Deficit irrigation combined with reduced N-fertilizer rate can mitigate the high nitrous oxide emissions from Chinese drip-fertigated maize field

Abstract Agricultural soils are major sources of the greenhouse gas N2O, particularly under maize with high nitrogen (N) inputs and excessive irrigation. To determine how N and water management can mitigate N2O emissions from drip-irrigated maize fields, a field study was carried out in the North China Plain during the maize growing season. The objective of the study was to investigate the individual and combined effects of irrigation level and N input on N2O emissions and grain yields, as well as N and water use efficiency (WUE), under drip-fertigation management. The main treatments were two irrigation levels: 50 mm/event (sufficient irrigation, WH) and 25 mm/event (limited irrigation, WL), with four N application rates: 0 (N0), 90 (N1), 180 (N2), and 270 (N3) kg N ha−1. Pulses of N2O emissions were recorded every 2–3 d following each irrigation or fertigation (irrigation + fertilization) event. N input, irrigation, and their interactions all significantly influenced N2O emissions. A significant exponential relationship (P