Estimation of Nitrogen Supply for Summer Maize Production through a Long-Term Field Trial in China

Supplying adequate nitrogen (N) to meet crop demand is critical for enhancing agricultural sustainability. Not only fertilizer N, but also N from other available sources should be considered in supply capacity. We conducted a 10-year farming experiment using split-plot design with two different main management approaches and three application strategies as add-on sub-treatments. Based on the experiment, we estimated total (TNsupply) summer maize cropping system, through considering environmental, soil, residue, sources. An appropriate TNsupply was established by correlating relative yield (RY), input output, use efficiency (NUE). The results revealed wide variation (from 88 755 kg ha−1). RY, input, output fitted well linear-plateau, linear, linear-plateau models, respectively. lower limits of achieving maximum RY were 361 358 ha−1, relationship between described linear-plateau. determined slope linear curve (55.4%) limit NUE, beyond which upper less than 497 ha−1. Thus, values ranged 325 ha−1 production, could ensure enough higher yields avoid excessive NUE environmental loss. Our findings highlight that can an alternative indicator evaluating management.