient leaching as the product of soil water nutrient concentrations and model-estimated drainage flux. There was more than 450-fold increase in nitrifier abundance and a 1000-fold increase in net nitrification rates in treated plots compared with control plots at long-established facilities, indicating greater nitrate production with increased cumulative inputs. There were no differences in soil water ammonium, phosphate, and dissolved organic nitrogen concentrations between control and effluent treatments in tension lysimeter samples. However, concurrent with increased nitrifier abundance and net nitrification, nitrate concentration below the rooting zone was 2 to 4-fold higher and nitrate leaching was 4 to 10-fold higher in effluent treated plots, particularly at facilities that have been in operation for over two decades. Thus, net nitrification and nitrifier abundance assays are likely indicators of nitrate leaching potential. Inorganic nutrient concentrations in drain gauge samples were 2 to 11-fold higher than lysimeter samples, suggesting nutrient losses occurred predominantly through preferential flow paths. Nitrate was vulnerable to leaching during the wet season under saturated flow conditions. Although nitrogen saturation is a concern that should be mitigated at long-established facilities, these forest water reclamation facilities were able to maintain average soil water nitrate concentrations to less than 2 mg L -1 , so that nitrogen and phosphorous are effectively filtered to below safe water standards., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Green manure with appropriate amount of chemical nitrogen fertilizer can increase crop yield, but also aggravate soil carbon emissions. However, it is unclear whether incorporation of green manure into the cropping pattern with reduced nitrogen amount can alleviate this situation and enhance carbon sequestration potential. So, a field experiment with split-plot design was set up in 2018 of northwest China, and studied the effects of nitrogen reduction on crop productivity, carbon emissions, and carbon sequestration potential in 2021-2023. The main plots were two cropping patterns, including multiple cropped green manure after wheat harvest (W-G) and fallow after wheat harvest (W). Three nitrogen application levels formed the split-plots, including local conventional nitrogen amount (N3, 180 kg ha -1 ), nitrogen amount reduced by 15% (N2, 153 kg ha -1 ) and 30% (N3, 126 kg ha -1 ). The results showed that W-G increased grain yield of wheat and energy yield of wheat multiple cropped green manure pattern. The multiple cropped green manure after wheat harvest with local conventional nitrogen amount reduced by 15% (W-GN2) had the significant increasing-effect, and increased grain yield of wheat by 9.6% and increased total energy yields by 39.3% compared to fallow after wheat harvest with local conventional nitrogen amount (W-N3). Relative to W-N3, W-GN2 did not significantly increase carbon emissions of wheat season, and increased total carbon emissions of cropping pattern by 11.1%. Compared to multiple cropped green manure after wheat harvest with local conventional nitrogen amount (W-GN3), W-GN2 decreased carbon emissions by 5.8% in wheat season and decreased by 3.9% in the whole cropping pattern. Therefore, W-GN2 gained high carbon emission efficiency based on grain yield, and were 9.9% and 11.2% higher than W-N3 and W-GN3, respectively. In addition, W-GN2 enhanced soil total nitrogen, carbon, and organic carbon contents, compared with W-N3, thus increasing soil carbon sequestration potential index (net primary productivity/carbon emissions). We conclude that multiple cropped leguminous green manure after wheat harvest with local conventional nitrogen amount reduced by 15% can enhance crop productivity and carbon sequestration potential of farmland in arid areas., Competing Interests: Declaration of competing interest The authors declared that they have no conflicts of interest to this work., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Chemical coagulation has gained recognition as an effective technique to enhance the removal efficiency of pollutants in wastewater prior to their entry into a constructed wetland (CW) system. However, its potential impact on the chemical and microbial properties of soil and plant systems within CWs requires further research. This study investigated the impact of using ferric chloride (FeCl 3 ) as a pre-treatment stage for dairy wastewater (DWW) on the chemical and microbial properties of water-soil-plant systems of replicated pilot-scale CWs, comparing them to CWs treating untreated DWW. CWs treating amended DWW had better performance than CWs treating raw DWW for all water quality parameters (COD, TSS, TP, and TN), ensuring compliance with the EU wastewater discharge directives. Soil properties remained mostly unaffected except for pH, calcium and phosphorus (P), which were lower in CWs treating amended DWW. As a result of lower nitrogen (N) and P loads, the plants in CWs receiving FeCl 3 -amended DWW had lower N and P contents than the plants of raw DWW CWs. However, the lower loads of P into amended DWW CWs did not limit the growth of Phragmites australis, which were able to accumulate trace elements higher than CWs receiving raw DWW. Alpha and Beta-diversity analysis revealed minor differences in community richness and composition between both treatments, with only 3.7% (34 genera) showed significant disparities. Overall, the application of chemical coagulation produced superior effluent quality without affecting the properties of soil and plant of CWs or altering the functioning of the microbial community., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Ahmed Mohammad reports financial support was provided by Teagasc. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Winter wheat (Triticum aestivum, L.) production in the semi-arid US Northern High Plains (NHP) is challenged by frequent droughts and water-limited, low fertility soils. Composted cattle manure (compost) and cover crops (CC) are known to provide agroecosystem services such as improved soil health, and in the CC case, increased plant diversity, and competition with weedy species. The main concern of planting CC in winter wheat fallow rotation in regions that are more productive than the NHP, however, is the soil moisture depletion. It is unknown however, whether addition of CC to compost-amended soils in the NHP will improve soil properties and agroecosystem health without compromising already low soil water content. The main objective of this study was to assess the effects of four CC treatments amended with compost (45 Mg ha-1) or inorganic fertilizer (IF) (.09 Mg ha-1 mono-ammonium phosphate, 11-52-0 and 1.2 Mg ha-1ammonium sulfate, 21-0-0) on the presence of weeds, soil and plant total carbon (C), nitrogen (N), and biological dinitrogen (N2) fixation (BNF). Mycorrhizal Mix (MM), Nitrogen Fixer Mix (NF), Soil Building Mix (SB), a monoculture of phacelia (Phacelia tanacetifolia Benth L.) (PH), and a no CC control (no CC) were grown in native soil kept at 7% soil moisture in a greenhouse for a period of nine weeks. When amended with compost, MM was the most beneficial (48 g m-2 BNF and 1.7% soil C increase). SB had the highest germination, aboveground biomass, and decreased weed biomass by 60%. It also demonstrated the second highest amount of BNF (40 g m-2) and soil C increase by 1.5%. On contrary, IF hindered BNF by almost 70% in all legume-containing CC treatments and reduced soil C by 15%., Competing Interests: The authors have declared that no competing interests exist., (Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.)

Mismanagement of the nitrogen (N) fertilization in agriculture leads to low N use efficiency (NUE) and therefore pollution of waters and atmosphere due to NO 3 - leaching, and N 2 emissions. The use of N simulation models of the soil-plant system can help improve the N fertilizer management increasing NUE and decreasing N pollution issues. However, many N simulation models lack balance between complexity and uncertainty with the result that they are not applied in actual practice. The NITIRSOIL is a one-dimensional transient-state model with a monthly time step that aims at addressing this lack in the estimation of, mainly, dry matter yield (DMY), crop N uptake (N 3 ), soil mineral N (N upt ), soil mineral N (N min ), and NO 3 - leaching and soil N upt , NO 3 - leaching and soil N min at crop season end. Therefore, the NITIRSOIL model can be used in actual practice to improve the sustainability of the N management in, particularly horticulture, due to the balance it features between complexity and prediction uncertainty. For this aim, the NITRISOIL can be used either on its own, or in combination with "Nmin" on-site N fertilization recommendation methods, or even could be implemented as the calculation core of decision support systems., Competing Interests: Declaration of competing interest The authors declare that they had no conflicts of interest in doing this research., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Soil nitrogen (N) fixation, driven by microbial reactions, is critical to support the entrance of nitrogen in nutrient poor and pioneer ecosystems. However, how and why N fixation and soil diazotrophs evolve as forests develop remain poorly understood. Here, we used a 60-year forest rewilding chronosequence and found that soil N fixation activity gradually decreased with increasing forest age, experiencing dramatic drops of 64.8% in intermediate stages and 93.0% in the oldest forests. Further analyses revealed loses in diazotrophic diversity and a significant reduction in the abundance of important diazotrophs (e.g., Desulfovibrio and Pseudomonas) as forest develops. This reduction in N fixation, and associated shifts in soil microbes, was driven by acidification and increases in N content during forest succession. Our results provide new insights on the life history of one of the most important groups of soil organisms in terrestrial ecosystems, with consequences for understanding the buildup of nutrients as forest soil develops., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

Integrated nutrient management and crop rotation are important farming practices, which enhance the nutrient use efficiency of crops and reduce the incidence of diseases and insect pests. The study was carried out to address the gap in using integrated nutrient management in crop rotation systems for soil qualities and crop yield improvement. That was done by adjusting the balance ratio of dry bio-slurry and nitrogen fertilizers. The experiment was containing ten levels; Control (0,0), recommended nitrogen, 50% dry-bio slurry, 100% dry-bio slurry, 75% dry-bio slurry, 75% dry-bio slurry+25% recommended nitrogen, 50% dry-bio slurry+50% recommended nitrogen, 25% dry-bio slurry+75% recommended nitrogen, 100% dry-bio slurry + 25% recommended nitrogen and 100% dry-bio slurry + 50% recommended nitrogen that was laid out in randomized complete block design with three replications for three years. The data on soil properties and yield components of potatoes and wheat were collected and analyzed using statistical analysis system software 9.4. An application of dry bio-slurry with nitrogen fertilizer was significantly affected both crop yield and soil properties in the rotation system. The application of 25% dry bio-slurry with 75% recommended nitrogen gave the highest tuber yield of potato (27.6 tha-1) as compared to control. Similarly, using 100% and 75% sole dry bio-slurry resulted in the highest grain yield (3.85 tha-1) and above-ground biomass (9.59 tha-1) of wheat. The combination of 25% dry bio-slurry with 75% recommended nitrogen scored the highest net benefit (2889.2 US$) with an acceptable marginal return (4463.3%) via by improving crops yield in the system. So, an application of 25% dry bio-slurry with 75% recommended nitrogen could be promoted for yield-soil improvement in the study area and similar agroecology., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Addis et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The conversion of farmland to forest in China has been recognized for its positive impact on above-ground vegetation and carbon sequestration. However, the impact on soil quality during land conversion, particularly in vulnerable karst areas, has received less attention. In this study conducted in a karst area of southwest China, eight different farmland conversion strategies were investigated to assess improvements in surface soil carbon, nitrogen, and ecosystem multi-functionality (EMF). Our results showed that farmland converted to afforestation areas or farmland that was abandoned contained higher amounts of carbon (total, organic, active) and ammonium nitrogen (NH 4 -N) in the soil compared to farmland converted to grassland or maize crop. Soluble organic carbon levels were higher in afforestation and grassland areas compared to maize crop controls. By contrast, soil from grassland and abandoned land exhibited higher levels of nitrate nitrogen (NO + -N) in the soil compared to farmland converted to grassland or maize crop. Soluble organic carbon levels were higher in afforestation and grassland areas compared to maize crop controls. By contrast, soil from grassland and abandoned land exhibited higher levels of nitrate nitrogen (NO 3 -N content between any condition, except for afforestation land that specifically contained the Zenia insignis plant species. Afforestation land consistently exhibited higher EMF values than grassland. Pearson correlation analysis revealed positive relationships between soil indices and EMF scores, except for NO - -N.Random forest analysis explained 95% of the variation in soil EMF and identified specific soil factors: total carbon, organic carbon, active labile organic carbon, total nitrogen, and ammonium nitrogen, as the main drivers of soil multi-functionality. Our studies show how various reforestation strategies can enhance soil nutrient sequestration and improve soil multi-functionality of farmland in the karst areas.These findings provide insight into sustainable soil management practices for converting farmland into natural areas.4 + -N content between any condition, except for afforestation land that specifically contained the Zenia insignis plant species. Afforestation land consistently exhibited higher EMF values than grassland. Pearson correlation analysis revealed positive relationships between soil indices and EMF scores, except for NO 3 - -N.Random forest analysis explained 95% of the variation in soil EMF and identified specific soil factors: total carbon, organic carbon, active labile organic carbon, total nitrogen, and ammonium nitrogen, as the main drivers of soil multi-functionality. Our studies show how various reforestation strategies can enhance soil nutrient sequestration and improve soil multi-functionality of farmland in the karst areas.These findings provide insight into sustainable soil management practices for converting farmland into natural areas., (© 2024. The Author(s).)

Soil extractable nitrate, ammonium, and organic nitrogen (N) are essential N sources supporting primary productivity and regulating species composition of terrestrial plants. However, it remains unclear how plants utilize these N sources and how surface-earth environments regulate plant N utilization. Here, we establish a framework to analyze observational data of natural N isotopes in plants and soils globally, we quantify fractional contributions of soil nitrate (f NO3- ), ammonium (f NH4+ ), and organic N (f EON ) to plant-used N in soils. We find that mean annual temperature (MAT), not mean annual precipitation or atmospheric N deposition, regulates global variations of f NO3- , f NH4+ , and f EON . The f NO3- increases with MAT, reaching 46% at 28.5 °C. The f NH4+ also increases with MAT, achieving a maximum of 46% at 14.4 °C, showing a decline as temperatures further increase. Meanwhile, the f EON gradually decreases with MAT, stabilizing at about 20% when the MAT exceeds 15 °C. These results clarify global plant N-use patterns and reveal temperature rather than human N loading as a key regulator, which should be considered in evaluating influences of global changes on terrestrial ecosystems., (© 2024. The Author(s).)

Soil extracellular enzyme plays a vital role in changing soil nitrogen (N) mineralization of rice field. However, the effects of soil extracellular enzyme activities (EEA) and microbial community composition response to N mineralization of rice field under short-term tillage treatment needed to be further explored. In this study, we investigated the impact of short-term (8-year) tillage practices on rhizosphere soil N transformation rate, soil enzyme activities, soil microbial community structure, and the N mineralization function gene abundances in double-cropping rice field in southern China. The experiment consisted of four tillage treatments: rotary tillage with crop straw input (RT), conventional tillage with crop straw input (CT), no-tillage with crop straw retention (NT), and rotary tillage with all crop straw removed as a control (RTO). The results indicated that the rhizosphere soil N transformation rate in paddy field under the NT and RTO treatments was significantly decreased compared to RT and CT treatments. In comparison to the NT and RTO treatments, soil protease, urease, β -glucosaminidase, and arginase activities were significantly improved by the CT treatment, as were abundances of soil sub , npr , and chiA with CT and RT treatments. Moreover, the overall diversity of soil bacterial communities in NT and RTO treatments was significantly lower than that in RT and CT treatments. Soil chitinolytic and bacterial ureolytic communities were also obviously changed under a combination of tillage and crop straw input practices.

In order to evaluate the effects of continuous cropping of millet on soil nutrients and soil enzyme activities, the present study was based on four treatments of 2 years of continuous cropping (T1), 3 years of continuous cropping (T2), 4 years of continuous cropping (T3) and rotational cropping (CK), based on 4 years of no fertilizer positioning experiments, and the soil nutrients, soil enzyme activities and millets yields were determined, respectively. The results showed that with the increase of continuous cropping years, the millet yield decreased and was significantly lower than that of rotating with legume crops, and compared with CK, the yields of T1, T2 and T3 treatments were reduced by 8.92%, 13.73% and 37.60%, respectively; the soil nitrogen and phosphorus contents were reduced, the quick-acting potassium content did not change obviously, and the soil pH was increased; Soil urease, alkaline phosphatase, sucrase and catalase activities generally showed a decreasing trend and the decrease was more significant with the increase in the number of years of continuous cropping. Therefore, in order to maintain the soil fertility and increase the millet yield, it is necessary to practice crop rotation and stubble reversal between millets and leguminous crops such as kidney beans, and to apply certain fertilizers., (© 2024. The Author(s).)

Soil degradation, marked by declining organic matter, threatens global food security. The impact of brewer's spent yeast (BSY) on clay and sand was analysed at varying application rates to assess its effectiveness in improving soil quality. A randomized complete block design with three replicates was employed. One kilogram of soil were mixed with BSY at application rates of 2 t/ha and 5 t/ha. The samples were incubated at 26 °C for 5 months with daily watering. We analysed pH, total nitrogen, organic carbon, total phosphorus, and electrical conductivity (EC); microbial activity (total heterotrophic bacteria, actinobacteria, and fungi) and soil enzyme activity (dehydrogenase, catalase, protease). BSY application improved soil quality, particularly in clay. Clay showed increased in pH, EC, N and C. BSY significantly boosted microbial populations (bacteria, fungi) in clay with a lesser effect in sand. Enzyme activity and a fertility index also improved in BSY-treated clay, while sand displayed increased activity of a different enzyme. Results suggest BSY holds promise as an organic fertilizer, especially for clay soils. Further research is needed to optimize application, understand long-term effects, and evaluate economic feasibility and social acceptance. This study contributes to the search for sustainable, local solutions to improve soil health and agricultural practices., (© 2024. The Author(s).)

The swift proliferation of forests converted into monoculture plantations has profound impacts on soil nutrients, microbial communities, and many ecological processes and functions. Nematodes are soil microfauna that play a pivotal role in biogeochemical cycling and in soil food web, whereas the response of soil nematode communities and energy flows to forest conversion remains unknown. Here, we assessed the community composition and the energy flows of the nematode food webs as a function of soil chemistry after conversion from natural forests (Forest) to four plantations (8-year-old): Amygdalus persica (Peach), Myrica rubra (Berry), Camellia oleifera (Oil), and Cunninghamia lanceolata (Fir). After forest conversion, soil organic carbon (SOC) and total nitrogen (TN) contents decreased by 65 % and 55 %, respectively. Forest conversion strongly reduced the abundance (particularly large-bodied omnivorous-predatory nematodes), diversity, maturity, and stability of the soil nematode community. The shifts in composition and structure of nematode communities after forest conversion are reflected in changes in the abundance of predominant genera and trophic taxa, especially bacterivorous, fungivorous, and omnivorous-predatory nematodes. Acrobeloides notably increased, whereas Plectus, Prismatolaimus, Tylencholaimus, and Tripyla decreased. Accordingly, the abundances of r-strategy nematodes (cp value = 1-2) increased, but that of the K-strategists (cp value = 3-5) declined. Additionally, the energy flow across the soil nematode food web was reduced by 36 % and flow uniformity declined by 24 % after forest conversion. These changes in nematode diversity and abundance were triggered by diminishing soil C and N contents, thereby affecting the energy flows via the nematode food webs. Thus, forest conversion affects soil biotas and multi-functions from the perspective of nematode food web structure and energy flows, and underlines the interconnections between ecosystem and energy dynamics across multi-trophic levels, which is crucial for sustainable forest management., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

To understand the effects of nitrogen deposition on element cycling and nutrient limitation status in forest ecosystems, we examined the effects of nitrogen deposition on the stoichiometric characteristics of forest soil-microbial-extracellular enzymes in Pinus yunnanensis forest. We conducted a field experiment with control (CK, 0 g N·m -2 ·a -1 ), low nitrogen (LN, 10 g N·m -2 ·a -1 ), medium nitrogen (MN, 20 g N·m -2 ·a -1 ) and high nitrogen (HN, 25 g N·m -2 ·a -1 ) since 2019. We collected soil samples (0-5 cm, 5-10 cm and 10-20 cm) at September 2022, and measured the contents of soil organic, total nitrogen, total phosphorus, microbial biomass carbon, nitrogen and phosphorus (MBC, MBN, MBP) and the activities of C, N, and P acquisition enzymes. The results showed that nitrogen deposition significantly reduced soil organic content, C:N and C:P by 6.9%-29.8%, 7.6%-45.2% and 6.5%-28.6%, and increased soil total N content and N:P by 10.0%-45.0% and 19.0%-46.0%, respectively. Nitrogen addition did not affect soil total P content. Except for soil C:N and C:P, soil nutrient content and stoichiometric ratio were highest in 0-5 cm soil layer. MN and HN treatments significantly decreased MBN by 11.0%-12.7%. MBC, MBP, and their stoichiometry did not change significantly under nitrogen deposition. Soil microbial nutrient content in 0-5 cm soil layer was significantly higher than that in other soil layers. Nitrogen deposition significantly decreased the activities of cellobiose hydrolase and leucine aminopeptidase (decreased by 14.5%-16.2% and 48.7%-66.3%). HN treatment promoted β-1,4-glucosidase activity (increased by 68.0%), but inhibited soil enzyme stoichiometric carbon to nitrogen ratio and nitrogen to phosphorus ratio (decreased by 95.4% and 88.4%). LN and MN treatment promoted β-1,4-N-acetylglucosaminidase activity (increased by 68.3%-116.6%), but inhibited enzyme stoichiometric carbon to phosphorus ratio (decreased by 14.9%-29.4%). Alkaline phosphatase activity had no significant change. Soil enzyme activities were significantly decreased with increasing soil depth. Soil total N and total P and microbial nutrients were negatively correlated with vector angle (representing microbial nitrogen or phosphorus limitation), while vector length (representing microbial carbon limitation) was consistently significantly positively correlated with vector angle, suggesting the synergistic promotion between microbial carbon limitation and phosphorus limitation. Nitrogen deposition gradually shifted to phosphorus limitation while alleviating microbial nitrogen limitation in P. yunnanensis forest. In addition, microbial activities in this region was limited by C availability, and the relationship between microbial C and P limitation was proportional.

Studying the stoichiometric characteristics of soil nutrients aids in evaluating soil quality and deciphering the coupling of soil nutrients. The influence of migratory bird activities on the dynamics of wetland soil nutrients and their stoichiometric remains unclear. We classified the central, peripheral and adjacent natural grassy areas as severe, mild, and no bird activity (control), respectively, in Donghu Carex meadow, a representative migratory bird habitat in Poyang Lake, based on flock characteristics and initial surveys. We analyzed the contents and stoichio-metry of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) across soil depths of 0-100 cm under different intensities of migratory bird activities. The results showed that the activities of migratory birds significantly impacted nutrient levels exclusively within 0-30 cm soil. Mild activities markedly enhanced SOC and TN across 0-30 cm soil, while both mild and severe activities significantly raised TP within the same depth. For the 0-100 cm soil profiles, soil C/N ratios were 10.0, 10.8, and 9.9, C/P ratios were 23.5, 30.0, and 22.7, and N/P ratios were 2.3, 2.7, and 2.3 under no, mild, and severe bird activities, respectively. Further, mild activities of migratory birds significantly increased soil C/N, C/P and N/P ratios only within the 0-30 cm depth, while the stoichiometric ratios of all soil layer had no significant difference under severe bird activity. Soil stoichiometric ratios strongly correlated with physicochemical properties. SOC, TN, and TP primarily mediated the effects of migratory bird activity on soil carbon, nitrogen, and phosphorus stoichiometric ratios in Poyang Lake wetland. In conclusion, the influence of migratory bird activity on the stoichiometric ratios of soil carbon, nitrogen, and phosphorus in Poyang Lake wetland exhibited depth threshold (approximately 30 cm), aligning with the "Intermediate Distur-bance Hypothesis". These findings could provide a new perspective for the protection of wetlands and migratory birds.

Exploring nutrient limitation in forest soil holds significant implications for forest tending and management. However, current research on nutrient limitation status of microorganisms in Robinia pseudoacacia plantations within the Loess Plateau remains insufficient. To investigate soil microbial nutrient limitation of R. pseu-doacacia plantations on the Loess Plateau, we selected R. pseudoacacia plantations with different afforestation time series (15, 25, 35, and 45 years) and a pile of barren slope cropland (control) in Yongshou County, Shaanxi Province as the research objects. We analyzed the contents of soil organic matter, total nitrogen, and total phosphorus, and the activities of β-1,4-glucosidase (BG), cellobiose hydrolase (CBH), leucine aminopeptidase (LAP), β-1,4-N-acetylglucoside (NAG) and phosphatase (AP). We analyzed the soil nutrient limitation by stoichiometry and enzyme metrology. The results showed a shift in soil pH from alkaline to acidic during vegetation restoration process, and that total phosphorus exhibited a gradual decrease over the course of 0 to 25 years. Soil orga-nic matter, total nitrogen and enzyme activities exhibited an increasing trend during the same time frame. However, between 25 and 45 years of age, soil total phosphorus, soil organic matter, total nitrogen, AP and LAP gradually declined while NAG, BG, and CBH initially increased and then decreased. Notably, the values of (BG+CBH)/(LAP+NAG), (BG+CBH)/AP and (LAP+NAG)/AP in R. pseudoacacia plantations were higher than the global average throughout the process of vegetation restoration. In the study area, the vector length was less than 1 and gradually increased, indicating that a progressive increase in microbial carbon limitation during the process of vegetation restoration. The vector angle exceeded 45° and exhibited an overall decreasing trend, suggesting that soil microorganisms were constrained by phosphorus (P) with a gradual deceleration of P limitation, without any nitrogen (N) limitation. The restoration of R. pseudoacacia plantation resulted in significant change in soil physical and chemical properties, while the time series of afforestation also influenced nutrient limitation of soil microorganisms.

In the dryland area of the Loess Plateau in northwest China, long-term excessive fertilization has led to soil compaction and nutrient loss, which in turn limits crop yield and soil productivity. To address this issue, we conducted experiments using environmentally friendly organic fertilizer and bacterium fertilizer. Our goal was to investigate the effects of additional organic and bacterium fertilizer inputs on soil water migration, crop root architecture, and yield formation. We implemented six different fertilizer strategies, namely: Nm (mulching, N 30 kg/ha), NPK1m (mulching, N 60 kg/ha; P 30 kg/ha; K 30 kg/ha), NPK2m (mulching, N 90 kg/ha; P 45 kg/ha; K 30 kg/ha), NPKOm (mulching, N 90 kg/ha; P 45 kg/ha; K 30 kg/ha; organic fertilizer 2 t/ha), NPKBm (mulching, N 60 kg/ha; P 30 kg/ha; K 30 kg/ha; bacterium fertilizer 10 kg/ha), and N (N 30 kg/ha; no mulching). The results revealed that the addition of bacterium fertilizer (NPKBm) had a positive impact on soybean root system development. Compared with the other treatments, it significantly increased the total root length, total root surface area, and total root length density by 25.96% ~ 94.89%, -19.63% ~ 36.28%, and 9.36% ~ 28.84%, respectively. Furthermore, NPKBm enhanced soil water consumption. In 2018, water storage during the flowering and podding periods decreased by 12.63% and 19.65%, respectively, while water consumption increased by 0.97% compared to Nm. In 2019, the flowering and harvest periods decreased by 23.49% and 11.51%, respectively, while water consumption increased by 0.65%. Ultimately, NPKBm achieved high grain yield and significantly increased water use efficiency (WUE), surpassing other treatments by 76.79% ~ 78.97% and 71.22% ~ 73.76%, respectively. Subsequently, NPK1m also exhibited significant increases in yield and WUE, with improvements of 35.58% ~ 39.27% and 35.26% ~ 38.16%, respectively. The use of bacterium fertilizer has a profound impact on soybean root architecture, leading to stable and sustainable grain yield production., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Liu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)