Soil nitrogen distribution and plant nitrogen utilization in direct-seeded rice with fertilizer deep placement
Deep placement controlled release N fertilizer increases N use efficiency but it is expensive.Few studies have examined the effects of conventional fertilizer deep placement.Therefore,a two-year field experiment with two N rates(120 and 195 kg N ha-1)and four N application treatments(D0,D50,D70,and D100 mean 0%,50%,70%,and 100%N was deep placed as basal fertilizer,respectively)was conducted to study the optimum ratio of basal deep placement to topdressing and its effect on soil N distribution and plant N utilization in direct-seeded rice.Basal N deep placement increased soil total N and available N concentrations.A significant difference in soil total N concentration between D100 and D0 was observed at 0,6,and 12 cm lateral distance away from deep placement line both at mid-tillering and heading.Despite D100 had the highest dry matter and N accumulation from seeding to mid-tillering,lack of N supply during the reproductive period resulted in obvious lower dry matter accumulation from heading to maturity,and the grain yield in D100 was lower than in D0,D50,and D70 by 11.6%,15.5%and 14.1%,respectively.Although topdressing was applied only one time as panicle fertilizer in D70,no significant difference was observed in N concentration in plant parts between D70 and D50 at heading,and in grain yield.N agronomic efficiency and N recovery efficiency in D70 was 2.4%and 3.3%higher than in D0,respectively.Considering the labor cost saved in D70,it was concluded that 70%N fertilizer deep placed as basal,and 30%as panicle fertilizer is a good approache to synchronously increase the grain yield and N use efficiency and save labor in direct-seeded rice.
direct-seeded distribution fertilizer deep placement nitrogen
Danying Wang Chunmei Xu Zaiman Wang Jinxiang Yan Song Chen Bhagirath Singh Chauhan Xiufu Zhang
The State Key Laboratory of Rice Biology,China National Rice Research Institute,Hangzhou 310006,Chin Key Laboratory of Key Technology on Agricultural Machine and Equipment,South China Agricultural Univ
国内会议
广州
英文
4-20
2016-11-28（万方平台首次上网日期，不代表论文的发表时间）