Effect of orychophragmus violaceus incorporation on nitrogen uptake in succeeding maize

Abstract

Winter Orychophragmus violaceus (OV)/spring maize is a novel eco-agricultural system in North China Plain, but little is known about OV’s nitrogen (N) effects on succeeding maize growth and its contribution to maize N uptake and utilization during the growth. A pot experiment using 15 N was conducted, including five treatments: (1) Control – without OV incorporation and N fertilizer; (2) G – high 15 N labelled-OV incorporation; (3) 50%G – lower 15 N labelled-OV incorporation; (4) F – 15 N labelled urea fertilizer merely; (5) G + F – high OV incorporation combined with urea fertilizer. Increasing OV incorporation rate increased maize dry matter, yield, and total N uptake. Approximately 84–97% of the released OV’s nitrogen was absorbed before the V8 (the 8th leaf fully expanded) stage in G and 50%G treatments. However, only 19% of the released OV’s nitrogen was taken up at this period in G + F, and the rest was absorbed from V8 to maturity. G treated maize doubled the OV’s nitrogen uptake than the 50%G at maturity, and also had higher percentage contribution of OV’s N to total N accumulation. The G and 50%G maize obtained similar OV’s nitrogen use efficiency of 30%; however, this efficiency was further improved to 43% in the G + F. And more, G + F treatment further improved the maize yield by 9% compared to F treatments.