Greenhouse gas emissions and ammonia loss of maize fertigation with a centre pivot system in the North China Plain

Abstract Whether sprinkler fertigation stimulates greenhouse gas emissions and ammonia loss is an indispensable consideration for nitrogen management. To assess the effect of sprinkler fertigation on N 2 O, CH 4 , CO 2 and NH 3 emissions, three N recommendation methods for summer maize, including the local empirical value, mineral nitrogen method and modified mineral nitrogen method, and three topdressing methods, including no topdressing, one topdressing and two topdressings following intermittent rainfall events, were tested in the 2020 and 2021 seasons. Surface irrigation with fertilizer broadcasting was used as the control treatment. The results indicated that nitrogen topdressing and rainfall promoted soil N 2 O, CO 2 and NH 3 emissions but had no obvious effect on CH 4 emissions. The increasing nitrogen application rate increased gaseous nitrogen losses of N 2 O and NH 3 . Sprinkler fertigation with the modified mineral nitrogen method and two topdressings obtained the greatest yield and nitrogen use efficiency. Compared to the control treatment, the yield and nitrogen use efficiency in the sprinkler fertigation treatments was maximally increased by 20%, and the cumulative NH 3 volatilization losses and gaseous nitrogen loss rate were both reduced by 16%, while the cumulative N 2 O emissions increased by 4%. No significant difference in global warming potential was obtained among all treatments.