Guan'gai paishui xuebao (Oct 2021)
Improving Nitrogen Use Efficiency and Growth of Paddy Rice Using Controlled Fertigation
Abstract
【Objective】 Nitrogen (N) loss from paddy fields is an environmental concern in rice production in the south of China. How to improve N use efficiency and alleviate its loss is an important issue in developing sustainable agriculture. The purpose of this paper is to investigate the feasibility of controlled fertigation to achieve this. 【Method】 The experiment was conducted in a paddy field and nitrogen fertilizer was applied at the panicle stage. We compared two fertilizations: conventional fertilization topdressing 367 kg/hm2 of N fertilizer, and reduced fertilization topdressing 267 kg/hm2 of N fertilizer (R). For each fertilization, the N fertilizer was either applied by hand-broadcasting (H), or through fertigation applied with irrigation. In each treatment, we measured N distribution in soil, rice growth and yield. 【Result】 ① Depending on N fertilization rate, the fertigation increased ammonium and nitrate contents in the soil by 27.4%~50.7% and 15.2%~33.3% respectively (p<0.05), and their distribution uniformity in the soil by 31.0% and 41.0%, respectively, compared with the hand-broadcasting application. ② On average, fertigation increased tiller numbers and rice height by 7.5% and 17.4% (p<0.05), rice yield by 16.4%, respectively, compared with the hand-broadcasting method. ③ Compared with topdressing only once, topdressing N twice could effectively increase the tillering by 8.5%~9.4%, rice height by 3.7%~4.0%, and ultimate yield by 6.3%~7.1%, while in the meantime maintaining ammonium content in the soil stable for a prolonged period. ④ Compared with the traditional irrigation and fertilization, fertigation combined with reducing fertilizer and more topdressing not only reduced N loss but also improved ammonium content and its distribution uniformity in the soil. 【Conclusions】 Fertigation can reduce N fertilizer application without compromising rice yield. It increased ammonium content in soil and improved rice growth and its ultimate yield; it can thus be used as an improved cultivation to increase N use efficiency and reduce its loss from soil.
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