Estimating the capacity of cover crops (CC) to capture soil nitrogen (N) and to transfer captured N to subsequent crop remains a challenge because CC biomass production, N content and decomposition rate vary depending on environmental conditions and management practices. The objectives of this study were (1) to compare biomass production and N accumulation by a mixture of red and white clovers intercropped with barley, and oat, field pea and oilseed radish grown as catch crops after barley harvest, (2) to determine the capacity of different CCs to catch and transfer fertilizer N (mineral or pig slurry) to subsequent wheat and the soil reserve, and (3) to determine the influence of CC type on yield of spring wheat in the next year. A 2-y crop rotation (barley – wheat) was repeated twice on a sandy loam using ¹⁵N-labelled fertilizers applied at the time of CC establishment. Fertilization increased above-ground biomass yield in oat and oilseed radish, but had little effect on legume CCs. The legume CCs accumulated more total N in their biomass (63–127 kg N ha⁻¹) than non-legume CCs (47–68 kg N ha⁻¹). However, oat and oilseed radish were more efficient at capturing the applied fertilizer ¹⁵N (33–51 %) than legume CCs (2–36 %). Intercropped clovers resulted in the largest increases in subsequent wheat yields (23–92 %), followed by oilseed radish and field pea. At the end of the 2-y rotation (wheat harvest), the recovery of fertilizer ¹⁵N by subsequent wheat was < 10 %, whereas 26–60 % were still present in the 0−30 cm soil layer. We conclude that non-legume CCs have a good capacity to capture applied fertilizer N, whereas legume CCs (especially clovers) had a limited capacity. Nevertheless, clovers CC resulted in the greatest wheat yields in the following year, likely due to efficent transfer of symbiotically fixed N and improved soil quality, whereas fertilizer N captured by non-legume CCs was mainly routed to the soil N reserve, with potential to supply N to subsequent crops through a legacy effect.

估计覆盖作物（CC）捕获土壤氮（N）的能力以及将捕获的N转移至后续作物的能力仍然是一个挑战，因为CC生物量的生产，N含量和分解速率会根据环境条件和管理实践而变化。这项研究的目的是（1）比较大麦间种的红白三叶草和燕麦，豌豆和油菜萝卜作为大麦收成作物而种植的红色和白色三叶草的混合物，比较生物量的产生和氮的积累，（2）确定不同CC捕获和转移肥料N（矿物质或猪粪）到随后的小麦和土壤储备中的能力，以及（3）确定CC类型对明年春小麦产量的影响。在沙壤土上，每¹⁵年重复一次2y轮作（大麦–小麦），每次^15次建立CC时使用N标记的肥料。施肥增加了燕麦和油菜萝卜的地上生物量产量，但对豆类CC的影响很小。豆类CC在其生物量中累积的总氮（63–127 kg N ha ^-1）比非豆类CC（47–68 kg N ha ^-1）更多。但是，燕麦和油菜籽萝卜比豆类CC（2-36％）更能有效地捕获¹⁵ N（33-51％）的肥料。间作三叶草使随后的小麦单产增幅最大（23-92％），其次是油菜萝卜和豌豆。在2-y轮作结束（小麦收获）后，肥料¹⁵的回收随后小麦的氮含量<10％，而0-30厘米的土壤层中仍存在26-60％的氮。我们得出的结论是，非豆科植物CC具有很好的捕获施肥氮的能力，而豆科植物CC（尤其是三叶草）具有有限的能力。尽管如此，三叶草CC在第二年的小麦产量最高，这可能是由于共生固定氮的有效转移和土壤质量的改善，而非豆科植物CC捕获的肥料N主要运往土壤N储量，有可能通过遗留效应向后续农作物供应氮。