楠竹枯黄(死)与土壤营养关系的研究(Ⅱ)

Study on the Relationship between the Withering of Phyllostachys pubescens and the Nutrition of Soil

通过不同受害程度竹林下土壤营养元素的测定 ,经横向对比并与《四川森林土壤》6 0年代长宁万岭箐竹区土壤状况记载的对比分析 ,结果表明 :虽然土壤 p H值变化不大 ,仅降低 0 .3～ 0 .4个 p H单位 ,但交换性酸总量显著增加 ,尤其是交换性铝 ,是原值的 3.6～ 7.5倍 ,交换性钙降低 ,盐基饱和度降低 ,致使 Ca/ Al比由原来的大于 1变为小于 1,重区与轻区相比 ,差异极显著 ,表明土壤存在着酸化的迹象。叶片及根系的测定结果进一步证实了土壤酸化引起的营养失调导致竹林生长不良 。

WT5BZ]Making a comparative analysis between the present and past status of the soil on Wanlingqing hills showed there was a tendency of soil acidation. Although small fluctuation in the PH happened,there was an obvious increase in the total amount of Ex (Exchangable) acid,especially Ex Al(Aluminium) which had risen to 3.6 7.5 times as much as the old value in 1960’s,while the Ex or Ca(calcium),the degree of base saturation and the ratio of Ca/Al from more than 1 in the past to less than 1 at present dropped obviously. The variance was evident between the soil indexes in severely damaged bamboo forests and those damaged slightly. The comparison between the severely damaged and the slightly damaged forests showed that the content of N,P,K,Ca,Mg in the leaves of the former was reduced,and the ratio of Ca/Al in the root was decreased,while the Al was elevated. These results indicated that soil acidation might lead to leaching of saline ions necessary for plant growth and accumulation of aluminum taxicant to the plants.