Abstract The yields of crops in organic farming are typically lower than in conventional farming, although this depend greatly on local climatic conditions and on crop and soil management. A long-term study over three consecutive 4-year cropping cycles at three locations in Denmark compared organic arable cropping systems varying in fertilization management (green manure crops, cover crops, livestock manure) to study the long-term effects of soil fertility management on crop yields. The analysis of the results showed that the nitrogen (N) derived from cover crops has a legacy effect on the dry matter and N grain yield of spring barley being traceable 5-8 years back in time. The net N input of crop residues and manure for the crop cycles 1-4 and 5-8 years prior to the winter wheat had a significant effect on both the dry matter and N grain yield of wheat. The management of organic cropping systems should focus on reducing the weed pressure, promoting soil fertility and increasing the soil N supply to optimize crop yields. For both winter wheat and spring barley, the weed pressure reduced both crop dry matter and the N grain yield. A cover crop as pre-crop had a significant positive effect on both dry matter and N yield of spring barley, while a cover crop in the rotation did not significantly affect grain yield of winter wheat. For both winter wheat and spring barley, manure application was most effective in increasing crop yields. However, N in applied crop residues also had considerable yield-enhancing effects. For winter wheat, the N inputs from crop residues from previous crop rotation cycles (1-4 and 5-8 years) significantly increased yields, while for spring barley, N input in crop residues from incorporated cover crop and the long-term crop rotation cycle (5-8 years) significantly enhanced both dry matter and N grain yield. These legacy effects of soil fertility management through enhancing and retaining organic N inputs of organic arable cropping suggest that a holistic approach to soil and crop management is necessary, and this needs to focus on increasing weed suppression, soil fertility and targeting manure inputs for enhanced N uptake.

中文翻译：

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土壤肥力管理对有机耕作系统谷物干物质和氮粒产量的遗留影响

摘要 有机农业的作物产量通常低于传统农业，尽管这在很大程度上取决于当地的气候条件以及作物和土壤管理。在丹麦三个地点进行的连续三个 4 年种植周期的长期研究比较了不同施肥管理（绿肥作物、覆盖作物、牲畜粪便）的有机耕作系统，以研究土壤肥力管理对土壤肥力的长期影响农作物产量。结果分析表明，来自覆盖作物的氮（N）对春大麦的干物质和氮粒产量具有遗留效应，可以追溯到5-8年前。在冬小麦前 1-4 年和 5-8 年的作物周期中，作物残留物和粪便的净氮输入对小麦的干物质和氮粒产量都有显着影响。有机种植系统的管理应侧重于降低杂草压力、提高土壤肥力和增加土壤氮供应以优化作物产量。对于冬小麦和春大麦，杂草压力降低了作物干物质和氮粒产量。前作覆盖作物对春大麦的干物质和氮产量有显着的积极影响，而轮作覆盖作物对冬小麦的产量没有显着影响。对于冬小麦和春大麦，施肥对提高作物产量最为有效。然而，施用的作物残留物中的氮也具有显着的增产效果。对于冬小麦，来自先前轮作周期（1-4 年和 5-8 年）的作物残留物的氮输入显着提高了产量，而对于春大麦，来自结合覆盖作物和长期轮作的作物残留物中的氮输入周期（5-8 年）显着提高了干物质和 N 谷物产量。通过增加和保留有机耕作作物的有机氮输入，土壤肥力管理的这些遗留影响表明，土壤和作物管理的整体方法是必要的，这需要重点关注增加杂草抑制、土壤肥力和有针对性的粪肥输入，以增加氮摄取。来自结合覆盖作物和长期作物轮作周期（5-8 年）的作物残留物中的氮输入显着提高了干物质和 N 谷物产量。通过增加和保留有机耕作作物的有机氮输入，土壤肥力管理的这些遗留影响表明，土壤和作物管理的整体方法是必要的，这需要重点关注增加杂草抑制、土壤肥力和有针对性的粪肥输入，以增加氮摄取。来自结合覆盖作物和长期作物轮作周期（5-8 年）的作物残留物中的氮输入显着提高了干物质和 N 谷物产量。通过增加和保留有机耕作作物的有机氮输入，土壤肥力管理的这些遗留影响表明，土壤和作物管理的整体方法是必要的，这需要重点关注增加杂草抑制、土壤肥力和有针对性的粪肥输入，以增加氮摄取。