Abstract The long-term effects of conservation agriculture on soil physical and chemical properties and their relationship with crop yields are still relatively poorly understood. In addition, the effects of those practices ranged widely depending on climatic and edaphic conditions and so they cannot be generalized for all agro-ecological regions and crop types. This study evaluates the effects of three conservation agriculture practices - reduced tillage (RT), reduced tillage plus incorporation of green manure (RTG), and no-tillage (NT) - on the soil quality on almond orchards under semiarid conditions and the soil factors explaining crop yield under these management practices. The soil physical indicators used were bulk density, resistance to penetration, total porosity, air capacity, relative field capacity, available water content, infiltration rate and field plant-available water content. The chemical parameters evaluated were soil organic carbon, total nitrogen, nitrate, and available phosphorus. Changes in the soil physical properties with the incorporation of green manure and with no-tillage, relative to RT were, mainly detected in the 5−15 cm soil layer, where improvements in soil water availability were observed. In addition, there was a positive effect of both green manure and no-tillage on the infiltration rate relative to RT. The shift from RT to RTG led to an improvement in total soil organic carbon and nitrogen, resulting in a positive effect on crop yield after six years of implementation. No-tillage led to a decline of about 70 % in crop yield with respect to the tillage treatments, despite the improvement in the soil available water content from the first year of its adoption. However, a strong decrease in the concentrations of available nitrogen was the factor mainly responsible for the crop yield reductions under NT.

中文翻译：

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可持续管理实践对雨养地中海杏仁农业生态系统土壤特性和作物产量的长期影响

摘要 保护性农业对土壤理化性质的长期影响及其与作物产量的关系仍知之甚少。此外，这些做法的影响范围很大，取决于气候和土壤条件，因此它们不能适用于所有农业生态区域和作物类型。本研究评估了三种保护性农业实践 - 减耕 (RT)、减耕加绿肥 (RTG) 和免耕 (NT) - 对半干旱条件下杏仁园土壤质量和土壤因素的影响解释这些管理实践下的作物产量。使用的土壤物理指标是容重、抗渗透性、总孔隙度、空气容量、相对田间持水量、有效水含量、渗透率和田间植物有效水含量。评估的化学参数是土壤有机碳、总氮、硝酸盐和有效磷。相对于 RT，掺入绿肥和免耕的土壤物理性质的变化主要在 5-15 cm 土层中检测到，在那里观察到土壤水分可用性的改善。此外，相对于 RT，绿肥和免耕对渗透率都有积极影响。从 RT 到 RTG 的转变导致土壤有机碳和氮总量的改善，在实施六年后对作物产量产生了积极影响。相对于耕作处理，免耕导致作物产量下降约 70%，尽管从其采用的第一年起土壤可用水含量有所改善。然而，有效氮浓度的大幅下降是导致 NT 下作物产量下降的主要原因。