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在早熟大白菜的栽培中,优良的早熟品种只有在适宜的时期进行播种,才可能获得较好的收成。目前生产上存在着盲目提早播种期,以图早种早收,但往往因病虫害发生严重而造成大幅度的减产甚至绝收,给早熟大白菜生产带来了不应有的损失。几年来的播期试验及生产实践证明,适期播种是早熟大白菜高产稳产的关键措施之一。一、大白菜对温度条件的要求栽培早熟大白菜所用的早熟品种生长期在70天以下。因为大白菜,既不耐酷暑也不抗严寒,生长期适宜的温度范围为5°—25℃,当温度超过25℃时生长不良,故应选择具有早熟和较好抗热性的品种。大白菜在各个生长时期对温度的要求不同。发芽期和幼苗期为20—25℃,莲座期为18—20℃,结球期为12—18℃。以发芽期和幼苗期对温度的要求较高。但要适期播种,过早幼苗期和莲座期的叶片徒长瘦弱,抗病力低下。因此,应根据幼苗期对较高温
In precocious cabbage cultivation, good precocious varieties can be harvested only when sown at the right time. At present there is a blind production of early sowing in order to plan early planting early, but often due to serious pests and diseases caused by a substantial cut or even yield, to precocious cabbage production has brought undue losses. Sowing date in recent years and production practice have proved that sowing is one of the key measures of high yield and stability of early maturity Chinese cabbage. First, the requirements of Chinese cabbage temperature conditions Cultivation of precocious cultivars of Chinese cabbage growing season in less than 70 days. Because cabbage, neither the heat nor the cold, the growth of the appropriate temperature range of 5 ° -25 ℃, when the temperature exceeds 25 ℃ poor growth, it should choose a precocious and better heat-resistant varieties. Chinese cabbage in different growth stages of the temperature requirements. The germination and seedling stage is 20-25 ℃, the rosette stage is 18-20 ℃ and the node is 12-18 ℃. To germination and seedling temperature on the higher requirements. However, sowing should be carried out on an appropriate schedule. Premature seedling stage and rosette leaves are long and thin, and their disease resistance is low. Therefore, it should be based on the seedling temperature to higher temperatures