江河源区不同建植年限人工草地土壤微生物及酶活性研究

Studies of Soil Microorganisms and Enzyme Activities on Artificial Grassland with Different Cultivation Years in Headwater Area of Yangtze and Yellow Rivers

对江河源区不同建植年限人工草地(2龄、4龄、6龄)土壤养分、微生物数量及酶活性进行研究。结果表明:不同建植年限人工草地土壤养分随着建植年限的增加呈"V"型规律变化,其中人工2龄草地土壤养分含量最高,6龄草地土壤养分含量虽不及2龄草地高,但均明显高于4龄草地。土壤细菌和放线菌数量与土壤养分变化规律一致,真菌数量随建植年限的增加呈降低趋势,土壤脲酶、过氧化氢酶和中性磷酸酶活性与细菌、放线菌和土壤养分变化规律相同。同时,土壤养分、微生物数量和酶活性变化均具有明显的空间层次现象,即随土层的加深呈降低的趋势。经典型相关分析表明,土壤细菌与土壤有机质、全氮、速效钾和pH值之间相关性最好,脲酶和过氧化氢酶活性与土壤有机质、全氮、速效氮、速效钾和pH值之间相关性最好,故土壤微生物数量和酶活性可作为评价土壤肥力的指标。

The soil nutrients,microorganism quantity and enzyme activity are studied and analyzed in artificial grassland with different cultivation years in the headwater area of Yangtze and yellow rivers.The results are as follows: soil nutrients of artificial grassland decreased and then increased regularly with change of the cultivation years.The soil nutrient content of two aged artificial grassland was highest,and the six aged grassland lower than two aged,and both of them were significantly higher than the four aged.The changes of soil bacterium and actinomycetes were consistent with the soil nutrients.Similarly,the soil urease,catalase and neutral phosphatase activities have equal regularities. The quantities of fungi descended with the increase of cultivation years.Meanwhile,the soil nutrients,microbial quantities and enzyme activities decreased with the increase of soil depth.The canonical correlation analysis showed that soil bacterium had the best correlation with soil organic matter,total nitrogen, effective K and pH value;soil urease and catalase activities had the best correlation with soil organic matter,total nitrogen,effective nitrogen,effective K and pH value.So the soil microorganism and enzymes can be used as evaluation index of soil fertility.