The effects of differentiated water supply after anthesis and nitrogen fertilization on δ15N of wheat grain

The δ15N signature of plants integrates various processes in soil and plant. In this study, the effect of different water regimes applied during the period of grain growth of winter wheat on grain δ15N was examined in a 4‐year field experiment. The treatments comprised water shortage (S), an ample water supply (W), and rain‐fed crop (R). Zero fertilization (N0) and 200 kg N.ha−1 in mineral fertilizer (N1) treatments were studied. The grain 15N was determined during grain growth and at maturity. The water regime, nitrogen application and year had a significant effect on mature grain δ15N (p