Natural 15N Abundance in Winter Wheat Amended with Urea and Compost: A Long-Term Experiment

We investigated 15N abundance (δ15N) of winter wheat (Triticum aestivum cv. Jinmai 1) plants and soil at different growth stages in a field with a 13-year fertilization history of urea and compost, to determine whether or not the δ15N of plant parts can be used as an indicator of organic amendment with compost. Plant parts (roots, leaves, stems and grains) and soil were sampled at re-greening, jointing, grain filling and mature growth stages of winter wheat. There were significant differences between the urea and compost treatments in δ15N of whole plants, plant parts and soil over the whole growing season. Determination of the δ15N of plant parts was more convenient than that of whole plant to distinguish between the application of organic amendment and synthetic N fertilizer.