旱垂柳和垂柳黄化与土壤条件关系的研究

RESEARCH ON THE YELLOWS OF S. MATSUDANA AND S.BABYLONICA CAUSED BY DIFFERENT SOIL CONDITIONS

旱垂柳和垂柳既是优美的城市观赏绿化树种，又是用材林和防枋林的重要造林树种．这两个树种在哈尔滨市道里区苗圃和大庆等黑钙土上有程度不同的黄化现象．轻者．树叶自开放时便开始变黄、变白、变薄、叶片小．重者，叶子提早从植株上脱落、枯梢，至整个植株枯死．一般情况是绝大多数植株全株叶子变黄．这种黄化症影响了大酋的正常生长和苗木质量，给苗圃生产经营带来了一定的损失．生产部门提出了解释和解决这一问题的迫切要求．根据生产部门的要求，我们自１９８９年至１９９２年９月对这两个树种的黄化问题进行了系统的研究．通过研究，首先排除了是微生物引起的侵染性病害，而确定是由于不良的生态条件引起的．再通过深入的研究，确定是土壤的障碍性因素引起的．通过对黄化和正常植株下的土壤剖面形态观察和剖面各发生层土样的ＣａＣＯ３含量、盐酸反应、土壤ｐＨ值、土壤有机质、土壤的有效性铁、锰的测定；通过对黄化叶和正常叶的叶绿素含量、叶中全铁量的测定和对黄化植株施铁肥试验，测定了未施铁肥黄化叶和施铁肥黄化叶的叶绿素含量．研究得出的结论是：由于土壤中含有大量的ＣａＣＯ３和ＰＨＲ高，土壤呈碱性，致使土壤中缺少有效态铁，影响了根系对铁的吸收和铁在树体内的移动及有效性，不能?

S. babylonica and S. matsudana are not only fine ornamental trees in cities butalso important afforestation tree species of shelter forest and stand for timber.These two species have yellows of different extent in Chernozem of Harbinand Daqing. Leaves, at least. become yellow, white, thin, and small when openingup. At most serious condition, leaves drop off early; the top of a tree becomeswithered; whole tree becomes dead finally, Generally total leaves of most of theseedlings become yellow. The yellows influences normal growth of big seedlingsand seedling quality. so causes certain losses in nursery. Production departementputs forward pressing demand to solve the Problem.We studied the yellowing of S. babylonica and S. matsudana according toproductive need from 1989 to 1992. Through study we ruled out the cause ofinfected disease firstly and firmly believed that it was because of bad ecologicalcondition.Then through further research we found that the cause was soilobstruct.Through the measurement of the pattern of soil profile foue andCaCO3 content, Hcf reaction, PH, ofganic matter, effective Fe and Mn of soil ofdifferent layers, and through the measurement of chlorophyll content, total Fe-content of the yellowing and normal leaves and through the dressing of be to theyellowing seedings, we concluded finally that soil is short of effective Fe becauseo f a great quantity of CaCO3 and high soil PH, which affects Fe absorption ofroot system, Fe movement in tree and its effectiveness. Soil Fe can not meet theneed of normal growth of S. baby.lonica and S. matsudana, So they express oh1Qrosis.This study puts fortvard several suggests to provent chlorosis of S. babe.lonicaand S. matSUdana. This chill have important guidillg significance for production.