Converting grassland to arable cropping leads to reduced soil organic carbon (SOC) stocks and thereby affects soil and climate protection goals. However, in forage production systems, silage maize produces considerable amounts of herbage and metabolizable energy yields for ruminants. To answer the question whether using direct drilling, as a minimal soil invasive technique, is able to prevent SOC stock degradation without loss of herbage yield in ley-arable systems, a two-year field experiment was set up on a sandy loam soil in northern Germany. In pre-management, a 10-year-old grassland sward was eradicated with a glyphosate and then sown with silage maize with (i) direct drilling (no-till, NT); and (ii) by conventional mouldboard ploughing (conventional tillage, CT). Each treatment included a non-N-fertilized (N0) and a 90 kg N ha⁻¹ year⁻¹ fertilized (N1) treatment. All silage maize treatments were analyzed in terms of above- (ANPP) and belowground net primary production (BNPP) and potential C input in comparison with the grassland control (GC) during the two years after conversion to arable silage maize. Quantification of SOC stocks and origin of C derived from residual plant material was estimated by the determination of natural ¹³C isotope abundance. Long-term impacts on SOC of a proposed ley-arable system (three years of grassland followed by three years of silage maize) using NT and CT practices were predicted using a soil C model. Results showed that ANPP and BNPP did not differ (p > 0.05) between tillage treatments and the two experimental years. Fertilization increased ANPP only in the second year with a lower fraction of roots belowground in comparison with N0 (p < 0.05). According to the ¹³C signature the total of silage maize-derived C after two years was up to 2.5–3.2 t C ha⁻¹ in both tillage treatments, of which ∼76% can be explained by the measured C inputs from plant residues. The NT treatment showed lower amounts of decay of previously sequestered C in the upper 10 cm during the two-year period after land use change to silage maize. However, long-term predictions revealed ongoing breakdown of soil C regardless of tillage management used for continuous silage maize after conversion from grassland. The insertion of a three-years grass phase followed by three years of silage maize established with NT techniques was able to maintain SOC stocks in the long-term.

将草地改种为可耕作作物会导致土壤有机碳（SOC）存量减少，从而影响土壤和气候保护目标。但是，在草料生产系统中，青贮玉米可以为反刍动物产生大量的牧草和可代谢的能量。为了回答使用直接钻探作为一种最小的土壤入侵技术是否能够在可耕种系统中防止SOC退化而又不损失牧草产量的问题，在北部的砂壤土上进行了为期两年的田间试验德国。在预管理中，用草甘膦根除10年的草地草皮，然后用青贮玉米播种（i）直接钻孔（免耕，NT）；（ii）通过传统的翻板犁（常规耕作，CT）进行。每种处理均包括非氮肥（N0）和90千克N ha^-1年^-1受精（N1）处理。在转换为可耕用青贮玉米之后的两年中，根据青贮玉米（ANPP）和地下净初级生产（BNPP）以及潜在的碳输入与草地对照（GC）进行了分析。通过确定天然¹³ C同位素丰度，可估算出SOC储量和源自残留植物材料的C的来源的数量。使用土壤C模型预测了使用NT和CT措施对拟议的可耕种系统（三年的草地，然后是青贮玉米的三年）对SOC的长期影响。结果表明，ANPP和BNPP没有差异（p> 0.05）之间的耕作处理和两个实验年。施肥仅在第二年才增加ANPP，与N0相比，地下根的比例更低（p <0.05）。根据¹³ C签名，两年后青贮玉米衍生的C总量高达2.5–3.2 t C ha ^-1在两种耕作处理中，其中约76％可以通过测量来自植物残留物的碳输入来解释。在土地利用改为青贮玉米后的两年内，NT处理显示在上部10 cm内隔离的C的衰减量较小。但是，长期的预测表明，无论从草地转化后用于连续青贮玉米的耕作管理如何，土壤C的持续分解。通过使用NT技术建立的三年青草玉米种植期和三年青贮玉米的种植，可以长期保持SOC的库存。