Runoff loss of nitrogen and phosphorus from a rice paddy field in the east of China: Effects of long-term chemical N fertilizer and organic manure applications

• Published in: Global ecology and conservation Vol. 22; p. e01011
• Main Authors: Cui, Naxin, Cai, Min, Zhang, Xu, Abdelhafez, Ahmed A., Zhou, Li, Sun, Huifeng, Chen, Guifa, Zou, Guoyan, Zhou, Sheng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2020; Elsevier
• Subjects: Agricultural surface runoff; agrochemicals; China; ecology; eutrophication; fertilizer rates; nitrogen; Nitrogen and phosphorus loss; Nitrogen fertilizer; nitrogen fertilizers; Organic manure; paddies; phosphorus; rice; Rice paddy field; runoff; suburban areas; surface water; total nitrogen; urea; water pollution; China; Organic manure; Agricultural surface runoff; Rice paddy field; Nitrogen fertilizer; Nitrogen and phosphorus loss
• ISSN: 2351-9894; 2351-9894
• DOI: 10.1016/j.gecco.2020.e01011

Agrochemicals, e.g., nitrogen (N) and phosphorus (P) fertilizers are being used extensively to increase the agricultural production; however, considerable losses of these fertilizers find their way to the surrounding surface water bodies causing severe pollution and eutrophication. Such non-point source of pollution seemed to be more pronounced in the rice fields. Accordingly, a two-year (2018–2019) field study was conducted at a rice paddy field under long-term N fertilizer management practices in the rural suburb of Shanghai, China. N and P losses through the surface runoff in the paddy field were measured. Six N fertilizer practices were performed since 2011 as follows: no N treatment (N0), chemical N treatment (urea, N 46%) applied at the rates of 100 (N100), 200 (N200), 300 (N300) kg N ha−1 and combinations of chemical and organic N fertilizers (30% organic manure) at the rates of 200 (ON200) and 300 kg N ha−1 (ON300). Results showed that the highest runoff losses of TN (20.5 kg ha−1) and TP (1.66 kg ha−1) were respectively produced by N300 and ON300 practices during the rice growing season. TN runoff loss significantly decreased by reducing the rate of N fertilizer (P < 0.05). Comparing with N300 treatment, ON300, ON200 and N200 treatments reduced N loss by 2.4%, 27.0%, and 13.9% in 2018 and by 24.0%, 49.0% and 37.5% in 2019, respectively. Organic manure substitute decreased N loss but increased P loss from the surface runoff. The time period after fertilizer application significantly impacted N and P loss from surface runoff. The surface runoff occurring during the early stage after fertilizer applications contributed mostly to the total N loss. Consequently, the control of initial surface runoff events might be an effective strategy to attenuate the surrounding water pollution due to N surface runoff in the paddy fields. •Nitrogen (N) loss through surface runoff was decreased by reducing the rate of N fertilizer application.•Organic manure amendment decreased N loss but increased phosphorus (P) loss from the surface runoff.•The majority of N loss was NH4+-N in chemical N fertilizer treatments, while organic N was dominant in combined ones.•The time period after fertilizer application significantly impacted N and P loss from surface runoff.