Effects of maize residue return rate on nitrogen transformations and gaseous losses in an arable soil

Over a growing season of maize, the NH3 volatilization loss rate from the full residue return treatment was 4.6%, which was significantly lower than that in the N fertilizer application only and half residue return plots (6.1%). Meanwhile, residue return rates showed a significant effect on annual N2O emissions from the maize system. Half residue return increased N2O emission (921.1 g N·ha−1), while full residue return marginally decreased N2O emissions (862.6 g N·ha−1) during the maize growing season, compared to the fertilizer-only treatment (881.2 g N·ha−1) (P <  0.05). In spite of the fact that N2O emissions in the non-growing season increased with the quantity of maize residue applied, the return of the full yield of maize residue to the soil could reduce both annual NH3 and annual N2O losses and increase soil total N and C storage after long-term use. It is suggested that residue application rate is a key factor when assessing residue benefits but the influence is in a nonlinear pattern. The combined application of full maize residue and synthetic N fertilizer is a promising N management strategy for mitigating gaseous N emissions.