Nitrous oxide emission from winter wheat field as responded to irrigation scheduling and irrigation methods in the North China Plain

Abstract

Besides regulating soil water movements and nitrogen cycling, water management practices, such as irrigation schedule and irrigation methods, also affects possibly soil emission rates of nitrous oxide (N2O), an important greenhouse gas. The scale of irrigation scheduling and irrigation methods affecting N2O emission from winter wheat (Triticum aestivum L.) fields remains unclear. Hence, a field experiment with three irrigation schedule levels and three irrigation methods was conducted to estimate the N2O emission qualitatively from winter wheat fields by using static chamber method during April to May in 2017 and 2018 in the North China Plain (NCP). Three irrigation methods, i.e., sprinkler irrigation, surface drip irrigation, and flood irrigation were scheduled to irrigate the winter wheat immediately as the mean moisture of soil layer 0–100 cm depleted to 50%, 60% and 70% of the field capacity (FC). The research results show that both the irrigation schedule and irrigation methods influenced significantly (P < 0.05) N2O emissions, global warming potential of N2O emission (GWPN2O), grain yield, and water use efficiency (WUE). Surface drip irrigation at 60% FC, compared with sprinkler and flood irrigation at same schedule level, lowered substantially (P < 0.05) GWPN2O of 15–16% and 27–30%, improved grain yield of 5–8% and 6–7% and raised WUE of about 1–6% and 8–6% in 2017 and 2018 winter wheat season respectively. Relevant data also showed that the combination of surface drip irrigation and schedule level of 60% FC is reasonable to be recommended for winter wheat irrigation practice regarding better yield sustainability, higher WUE, and mitigating N2O emission in the NCP.