Effects of fertigation splits through center pivot on the nitrogen uptake, yield, and nitrogen use efficiency of winter wheat grown in the North China Plain

Abstract

The number of fertigation splits through center pivot irrigation system is a major concern for implementing sprinkler fertigation due to the possible losses caused by drift and volatilization. Field experiments were conducted at two sites of the semi-arid regions in the North China Plain with different soil fertilities to investigate the influence of the number of fertigation splits and the nitrogen applied on the nitrogen content, yield, and nitrogen use efficiency of winter wheat in the 2018 and 2019 seasons. In the experiments, one (N1), two (N2), and three fertigation splits (N3) in season based on soil Nmin-method was used. A treatment without in season fertilization (CK1) and a treatment with local fertilizer management method (CK2) were applied as control. Similar amounts of basal fertilizers and irrigation schedules were applied for all treatments. In the two-year study, both the nitrogen applied and sprinkler fertigation splits had significant influence on nitrogen content in winter wheat grain, and these effects varied with the changes of soil fertility. At the Beijing site of low soil fertility, the significantly great yield was obtained in the in-season N management treatments and the yield increased with the increasing of fertigation splits. The average yield in N3 treatment in both seasons was 32.5% and 15.1% higher than that in CK1 and CK2 treatments, respectively. At the Hebei site where inherent soil fertility was higher than that at the Beijing site, there was no significant differences in yield among all treatments, and the maximum yield within in-season N management treatments was obtained in N3 and N2 treatment in the 2018 and 2019 season, respectively. In both sites and seasons, the maximum partial factor productivity from applied N (PFPN) was obtained in CK1 treatment. The average PFPN in in-season N management treatments was 29.5% and 71.7% higher than that in CK2 treatment at the Beijing and Hebei site, respectively. More frequent fertigation was recommended for soils with low inherent fertility level.