Soil gross mineral N production and consumption processes are crucial regulators of plant productivity and N loss from croplands. Substituting synthetic fertilizers by integrating legumes in cultivation systems is common in organic farming, but research on its long-term impact on dynamics of gross soil N transformation and associated environmental N loss is scarce. In particular, studies at a temporal resolution that allows for a mechanistic understanding of long-term effects of organic farming are missing. Therefore, we determined gross N turnover rates of ammonification, nitrification, and ammonium and nitrate immobilization at monthly temporal resolution during a full green rye-maize cropping sequence. Measurements were carried out at sites with same pedo-climatic background but organic farming (OF) and integrated farming (IF) history. During green rye growing, N turnover rates for OF and IF were low and not significantly different, likely owing to low temperatures. During silage maize growing, IF exhibited significantly higher average N turnover rates of 1.86, 4.46, and 5.57 mg N kg⁻¹ dry soil d⁻¹ for gross ammonification, ammonium immobilization, and nitrate immobilization, respectively, compared to OF values of 1.11, 1.80, and 2.90 mg N kg⁻¹ dry soil d⁻¹. The significantly higher N turnover rates were likely due to higher soil organic C, N and microbial biomass which result from different long-term management practices. Especially the increased immobilization potential on the IF site contributed to significantly lower area-scaled N₂O emissions (1.45 vs. 4.36 kg N ha⁻¹) during periods of high nitrification. This shows that for low SOC soils, integrated farming history with high C return enhances soil N cycling and reduces the risk of N losses in the form of N₂O emission.

土壤总矿物氮的生产和消耗过程是植物生产力和农田氮损失的重要调节因素。通过将豆类整合到栽培系统中来替代合成肥料在有机农业中很常见，但对其对土壤总氮转化动力学和相关环境氮损失的长期影响的研究很少。特别是，缺少允许对有机农业的长期影响进行机制理解的时间分辨率的研究。因此，我们确定了在完整的绿黑麦玉米种植序列中，以每月时间分辨率确定氨化、硝化以及铵态氮和硝酸盐固定化的总氮周转率。测量是在具有相同土壤气候背景但有机农业 （OF） 和综合农业 （IF） 历史的地点进行的。在绿黑麦生长过程中，OF 和 IF 的氮周转率很低，差异不显著，可能是由于低温。在青贮玉米生长过程中，与干土 d⁻¹ 的 OF 值 1.11、1.80 和 2.90 mg N kg⁻¹ 相比，IF 在总氨化、铵固定化和硝酸盐固定化方面的平均氮周转率分别为 1.86、4.46 和 5.57 mg N kg⁻¹ 干燥土壤 d⁻¹。氮周转率显著提高可能是由于土壤有机碳、氮和微生物生物量较高，这是由于不同的长期管理实践造成的。特别是，在高硝化期间，IF 站点固定化潜力的增加有助于显著降低区域尺度的 N₂O 排放（1.45 vs. 4.36 kg N ha⁻¹）。 这表明，对于低 SOC 土壤，具有高 C 回报的综合耕作历史增强了土壤氮循环，并降低了 N₂O 排放形式的 N 损失风险。