目前,春烟苗床期常发生‘五黄’的现象,严重影响烟苗正常生长。所谓‘五黄’即砂黄、水黄、肥黄、冻黄、热黄。‘砂黄’是由于播种时盖用的砂粒过细和过厚导致烟苗发黄。如果播种时注意用粗砂盖均匀(铜钱厚)即可防止。‘水黄’前期是因畦面不平,低温高湿引起烟苗发黄,后期是水多缺肥所致。防止办法是精细整 At present, the phenomenon of “five yellow” often occurs in the bed of spring tobacco seedbed, seriously affecting the normal growth of tobacco seedlings. The so-called ’five yellow’ that sand yellow, yellow water, fat yellow, yellow frozen, hot yellow. ’Sandy’ is due to yellowing of tobacco seedlings due to too thin and thick sand used in sowing. If you pay attention when planting with coarse sand cover (copper thick) can be prevented. ’Water yellow’ is due to the uneven surface, low temperature and humidity caused by tobacco seed yellow, late is due to lack of water. Prevention is fine whole