title: Reducing N losses through surface runoff from rice-wheat rotation by improving fertilizer management.
abstract: To better understand N runoff losses from rice-wheat rotation and demonstrate the effectiveness of improved fertilizer management in reducing N runoff losses, a field study was conducted for three consecutive rice-wheat rotations. Nitrogen losses through surface runoff were measured for five treatments, including CK without N application, C200, C300 simulating the conventional practices, CO200, and CO300. Optimum N rate was applied for C200 and CO200, and 30% of chemical fertilizer was substituted with organic fertilizer for CO200 and CO300 with respect to C200 and C300, respectively. Rice season had higher runoff coefficients than wheat season. Approximately 52% of total N was lost as NH4+-N in rice season, ranging from 21 to 83%, and in wheat season, the proportion of NO3--N in total N averaged 53% with a variation from 38 to 67%. The N treatments lost less total N in rice season (1.67-10.7 kg N ha-1) than in wheat season (1.72-17.1 kg N ha-1). These suggested that a key to controlling N runoff losses from rice-wheat rotation was to limit NO3--N accumulation in wheat season. In both seasons, N runoff losses for C200 and CO300 were lower than those for C300. CO200 better cut N losses than C200 and CO300, with 64 and 57% less N in rice and wheat seasons than C300, respectively. Compared with the conventional practices, optimum N inputs integrated with co-application of organic and chemical fertilizers could reduce N runoff losses with a better N balance under rice-wheat rotation.
authors.affiliation: Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.
authors.forename: Yansheng
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.
authors.forename: Huifeng
authors.initials: H
authors.lastname: Sun
authors.affiliation: Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.
authors.forename: Zishi
authors.initials: Z
authors.lastname: Fu
authors.affiliation: Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.
authors.forename: Guifa
authors.initials: G
authors.lastname: Chen
authors.affiliation: Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China.
authors.forename: Guoyan
authors.initials: G
authors.lastname: Zou
authors.affiliation: Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China. zhous@outlook.com.
authors.forename: Sheng
authors.initials: S
authors.lastname: Zhou
mesh_terms: D000069599:Crop Production / Q000379:methods*; D005308:Fertilizers; D009584:Nitrogen; D012275:Oryza; D010758:Phosphorus; D012621:Seasons; D014908:Triticum; D014872:Water Movements; D014876:Water Pollution / Q000517:prevention & control*
chemical_list: D005308:Fertilizers; D010758:Phosphorus; D009584:Nitrogen
keywords: Improved fertilizer management; Nitrogen loss; Rice-wheat rotation; Surface runoff