Cover crops are a potential component of agroecological cropping systems, since they may render crop rotations more sustainable. They simultaneously provide multiple ecosystem services, such as decreasing nitrate leaching, decreasing erosion, and increasing soil organic matter. However, cover crops increase evapotranspiration and reduce drainage, which results in a potential disservice for groundwater recharge. Little attention has focused on management of cover crop residues after destruction or their influence on water flux dynamics, particularly in dry and temperate climates. The objective of our study was to analyze and quantify the impact of cover crop management on soil water content and water flux dynamics to understand the main mechanisms of system functioning. We combined a two-year field experiment with crop-model simulations. We performed the field experiment in southwestern France that compared three cover crop treatments, with bare soil as the control. The treatments included (1) living cover crops lasting ca. 9 months from August-April, (2) crushing cover crops in November and leaving them as mulch on the soil, and (3) plowing up cover crops in November to promote residue decomposition and the green manure effect. The STICS soil-crop model was used to predict water fluxes that were not measured and to perform a 20-year independent simulation study based on recent climate series for the experimental site. Our main results indicated that cover crops (1) always reduce water drainage by 20-60 mm compared to that under bare soil; and (2) could significantly reduce soil water content (0-120 cm deep) for the next cash crop by a mean of 20-50 mm, and up to 80 mm in dry spring conditions, but early destruction could decrease this negative impact. The simulations clearly showed that the interaction between climate variability, i.e., rainfall distribution during the fallow period, and cover crop management should be considered to explain the impact of inter-annual variability on the water balance. Thus, destroying cover crops mechanically in late autumn and retaining the residues as mulch could be a good compromise between the multiple services the cover crop provides during the fallow period and avoiding the negative impact on soil water availability for the next cash crop.

中文翻译：

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由于降雨分布和管理之间的相互作用，覆盖作物减少排水，但并不总是土壤含水量

覆盖作物是农业生态种植系统的潜在组成部分，因为它们可能使作物轮作更具可持续性。它们同时提供多种生态系统服务，例如减少硝酸盐浸出、减少侵蚀和增加土壤有机质。然而，覆盖作物会增加蒸发蒸腾并减少排水，这可能会对地下水补给造成不利影响。很少关注被破坏后的覆盖作物残留物的管理或其对水通量动态的影响，特别是在干燥和温带气候中。我们研究的目的是分析和量化覆盖作物管理对土壤含水量和水通量动态的影响，以了解系统功能的主要机制。我们将为期两年的田间试验与作物模型模拟相结合。我们在法国西南部进行了田间试验，比较了三种覆盖作物处理，裸土作为对照。处理包括 (1) 活覆盖作物持续约。8-4 月 9 个月，(2) 11 月碾碎覆盖作物，将其作为覆盖物留在土壤中，(3) 11 月翻耕覆盖作物，以促进残留物分解和绿肥效果。STICS 土壤作物模型用于预测未测量的水通量，并根据试验场最近的气候系列进行 20 年独立模拟研究。我们的主要结果表明，与裸土相比，覆盖作物 (1) 总是减少 20-60 毫米的排水量；(2) 可以显着降低下一经济作物的土壤含水量（0-120 厘米深），平均减少 20-50 毫米，在干燥的春季条件下可达 80 毫米，但早期破坏可以减少这种负面影响。模拟清楚地表明，应考虑气候变率（即休耕期间的降雨分布）与覆盖作物管理之间的相互作用，以解释年际变率对水平衡的影响。因此，在深秋机械破坏覆盖作物并将残留物保留为覆盖物可能是覆盖作物在休耕期间提供的多种服务和避免对下一个经济作物的土壤水分可用性的负面影响之间的良好折衷。应考虑覆盖作物管理来解释年际变化对水平衡的影响。因此，在深秋机械破坏覆盖作物并将残留物保留为覆盖物可能是覆盖作物在休耕期间提供的多种服务和避免对下一个经济作物的土壤水分可用性的负面影响之间的良好折衷。应考虑覆盖作物管理来解释年际变化对水平衡的影响。因此，在深秋机械破坏覆盖作物并将残留物保留为覆盖物可能是覆盖作物在休耕期间提供的多种服务和避免对下一个经济作物的土壤水分可用性的负面影响之间的良好折衷。