Drip fertigation regimes for winter wheat in the North China Plain

Abstract

To establish the optimum fertilization rate and propose an appropriate drip fertigation regime for winter wheat in the North China Plain (NCP), a three-year field experiment was conducted to evaluate the effects of drip fertigation levels on soil available nutrients, winter wheat growth, grain yield, partial factor productivity (PFP), and irrigation water use efficiency (IWUE) during 2014-2017. The experiment investigated five fertilization rates: 20%, 45%, 70%, 95%, and 120% of the local recommended fertilizer dose (336 kg/ha N and 169 kg/ha P2O5) for high grain yield. The results showed that with the increase of fertilization rates, the concentrations of the soil available nitrogen (N) and phosphorus (P) in the 0–140 cm layer increased, and especially the N in deep layer (100–140 cm) and the P in surface layer (0–20 cm) increased evidently by 0.64 and 0.06 mg/kg with each unit increased of fertilization rate, respectively. Compared with the initial available nutrient concentrations, the fertilization rate of 45%–70% could basically maintain the balance of soil available N, and the fertilization rate of 70% provided a good balance for soil available P. Different fertilization rates had significant effects on winter wheat plant height (H), maximum leaf area index (LAI), dry matter (DM), grain yield, PFP, and IWUE. With each unit of increase in the fertilization rate, the winter wheat yield increased rapidly by 0.61% in the fertilization rate from 20%–70% and slowly by 0.32% in the fertilization rate from 70%–120%. The PFP decreased according to a power function with the increasing fertilization rate. Compared to the average grain yield and PFP under the local surface irrigation regime, drip fertigation of 70% of the local recommended fertilizer dose resulted in a yield increase of 4.0% and a PFP increase of 48.5%. To achieve a relatively high grain yield, high fertilization use efficiency, and minimize risk of environment pollution, a reduction in the fertilization rate to 70% of the local recommended fertilization dose (235 kg/ha N and 118 kg/ha P2O5) was suggested for winter wheat production under drip fertigation in the NCP.