Effects of agronomic deep application and combined application of controlled release nitrogen fertilizer on rice yield and nitrogen loss in a paddy field

• Main Authors: ZHANG Fulin, LIU Dongbi, FAN Xianpeng, XIA Ying, ZHANG Zhiyi, CHENG Zizhen, WU Maoqian, GAO Hongbing, MAO Bo, KONG Xiangqiong
• Format: Article
• Language: zho
• Published: Agro-Environmental Protection Institute, Ministry of Agriculture 2021-09-01
• Series: Journal of Agricultural Resources and Environment
• Subjects: deep fertilization; controlled release nitrogen fertilizer; rice; nitrogen loss; yield
• Online Access: http://www.aed.org.cn/nyzyyhjxb/html/2021/5/20210516.htm

The study investigated the effect of agronomic deep placement of basal fertilizer(dry fertilization and wet mixing) and topdressings(fertilization before irrigation), combined with application of control released nitrogen(N) fertilizer on N loss and uptake. A plot experiment was conducted with four treatments:no N fertilization(N0), conventional N fertilization(Nc), agronomic deep fertilization (Nd), and agronomic deep fertilization combined with slow controlled release N fertilizer(reduced 10% N rate, Ns). The effects of agronomic deep fertilization of N and its combination with controlled release N were studied concerning the speciation and concentration of N in surface water, N loss from the paddy field, apparent N use efficiency, N surplus, soil available N content, and rice yield. Compared with conventional fertilization, the Nd and Ns treatments reduced the total nitrogen(TN) concentration in surface water of the paddy field in the high-risk period(within 7 days after basal fertilizer, within 5 days after tiller fertilizer, and within 4 days after panicle fertilizer) by 18.5% and 49.8%, respectively. These treatments also mainly decreased the total dissolved nitrogen, especially NH₄⁺-N. TN loss from paddy fields treated by Nd and Ns decreased by 19.1% and 47.6%, apparent N use efficiency increased by 15.3 and 3.9 percentage points, and N surplus decreased by 6.8% and 38.1%, respectively. The available N contents and rice yields showed increasing trends. The findings verified that agronomic deep placement of N can reduce N concentrations in surface water and N loss from paddy fields and can increase N use efficiency. The simple, green, and efficient fertilization technology is worthy of promotion. If combined with slow controlled release N fertilizer, the technology can further reduce N concentration in surface water and N loss from paddy field, as well as N fertilizer use rate.