土壤条件控制湿地松针叶病害的研究

近年威胁我国南方湿地松人工林的松针褐斑病、赤枯病近似于地方性病害,其发生及危害程度受土壤矿质养分条件所控制。湿地松的感病程度与土壤全钾含量是极显著的负相关,与土壤全氮含量、N/K、P/K和N/P比值均呈显著的正相关。 建立了适用于经研究过的丘陵山区的判别式。应用判别式可只根据土壤测定数据有效地判别或预测一定地区现有的或未来的湿地松林是否可能发病。Q型因子分析得出的林地聚类图进一步说明湿地松针叶病害种类及感病程度与土壤条件及有关的母质类型存在着相关性。在制定湿地松针叶病害防治方案或湿地松造林规划中,须有土壤—立地调查的可靠基础。

EFFECTS OF SOIL CONDITIONS ON CONTROLLIN THE NEEDLE DISEASES OF SLASH PINE

In recent years, some infectious diseases which caused fungi, i. e.,brown spot needle disease ( Lecanosticta acicola(Thum)Syd. ) and blight disease ( Pestalotia funera Desm ) have threatened rather seriously to the health and survival of young stands of slash pine ( Pinus elliottii Engelm ) in Southern China. These needle diseases, like endemic diseases, may be controlled by environmental factors, particulary the mineral nutritions of soils. According to the results of simple correlation analysis and two -diment-ion discriminate analysis, the genesis severity of the needle diseases have a significantly negative relation to the total potassium content and, a positive relation to the total nitrogen content, N/K, P/K and N/P ratio of soils. Applying discriminant function, we can predict the genesis of the diseases of slash pine on the bases of soil testing data in a given area. Q - type factor analysis outcome gives a diagram of the groups of classes of slash pine plantations and illustrates the correlations of the incidence of the diseases and soil conditions associated with parent materials types. Potassium chloride and farm manure have been proved available to reduce the needle diseaes. We should not ignore the Complication of environmental factors and their effects on the resistances of slash pine while we are making up a plan for controlling the diseases or introducing slash pine to a new area. The first thing is to make a good job of soil - site surveys.