不同施氮条件下稻茬直播油菜氮素吸收和利用对产量形成的影响

试验以扬油6号为材料,设置不同施氮水平,通过测定初花期和成熟期各器官干重和氮素含量,研究了不同施氮条件下稻茬直播油菜氮素吸收和利用对产量形成的影响。结果表明:(1)氮素利用率随氮素吸收量的增加呈先上升后下降的趋势。(2)氮素吸收量与初花期、成熟期生物产量以及花后干物质积累量都呈极显著正相关,氮素利用率则相反,但未达显著水平。(3)氮素吸收量与角果数和总粒数呈极显著正相关,而氮素利用效率与各产量构成因素均相关不显著。(4)籽粒产量随氮素吸收量的增加而显著增加,而随氮素利用率的提高呈下降趋势,但相关不显著。(5)增加氮素吸收量对提高产量的直接作用最大,增加花后干物质积累量和增加库容量也都是通过增加油菜对氮素的吸收量而提高产量;提高氮素利用率对提高产量也有一定的正效应,但其负效应更大。

Effects of nitrogen absorption and utilization on yield formation of direct-sowing rapeseed in paddy rice field under different nitrogen application levels

Test to Yangyou No.6 as material,the effects of nitrogen absorption and utilization on yield formation of direct-sowing rapeseed in paddy rice field under different nitrogen application levels were studied through measuring dry matter weight and nitrogen content in various organ at beginning flower and maturity stage.The main results were as follows:(1) Nitrogen utilization efficiency increased first and then decreased with the increasing of nitrogen absorption amount.(2) Biomass at flowering and maturing stage and biomass accumulated after flowering were all positive correlated to nitrogen absorption amount significantly,while nitrogen utilization efficiency was the opposite,but did not reach the significant level.(3) Pod number and total seed number were extremely significant positive with nitrogen absorption amount,but nitrogen utilization efficiency were not significant correlated with yield components.(4) Seed yield increased significantly as the increasing of nitrogen absorption amount,but showed a downward trend as the increasing of nitrogen utilization efficiency.(5) The effect of increasing nitrogen absorption amount on increasing seed yield was the largest.The effect of increasing biomass accumulated after flowering and storage capacity on increasing seed yield was also through increasing nitrogen absorption amount.The positive effect of increasing nitrogen utilization efficiency on increasing seed yield was smaller than negative effect.