不同种植密度对免耕山地油菜农艺性状和产量的影响

为在低纬高原山区综合评价并推广免耕山地油菜最优的种植密度，采用灰色关联度和模糊聚类等分析方法，对玉溪市2013—2015年4个不同海拔试点10个种植密度的免耕山地油菜农艺性状和产量进行对比分析。结果表明：（1）随着油菜种植密度的增加，倒伏指数增加，生育期、倒伏率、冻害率、冻害指数和白粉病发病率、病情指数有增加的趋势，而鸟害率和鸟害指数总体有下降的态势；（2）不同种植密度油菜的主要农艺性状有较大差异，单株有效角果数和单株生产力随着密度的增加而减少，而角粒数和千粒重则有不同程度的下降；（3）不同种植密度油菜产量与主要农艺因子的关联度差异较大；（4）不同种植密度间的产量存在不同程度的差异。推荐低纬高原山区免耕山地油菜最优种植密度为30万~36万株/hm2。

Influence of Planting Density on Agronomic Traits and Yield of No-till Mountain Rapeseed

The paper aims to explore the optimum planting density of rapeseed in no-till low latitude mountain areas. By using grey relation analysis and fuzzy cluster analysis, agronomic traits and yield of ten planting densities of rapeseed grown in no-till mountain areas with 4 different latitudes were compared in 2013-2015 in Yuxi. The results showed that: (1) with the increase of planting density, the lodging index rose, and the growth period, frozen percentage, frozen index, incidence of powdery mildew and disease index had an increasing trend, however, bird damage percentage and bird damage index appeared a decreasing trend; (2) the main agronomic traits were significantly different due to the difference of planting density, the number of effective pods per plant and productivity per plant decreased with the rise of planting density, seeds per pod and thousand-seed weight declined to different degrees as well; (3) there were varied associations between main agronomic traits and the planting density; (4) the yield under different planting densities varied a lot. The optimum planting density of 300-360 thousand plants per hectare is recommended for the low latitude no-till mountain areas.