【摘要】 对退化高寒草原土壤酶活性研究的结果表明:1)相对于正常草地,轻度退化草地土壤纤维素酶、脲酶、碱性磷酸酶活性均呈不同程度的提高;中度退化草地土壤纤维素酶、碱性磷酸酶活性亦呈同一趋势,仅土壤脲酶活性显著降低;严重退化草地中3种土壤酶活性则均呈显著降低。2)不同土壤酶活性对土壤环境变化的敏感性总体呈碱性磷酸酶活性>脲酶活性>纤维素酶活性;土壤酶活性大小则均呈脲酶活性>碱性磷酸酶活性>纤维素酶活性。3)不同土壤酶活性与土壤有机碳均呈极显著正相关(r值为0.728 8~0.980 8,p≤0.01),与土壤全氮、有效氮、有效钾亦呈不同程度的正相关,与土壤有效磷含量则均呈显著或极显著负相关;土壤pH对土壤脲酶活性具有显著影响,对纤维素酶、碱性磷酸酶活性的影响则不甚明显。4)西藏高原高寒、干旱条件下,中度,特别是轻度退化草地一定程度的沙化所导致的土壤通透性能的显著改善对提高土壤酶活性,进而促进土壤有机残体的分解和有机质的形成具有重要作用。5)土壤酶活性不仅可以反映不同程度退化高寒草原土壤肥力水平的差异,同时亦可作为评价草地土壤肥力的一个基本指标。更多还原

【Abstract】 Soil enzyme activities in degraded alpine grassland were discussed in this paper.The results showed that:(1) compared with non-degraded grassland,the activities of soil celluase,urease and alkaline phosphatase in slight degraded grassland were all increased,and the similar trend was found in moderate degraded grassland except urease activity which was decreased;while the three kinds of soil enzyme activities were all decreased in serious degraded grassland.(2) In different kinds of soils,the sensitivity of the soil enzyme activities to soil environment change were generally in the order of alkaline phosphatase > urease > celluase;but all the soil enzyme activities ranked by the order of urease > alkaline phosphatase > celluase.(3) In different soils,we found significant positive correlation between soil enzyme activities and soil organic C(r=0.7288～0.9808,p≤0.01),and positive relationship between soil enzyme activities and soil total N,available N and available K,but negative correlation or significant negative correlation was found between soil enzyme activities and soil available P.The influence of soil pH on urease activity was obvious,but the influence on soil alkaline phosphatase and celluase activities was not obvious.(4) Under alpine and drought conditions in the Tibet Plateau,improved soil permeability,induced by moderate desertification in moderate or slight degraded grassland,played an important role in improving soil enzyme activities and further,accelerating the decomposition of soil organic matter as well as the forming of soil organic matter.(5) Soil enzyme activities could not only reflect the difference of soil fertility in different alpine degraded更多还原