Dicyandiamide application improved nitrogen use efficiency and decreased nitrogen losses in wheat-maize crop rotation in Loess Plateau

摘要

Inhibition of nitrification as a mitigation tool to abate nitrogen (N) losses and improve N use efficiency (NUE) is a promising technology. Nitrification inhibitor (dicyandiamide, DCD) was evaluated in two consecutive wheat-maize rotations (2015-2017), with two different N fertilizer levels applied in wheat (160, 220 kg N ha(-1)) and maize (180, 280 kg N ha(-1)). More NH4+-N contents (101% and 102% in wheat and 74% and 73% in maize) and less NO3--N contents (37% and 43% in wheat and 46% and 57% in maize) were observed at both N levels treated with DCD compared to without DCD. Higher pH, lower EC and reduced NO3--N accumulation were the other benefits of DCD. The NO3--N accumulation within the 0-200 cm soil profile was significantly less at both N levels with DCD (66 mg kg(-1) and 121 mg kg(-1)) compared to without DCD (96 mg kg(-1) and 169 mg kg(-1)). Application of DCD also improved the growth and yield in both crops. Increase in NUE from 38% to 49% in wheat and 27% to 33% in maize with DCD at higher N level was also observed. Overall, the effectiveness of DCD in retarding the nitrification process was higher in wheat than maize.