Cover crop nitrogen (N) cycling has an important role in agricultural production and contributes to peach [Prunus persica (L.) Batsch] N nutrition. This study evaluated black oat (Avena strigosa Schreb) and ryegrass (Lolium multiflorum L.) residue decomposition dynamics, N recovery from cover crop residues, and N compartmentalization in peach tree organs. A 2-year field trial was developed with labeled (3.6–4.0 atom% ¹⁵N excess) cover crop shoot biomass application in a 5-year-old peach orchard. The region’s climate is warm temperate (Cfb), and the soil is classified as a Typic Hapludalf. Litter bags with unlabeled shoot residues were also deposited in the orchard to assess biomass, carbon (C), N, lignin, cellulose, and non-structural biomass decomposition dynamics. After 13 months, the leaves, trunk, and roots showed the greatest proportion of N derived from residues (Ndfr) (35.4, 25.1, and 22.4%, respectively) while the greatest concentrations of ¹⁵N and Ndfr occurred in roots <2 mm (0.0376 and 0.94%, respectively). The N derived from cover crop shoots in the second production cycle was similar among tree organs. Ryegrass residues presented the highest decomposition constant (k) values for dry matter, total organic carbon (TOC), cellulose, and lignin. Hence, black oat residues presented a higher half-life (t^½) for dry matter, TOC, total N, cellulose, and lignin. The N derived from black oat and ryegrass residues in mature trees was expressively low (<1%) and similar between species. Within organs, the highest Ndfr occurred in peach leaves during the flowering stage, when the greatest residue decomposition rate also occurred. Soil N and plant internal N reserves are the major N sources for newly formed organs, but greater contributions to tree N nutrition may occur with long-term cover crop residue deposition and different plant species.

覆盖作物的氮素循环在农业生产中具有重要作用，并有助于桃子[ Prunus persica（L.）Batsch] N的营养。这项研究评估了黑燕麦（Avena strigosa Schreb）和黑麦草（黑麦草（Lolium multiflorum L.））残留分解动力学，从被覆作物残留物中回收N以及桃树器官中N的区室化。进行了为期2年的现场试验，其中标记了（3.6–4.0原子％¹⁵N过量）覆盖了5岁桃园中作物芽生物量的施用。该地区的气候为温暖带气候（Cfb），土壤被分类为Typic Hapludalf。带有未标记芽残留物的垃圾袋也沉积在果园中，以评估生物量，碳（C），N，木质素，纤维素和非结构生物量的分解动力学。13个月后，叶片，树干和根部显示出最大比例的来自残留物的氮（Ndfr）（分别为35.4、25.1和22.4％），而最大浓度为¹⁵N和Ndfr发生在<2 mm的根中（分别为0.0376和0.94％）。在第二个生产周期中，来自覆盖作物的新芽中的氮在树木器官之间相似。黑麦草残留物的干物质，总有机碳（TOC），纤维素和木质素的分解常数（k）最高。因此，黑燕麦残留物具有较高的半衰期（^t½）用于干物质，TOC，总氮，纤维素和木质素。在成熟树木中，源自黑燕麦和黑麦草残渣的氮含量极低（<1％），且在种间相似。在器官内，桃花期的Ndfr最高，而残留物的分解率也最高。土壤N和植物内部N储备是新形成器官的主要N来源，但是长期覆盖农作物残渣的沉积和不同植物物种可能会对树N营养产生更大的贡献。