水氮供应对冬油菜氮素积累和产量的影响

Effects of Irrigation and Nitrogen Regimes on Seed Yield and Nitrogen Accumulation of Winter Oilseed Rape( Brassica napus L. )

通过2年桶栽试验,设置3个灌溉水平:低水(W0:(50%~60%)FC,FC为田间持水率,下同)、中水(W1:(60%~70%)FC)和高水(W2:(70%~80%)FC),3个施氮水平:不施氮(N0)、中氮(N1:施纯氮1.2 g/桶,约合180 kg/hm^2)和高氮(N2:施纯氮2.4 g/桶,约合360 kg/hm^2),研究不同灌溉和施氮水平对冬油菜生殖生长阶段地上部分生物量和氮素的积累、产量、耗水量和水分利用效率的影响。结果表明,中水中氮处理(W1N1)能显著增加冬油菜生殖生长阶段地上部分干物质量和氮素积累量,显著提高冬油菜的产量和水分利用效率;过量灌溉或施氮处理(W1N2、W2N1和W2N2)的促进作用不显著。2年W2N1处理的产量最高,平均为38.4 g/株;W1N1处理的水分利用效率最高,平均为1.07 kg/m3;但W2N1和W1N1处理的产量和水分利用效率不存在显著差异,而W1N1处理的耗水量显著小于W2N1处理。另外,冬油菜的籽粒产量和水分利用效率与耗水量均呈显著的二次抛物线关系,冬油菜的水分-产量响应系数为1.36。全面考虑产量与节水节肥等因素,W1N1处理为该研究区较优的冬油菜灌水施氮策略。

In order to investigate the optimal scheme of irrigation and nitrogen application for winter oilseed rape（ Brassica napus L.）,two-year（ 2013—2014 and 2014—2015） barrel experiments were conducted to evaluate the effects of different irrigation and nitrogen applications on aboveground dry matter and nitrogen accumulation during reproductive growth stage,seed yield,evapotranspiration（ ET）and water use efficiency（ WUE）,and then determine the yield response factor（ Ky） of winter oilseed rape. The experiments included three irrigation levels（ W0：（ 50% ~ 60%） FC,FC denoted field capacity; W1：（ 60% ~ 70%） FC; W2：（ 70% ~ 80%） FC） and three nitrogen levels（ N0： 0 g; N1：1. 2 g; N2： 2. 4 g）. The results showed that W1N1 could obviously improve aboveground dry matter and nitrogen accumulation during reproductive growth phase,seed yield,and WUE of winter oilseed rape.However,excessive irrigation or nitrogen（ W1N2,W2N1 and W2N2） would not significant increase the aboveground dry matter and nitrogen accumulation,seed yield,and WUE in comparison with W1N1.W2N1 achieved the highest seed yield across the two years,while W1N1 obtained the highest WUE.Though no significant differences of seed yield and WUE were found between W1N1 and W2N1,the ET in W1N1 was significantly lower than that in W2N1. In addition,seed yield and WUE were all showed a significant quadratic parabola relationship with ET,and the Kyof winter oilseed rape was 1. 36. In comprehensive consideration of seed yield, water and fertilizer conservation, W1N1 treatment was recommended as an appropriate irrigation and nitrogen application schedule for winter oilseed rape in the study area.