一、弱苗弱苗一般表现为根少,蘖少,叶片窄小,叶色偏淡。弱苗冬前制造和储备养分不足,不利于安全越冬,返青后也难于健壮生长。弱苗成因,表现及措施。1.缩脖苗:干旱缺水形成。主要表现为:幼苗基部叶尖干黄,上部叶色灰绿,分蘖和次生根少或不能发生,植株生长缓慢,心叶迟迟不长呈现“缩脖”现象,严重时基部叶片枯黄干死,植株停止生长,这类弱苗多发生在抢墒播种、土壤干旱以及由于整地粗放、土壤过松、暗坷垃悬空而根与土壤不能紧密接触,吸水困难的麦田。管理此类苗要及早 First, the weak seedling weak seedlings are generally less performance, fewer tillers, leaves narrow, leaf color subdued. Weak seedlings before winter manufacturing and storage of nutrients is not conducive to the safety of winter, it is difficult to robust growth after turning green. Weak seedling causes, performance and measures. 1. shrink neck Miao: drought and water formation. Mainly as follows: the base of the seedling leaves yellowish yellow, the upper leaf color gray green, tillering and secondary root less or can not occur, plant growth is slow, the heart leaf late does not show “shrink neck ” phenomenon, severe yellow leaf base Dry dead, the plant stops growing, such weak seedlings occur in the grab moisture soil sowing, soil drought and due to extensive land preparation, the soil is too loose, unpredictable bumpy roots and the soil can not be in close contact with the water-difficult wheat fields. To manage such seedlings early