Nitrogen fertilizer reduction in combination with Azolla cover for reducing ammonia volatilization and improving nitrogen use efficiency of rice

PeerJ

article

Guoying Yang¹  Hongting Ji³  Hongjiang Liu¹  Yanfang Feng¹  Yuefang Zhang¹  Liugen Chen¹  Zhi Guo¹ 

[1] Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences;Key Laboratory for Crop and Animal Integrated Farming, Ministry of Agriculture;Nanjing Institute of Agricultural Sciences in Jiangsu Hilly Area, Jiangsu Academy of Agricultural Sciences

关键词: Nitrogen fertilizer reduction;    Azolla cover;    Ammonia volatilization;    Nitrogen use efficiency;    Rice;   

DOI  :  10.7717/peerj.11077

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

BackgroundExcessive nitrogen (N) application rate with low N use efficiency (NUE) caused a considerable amount of N losses, especially ammonia volatilization (AV). Proper N fertilizer reduction (RN) could significantly reduce AV. However, continuous RN led to a nutrient deficiency in the soil and therefore negatively impacted the NUE and rice yield. Paddy Azolla, a good green manure, is considered as a promising measure to decrease AV and improve NUE and grain yield of rice. However, there is limited information on the integrated effects of RN and Azolla cover on the AV, NUE, and rice yield, especially in the highly fertilized rice-growing systems.MethodsThe experiment was conducted including eight treatments: the control (without N fertilizer and Azolla cover), Azolla cover without N fertilizer (A), farmer’s N application rate (FN), FN + Azolla cover (FNA), 15% RN from FN (RN15), RN15 + Azolla cover (RN15A). 30% RN from FN (RN30), RN30 + Azolla cover (RN30A). The integrated effects of N fertilizer reduction and Azolla cover on AV, NUE, and rice grain was evaluated.ResultsRN15A and RN30A substantially reduced total AV by 50.3 and 66.9% compared with FN, respectively, primarily due to the lower surface water ammonia concentrations and pH. RN improved the efficiency of Azolla cover on reducing AV, with 4.1–9.9% higher than for FN. Compared with the FN, RN15A and RN30A enhanced apparent N recovery efficiency (ANRE) by 46.5 and 39.1%, which might be responsible for the lower NH3 emission and the increased total N uptake / total chemical N applied. Furthermore, RN15A and RN30A reduced yield-scaled volatilization by 52.3 and 64.3% than for FN, respectively. Thus, combining 15–30% RN with Azolla cover may be a way to reduce AV and improve ANRE without decreasing rice grain yield.

【 授权许可】

CC BY