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Purpose: Tillage practices and crop growth play important roles in the soil erosion of sloping farmland. This study aims to investigate the effects of tillage practices on soil erosion in response to different crop growth stages and to determine the primary factors that affected the runoff reduction benefit of tillage practices among different growth stages. Methods: A field study was carried out under natural rainfall conditions, and 12 runoff plots (20 m × 5 m) were established, including four treatments, i.e., flat planting (FP), flat planting with hedgerow intercropping (HG), longitudinal ridge (LR) and bare land (CK). Runoff and soil losses after each rainfall event were monitored during the peanut seasons of 2021 and 2022 and the effects of tillage practices and peanut growth stages on runoff and sediment yields were evaluated. Results: The total surface runoff depth and sediment yield decreased in the following order: CK > LR > FP > HG. As peanuts grew, the seedling, needling, podding, and full fruit stages contributed approximately 71.5%, 20.4%, 6.4%, and 1.7% of the total runoff depth, respectively, which could be attributed to the synergistic impact of rainfall, crop growth, and antecedent soil moisture. During the seedling stage of peanuts, which did not provide sufficient surface cover, concentrated rainfall in large amounts resulted in high soil moisture and consequently high runoff losses. As peanuts grew, the S-shaped growth curve for peanut aboveground parts and root systems and reduced rainfall depth and frequency resulted in less runoff loss and increased runoff reduction benefits of tillage practices. Conclusions: The early growth stage of peanuts, generally accompanied by high antecedent soil moisture and heavy rainfall, should attract more attention to improving water erosion conditions on sloping farmland with only longitudinal ridges. [ABSTRACT FROM AUTHOR]

Purpose: Changes in climate and land use may disrupt the soil carbon (C), nitrogen (N), and phosphorus (P) cycles, which affect the availability of essential nutrients differently, including soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP). Nevertheless, lithologic impact on soil C:N:P stoichiometry over a broad climatic gradient remains largely unknown. We aimed to determine the variation in nutrient limitations between karst and non-karst forests and croplands across a climate gradient. Materials and methods: This study investigated soil C:N:P stoichiometry in mature forest (MF) and nearby cropland rotation (CR) (as a control) soils on limestone (karst) and clastic rock (non-karst) throughout a climatic gradient in southwest China through analysis of soil samples. Result and discussion: The SOC and TN contents in the karst MF were 1.3 and 1.6 times greater, respectively, than that in the non-karst MF. Consequently, the karst MF had a lower C:N ratio than did the non-karst MF. The SOC and TN contents were considerably higher in the MF than they were in the CR under both lithologies, leading to higher C:P and N:P ratios in the MF compared to those in the CR. The increasing temperature resulted in a shift from TN and TP to SOC limitation, due to the increased decomposition of SOC by microbes with an increase in temperature. Soil pH and Ca content are controlled by the lithology, and they were closely related to C:N:P stoichiometry in this study, whereas a combination of lithology and temperature controlled soil microbial activity and plant growth. Importantly, the magnitude of lithology-induced changes in the stoichiometry was greater as temperature increased, which was more pronounced in the non-karst than it was in the karst. Conclusions: These findings highlight the responses of soil C, N, and P to climate warming in relation to stoichiometry, and soil-microorganism-plant response strategies may be the key to the mitigating the effect of temperature increase on nutrient cycles in karst ecosystems. [ABSTRACT FROM AUTHOR]

Background and aims: Trait-based approaches are increasingly used to improve ecological restoration in degraded ecosystems. The aim of this study was to evaluate how vegetation controls soil detachment capacity (Dc) by concentrated flow based on the linkages between root traits and soil physics. Methods: We selected 60 plots along a land degradation gradient caused by long-term water erosion in a small catchment, central China. These plots consisted of woodlands, scrublands, grasslands and bare lands. And soil physical properties, root traits and Dc were measured in each plot. Results: Fine roots (0.2 mm < diameter < 2 mm) accounted for 51–93% of total root length in topsoil. Roots explained most of the soil variations in noncapillary porosity, aggregate stability and shear strength. Furthermore, our prediction model (R2 = 0.88, NSE = 0.85) showed that fine roots length density and soil shear strength were the primary factors reducing Dc. Conclusions: Vegetation restoration improves multiple soil physical properties key to mitigating Dc, and the root functional traits play a substantial role in this relationship. These findings could provide the basis for soil conservation, and for expanding the pool of species of interest, which can be used to provide erosion mitigation services in degraded ecosystems. [ABSTRACT FROM AUTHOR]