Cover crops can be utilized to lower soil nitrate leaching. However, depending on the species grown and cover crop termination management, this may lead to nitrogen (N) immobilization and/or depletion of soil moisture available to the following cash crop, potentially impacting on crop yields. Cover crop management is also dependent on using herbicides to terminate growth prior to planting the next crop. We used an alternative method for cover crop termination by capitalizing on plant senescence by frost in a multi-species cover crop established over winter between wheat and maize. The cover crops accumulated greater quantities of N than the control. However, upon cover crop senescence due to cold temperatures, the partially terminated cover crop significantly increased topsoil available N from December to late February. This available N in the topsoil could be susceptible to leaching although this was not observed in our study. Cover crops did not have a significant prolonged effect on soil moisture over winter and late spring. The following maize yields were not significantly different between the control and cover crop treatment. Frost-sensitive cover crop species could not be reliably terminated under a temperate climate, but provided a continuous supply of soil available N as the plants senesced. Depending on the soil moisture and weather conditions in the spring, there could be a N leaching risk although this could be mitigated by establishing early spring crops.

中文翻译：

---

使用对霜敏感的覆盖作物及时进行氮矿化和土壤水分管理

覆盖作物可用于降低土壤硝酸盐浸出。然而，根据种植的物种和覆盖作物终止管理，这可能导致氮 (N) 固定和/或可用于后续经济作物的土壤水分耗尽，从而可能影响作物产量。覆盖作物管理还依赖于在种植下一作物之前使用除草剂终止生长。我们使用了另一种方法来终止覆盖作物，通过在冬季在小麦和玉米之间建立的多物种覆盖作物中利用霜冻引起的植物衰老。覆盖作物比对照积累了更多的氮。然而，由于低温导致覆盖作物衰老，部分终止的覆盖作物从 12 月到 2 月下旬显着增加了表土可用氮。尽管在我们的研究中没有观察到这种情况，但表土中的这种可用氮可能容易浸出。在冬季和晚春，覆盖作物对土壤水分没有显着的长期影响。以下玉米产量在对照和覆盖作物处理之间没有显着差异。在温带气候下无法可靠地终止对霜敏感的覆盖作物物种，但随着植物衰老，提供了持续的土壤可用氮供应。根据春季土壤湿度和天气条件，可能存在氮浸出风险，尽管可以通过种植早春作物来减轻这种风险。以下玉米产量在对照和覆盖作物处理之间没有显着差异。在温带气候下无法可靠地终止对霜敏感的覆盖作物物种，但随着植物衰老，提供了持续的土壤可用氮供应。根据春季土壤湿度和天气条件，可能存在氮浸出风险，尽管可以通过种植早春作物来减轻这种风险。以下玉米产量在对照和覆盖作物处理之间没有显着差异。在温带气候下无法可靠地终止对霜敏感的覆盖作物物种，但随着植物衰老，提供了持续的土壤可用氮供应。根据春季土壤湿度和天气条件，可能存在氮浸出风险，尽管可以通过种植早春作物来减轻这种风险。