Recovery of mineral fertiliser N and slurry N in continuous silage maize using the 15N and difference methods

摘要: The stable isotope technique and the difference method are common approaches for estimating fertiliser N uptake efficiency. Both methods, however, have limitations their suitability may depend on management environmental conditions. A field experiment was conducted a humus sandy soil in northern Germany to estimate efficiency of silage maize year application (Zea mays L.) by as influenced type (mineral vs. cattle slurry), mode (separate or combined application), rate. Seven treatments were included (0, 50, 100 150 kg mineral ha−1; 20, 40 m³ slurry 50 ha−1 plus ha−1), where either labelled, split into two dressings. In addition, 4.1 labelled incorporated otherwise unlabelled ha−1, ha−1) from upper layer. Uptake 15N followed leaves, stalk, ear, whole crop. Fertiliser (FNUE15N) obtained ranged between 51 61%. Recovered mainly found while less remained leaves stalk. nitrogen rate tended increase amount recovered N, but effect not consistent among plant parts Plant non-fertiliser input up ha−1. Nitrogen recoveries dressings similar different well (FNUEdiff) estimated resulted substantially higher values compared FNUE15N, varying 56 98%. More taken layer with increasing supply, which is regarded major error source method. Slurry efficient than indicated recovery rates 21–22% 39–62% (FNUEdiff), respectively. When applied together, significantly lower efficiencies both single application, affected.