Influences of irrigation and fertilization on soil N cycle and losses from wheat–maize cropping system in northern China

Abstract Excess of water irrigation and fertilizer consumption by crops has resulted in high soil nitrogen (N) losses and underground water contamination not only in China but worldwide. This study explored the effects of soil N input, soil N output, as well as the effect of different irrigation and N- fertilizer managements on residual N. For this, two consecutive years of winter wheat (Triticum aestivum L.) –summer maize (Zea mays L.) rotation was conducted with: N applied at 0 kg N ha−1 yr−1, 420 kg N ha−1 yr−1 and 600 kg N ha−1 yr−1 under fertigation (DN0, DN420, DN600), and N applied at 0 kg N ha−1 yr−1 and 600 kg N ha−1 yr−1 under flood irrigation (FN0, FN600). The results demonstrated that low irrigation water consumption resulted in a 57.2% lower of irrigation-N input (p