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渭北旱塬地区油菜种植面积占全省40％左右,但亩产量长期徘徊在几十斤的水平,一个突出的原因是严重缺苗,每亩通常收不到一万株。造成缺苗的因素较为复杂,干旱、冻害、病虫害及栽培措施不当,是缺苗的主要原因。根据以往的研究,适期播种是控制油菜毒素病,培育适令壮苗,防止油菜越冬死苗的有效措施。但是,早塬地区播种期受降水早晚的制约,加之群众有“趁墒不等时”的历史习惯,所以,生产中往往偏早、
The planting area of rape in Weibei’s dry-land area accounts for about 40% of the province’s total. However, the output per mu has long been hovering at the level of a few pounds. One of the prominent causes is the serious shortage of seedlings, which usually can not receive 10,000 trees per mu. Lack of seedlings caused by the more complex factors, drought, frost damage, pests and diseases and inappropriate cultivation practices, is the main reason for lack of seedlings. According to previous studies, it is an effective measure to control sedge toxin disease, cultivate suitable strong seedlings and prevent overwintering seedlings. However, the sowing period in the early and middle reaches is limited by the precipitation in the morning and evening, and the masses have historical habits of “while taking advantage of the soil moisture.” Therefore, the production is often too early,