西藏拉萨地区白菜型冬油莱栽培密度试验研究

群体密度对冬油菜壮苗和越冬有很大影响。密度太大，往往影响个体发育，形成弱苗，导致冬油菜越冬率降低；密度过小，虽有利于个体生长发育，但容易造成地力、光、热、水等自然资源浪费，同时容易造成苗势，营养体过大，形成旺苗，易受病虫害危害，反而不利于越冬。因此，合理的群体密度是提高壮苗率，保障冬油菜安全过冬的必要条件。通过研究表明，在西藏拉萨地区，当冬油菜密度在4—6万株/亩的情况，能得到较高产量。

The Density Experiment Research of Brassica winter oilseed rape cultivation in Lhasa area, Tibet

the Population Density strongly influence on strong sprout and wintering of winter oilseed rape. When the Density of winter oilseed rape is too often affect on growth, formation of weak seedling,resulting in reduced winter survival rate ; When the density is too small, although conducive to individual growing development, but likely to cause the waste of natural resources such as soil fertility, light, heat,water, and likely to cause seedlings potential, nutrition is too large, formation of flourishing seedlings, susceptible by pests and diseases, instead go against the overwintering. Thus, a reasonable populationdensity is the necessary condition for improve seedling rate and protection of overwintering. By studying, when winter oilseed rape＇ s density is between 40 - 60 thousand plants per mu, you can get a higher yield in Lhasa area, Tibet.