Zeolite amendment coupled with alternate wetting and drying to reduce nitrogen loss and enhance rice production

Abstract Clinoptilolite zeolite (Z) has been increasingly recognized as a valuable soil conditioner, which is beneficial to nitrogen (N) loss reduction and crop yield improvement. However, limited information is available for a rice production system, especially under alternate wetting and drying irrigation (AWD). Therefore, a 2-year field experiment with lysimeter was carried out in a split plot design with two irrigation regimes (CF: continuously flooded irrigation, AWD: alternate wetting and drying irrigation) as main plots and three Z amendment rates (0, 5 and 10 t Z ha −1 ) as sub-plots. The impact of Z amendment on ammonia (NH 3 ) volatilization, N leaching, rice grain yield, water productivity (WP) and economic benefit were analyzed under both irrigation regimes. The results showed that AWD slightly reduced NH 3 volatilization without Z application, but significantly increased residual mineral N (RMN) in soil at the depths of 0 − 30 and 30 − 60 cm, and NH 4 + -N and NO 3 − -N leaching, relative to CF. AWD-grown rice significantly improved WP without affecting grain yield in 2016, but reduced yield in 2017 without Z amendment. Compared with control (without Z amendment), addition of 5 and 10 t Z ha -1 increased RMN by 12 and 21%, respectively in the 0 − 30 cm soil depth, but reduced it by 18 and 32%, respectively in the 30 − 60 cm soil depth. Total NH 3 volatilization and NH 4 + -N and NO 3 − -N leaching loss decreased with increasing rates of Z amendment. Z amendment significantly increased N uptake, rice grain yield, economic benefit and WP, especially under AWD. In the two years, integration of 10 t Z ha -1 with either AWD or CF management reduced NH 3 volatilization without increasing N leaching and increased rice grain yield and WP, with an increased economic benefit of $126 − 195 ha -1 , as compared to conventional management (CF without Z). The use of zeolite merits further investigation for application in the rice production systems.