绿洲灌区春小麦产量和氮素利用率对绿肥还田量的响应

[目的]西北绿洲灌区小麦多连作种植,存在氮肥投入量大、利用率低等问题.研究麦后复种绿肥对小麦产量和氮素利用的影响,以期为该区小麦氮素高效利用技术的构建提供理论依据.[方法]2018—2020年,在河西绿洲灌区开展小麦复种绿肥田间试验,春小麦季设置不施氮肥(N0)和传统施氮量180 kg/hm2(N1)处理,小麦收获后分...

Response of grain yield and nitrogen utilization efficiency of spring wheat to green manure incorporation amount in oasis irrigation district

  【Objectives】   Continuous cultivation of spring wheat causes excessive N fertilizer input and reduction in N fertilizer utilization efficiency in Hexi Oasis Irrigation Region. Green manure ( Vicia villosa Roth) could be incorporated into soil after wheat harvest to achieve a high-efficient N management system but the optimal amount of green manure incorporation is not known and requires investigation.   【Methods】   A field experiment was conducted from 2018 to 2020. The spring wheat was first cultivated with N 180 kg/hm2 (N₁) and without N application (N₀). After the wheat harvest, green manure (Vicia villosa Roth) was incorporated into field at different rates i.e., no green manure (G₀, control), incorporation of 15000 kg/hm2 (G₁), 30000 kg/hm2 (G₂), and 45000 kg/hm2 (G₃) green manure to the field at full blooming stage. N uptake, grain yield and N use efficiency of the wheat cultivated after green manure application were investigated.   【Results】   Green manure incorporation significantly increased aboveground N accumulation of spring wheat. Compared to N₁G_0, N accumulation of wheat in N₁G₁, N₁G₂, and N₁G₃ treatments increased by 8.7%?9.3%, 15.3%?16.6%, 11.9%?12.3%. Compared to N₀G₀, N accumulation of wheat in N₀G₁, N₀G₂, and N₀G₃ increased by 3.3%?4.0%, 4.6%?5.6%, 5.9%?8.4%. In the two years, N rate, green manure returning amount and their interaction effects significantly affected the translocation amount, translocation rate and contribution of nitrogen from leaves and stems to panicles. Among all green manure treatments, N₁G₂ treatment had the highest translocation and contribution value. Compared with N₁G₀, the N transfer amount of leaf-ear and stem-ear increased by 38.8%?49.5% and 49.1%?64.7%, the corresponding N transfer rate increased by 8.0%?21.5% and 13.0%?14.9%, and the contribution rate to grain increased by 11.0%?26.0% and 25.6%?31.3%, respectively. N₁G₂ treatment had the highest grain yield, N harvest index and N use efficiency. The fitting equation revealed that optimal nitrogen use efficiency could be obtained by incorporating green manure amount of 30000 kg/hm2 into the field.   【Conclusions】   In arid oasis irrigation area, incorporation of green manure at the rate of 30000 kg/hm2 combined with 180 kg/hm2 N application can be used as an efficient management technique for increasing grain yield and N use efficiency of spring wheat.