麦-豆轮作体系周年施氮量对夏大豆氮素利用效率和产量的影响

Effect of annual nitrogen application rate on nitrogen use efficiency and yield of summer soybean in winter wheat-summer soybean rotation system

【目的】探明伊犁河谷麦?豆轮作体系下施氮对夏大豆氮素利用及产量的影响,筛选出夏大豆高产的周年施氮组合。【方法】于2016—2018年在新疆伊宁县进行小麦?大豆轮作田间试验。前茬冬小麦设4个施氮水平,分别为0、104、173、242 kg/hm^2,即WN0、WN1、WN2、WN3处理;在小麦各处理基础上,再设夏大豆3个施氮水平,分别为0、69、138 kg/hm^2,即SN0、SN1、SN2处理。从大豆出苗后20天起,每10天取一次植株样,测定不同部位的氮素含量和生物量,收获期测产量及其构成,计算夏大豆的氮素利用效率。【结果】前茬麦季及大豆当季施氮量均显著影响夏大豆干物质及植株氮素积累量。在麦季施氮0~173 kg/hm^2范围内,夏大豆当季施氮有利于增加植株干物质积累量及各器官氮素积累量,且小麦季施氮水平越低,夏大豆当季施氮对干物质积累及植株氮素积累的作用越显著。在麦季施氮量为173 kg/hm^2时,夏大豆季施氮可增加产量,且以SN1处理产量最高;而当小麦季施氮量为104和242 kg/hm^2时,夏大豆季SN1和SN2处理产量之间没有显著差异。在前茬小麦季施氮的基础上,夏大豆当季氮肥吸收利用率、农学利用率及偏生产力均随当季施氮量的增加而降低。【结论】在伊犁河谷冬小麦?夏大豆轮作体系下,前茬麦季施氮173 kg/hm^2基础上,夏大豆当季施氮69 kg/hm^2可获得较为理想的夏大豆产量和氮素利用效率。

【Objectives】The optimum annual nitrogen(N)application rate in the summer soybean system was studied in order to achieve high N use efficiency and yield of wheat-soybean rotation system in Ili valley.【Methods】A field experiment was conducted in Yining County,Xinjiang Uygur Autonomous Region from 2016 to 2018.The N rates in previous wheat season were 0,104,173 and 242 kg/hm^2,recorded as WN0,WN1,WN2 and WN3 in turn;On each wheat N rate treatment,three N rates for the following summer soybean were setup as 0,69,138 kg/hm^2,and recorded as SN0,SN1 and SN2 in turn.Since the 20th day after germinating,soybean plant samples were collected every 10 days for the measurement of dry matter weight and N content.At harvest,the yield and yield components were investigated,and the nitrogen use efficiencies were calculated.【Results】N application rate in the previous wheat season significantly affected the dry matter and N accumulation of summer soybean.When the N rate in wheat was in range of 0 to 173 kg/hm^2,applying N in summer soybean could increase the dry matter accumulation and plant N uptake,and the lower N rate in wheat caused better effect of N application in soybean.When the N rate in wheat season was 173 kg/hm^2,nitrogen application in soybean season increased yield,and the yield of SN1 treatment was the highest;when the N rates in wheat season were 104 and 242 kg/hm^2,those between SN1 and SN2 were not significantly different.The nitrogen recovery rate,the agronomy utilization efficiency and partial productivity of nitrogen fertilizer in summer soybean decreased with the increase of nitrogen application rate.【Conclusions】In the winter wheat-summer soybean rotation system in Ili Valley,when the N application rate in pre-wheat season is 173 kg/hm^2,the suitable nitrogen rate in the following soybean season is 69 kg/hm^2,which could meet the nitrogen requirement in all the growing stages and the high yield formation,and the nitrogen use efficiency of summer soybean.