高寒山区火烧土壤对其养分含量和酶活性的影响及灰色关联分析

EFFECT OF BURNING TURF ON NUTRIENT CONTENTS AND ENZYMATIC ACTIVITIES OF ALPINE MEADOW SOIL AND ITS GREY RELATIONSHIP ANALYSIS

本文研究结果表明，在高寒山区火烧土壤可加速有机质的分解，增加速效养分含量，因而使牧草产量大幅度提高。但3-4年后，因土壤速效养分含量明显减少，牧草产量又急剧下降。火烧对土壤酶破坏严重，火烧后3-4年，脲酶和蛋白酶活性可恢复到原来水平的50-80％，而碱性磷酸酶、过氧化氢酶和蔗糖酶活性可恢复到原水平的20-40％。但随着时间推移，土壤有机质积累和酶活性恢复有加速的倾向。在高寒山区，土壤酶活性与土壤有机质含量密切相关，与土壤速效养分含量和牧草产量无关，因而土壤有机质含量，土壤酶活性不能作为土壤肥力的标志。

The results showed that burning turf could accelerate the decomposition of organic matter,increase the available nuirient contents and raise grass output. But after 3-4 years of burning turf, the contents of available nutrients in the soil decreased obviously and the grass output dropped rapidly, Burning seriously destroyes the soil enzyme so that urease and protease achvities could be recovered to 50-80% of the original levels, but alkaline phosphatase, catalase and invertase to only 20-40% of the original levels. Accumulation of organic matter and the activities of soil enzymes tended to be enhaned as time went on. In alpine meadow soil the enzymahc activities were closely related to organic matter content but little related to soil available nutrient content and grass output. So the content of organic matter and the activities of soil enzymes could not be taken as the indexes of soil fertility.