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1984年,辽宁省各稻区的旱育苗都发生了不同程度的死苗现象。主要原因是,育苗期间出现低温天气,加之未掌握好旱育苗技术,使稻苗发生了立枯病。稻苗立枯病是水稻旱育苗最主要的病害,它分黄枯和青枯两种。黄枯病发生的主要原因是低温,在连续几大低温(5℃以下)、光照不足的环境条件下,如果苗床施氮肥较多、床土pH值在7以上,就容易发生黄枯病;青枯病发生的原因在于秧苗徒长,在施氮肥较多、床温过高、灌水较勤的情况下,秧苗生长嫩弱、细高、根系发育差,如遇暴热天气,地上部失水过多,根部吸水较慢,使秧苗体内水分失调,产生青枯病。
In 1984, drought nurseries in rice paddies in Liaoning Province all experienced different degrees of dead seedlings. The main reason is that during the emergence of cold weather nursery, combined with the lack of good drought nursery technology, so that rice seedling blight occurred. Rice seedling blight is the most important disease of rice drought nursery, it is divided into two kinds of dry yellowish green. The main reason for the occurrence of yellow leaf blight is low temperature. Under several environmental conditions, such as continuous low temperature (less than 5 ℃) and insufficient light, if the nitrogen fertilizer is more on the seedbed and the pH of bed soil is above 7, The root cause of bacterial wilt is the growth of seedlings. Under the condition of more nitrogen fertilizer, high bed temperature and more irrigation, the growth of seedling is tender and fine, and the root system is poorly developed. In case of hot storms, Too much, the root of water absorption is slower, the water imbalance in the seedling, resulting in bacterial wilt.