秸秆焚烧对不同耕层土壤酶活性、微生物数量以及土壤理化性状的影响

以秸秆焚烧后覆盖的耕层土壤为对象,研究秸秆焚烧对不同耕层土壤酶(过氧化氢酶,磷酸酶,脲酶和多酚氧化酶)活性、微生物数量的影响,并探讨土壤有机质含量、含水量、速效养分、微生物数量的增减程度与土壤酶活性增减程度的相关性。结果表明:过氧化氢酶、磷酸酶、脲酶和多酚氧化酶活性在焚烧秸秆后有不同程度的降低,其中耕层0-2cm,2-5cm土壤酶活性在焚烧前后都形成极显著性差异,5-13cm耕层的酶活性变化较小,13-20cm耕层的酶活性没变化。在微生物数量方面,焚烧秸秆导致0-2cm耕层的微生物数量大幅度减少,减少程度在80%左右,2-5cm耕层的微生物数量也有43%～52%的减少,5-13cm和13-20cm耕层的微生物数量没有变化。相关性分析表明,只有脲酶活性的降低程度与速效磷含量的增加程度达到显著相关,相关系数是0.959*。多酚氧化酶活性的降低程度与细菌、放线菌、真菌数量的降低程度均呈极显著相关性,相关系数分别是0.998**,0.999**,0.998**。同时脲酶活性的降低程度与细菌、放线菌、真菌数量的降低程度均呈显著相关性,相关系数分别是0.977*,0.974*,0.954*。

Effect of Straw Burning on Soil Enzyme Activity,Soil Microbial Quantity and Physical and Chemical Properties of Soil in Different Plough Layer

The topsoil which was covered with burned straw as the research object,this paper investigated effects of the different topsoil on the activities of catalase,phosphatase,urease and polyphenol oxidase,and soil microbial quantity.Meanwhile,this study discussed the relevance between the activities of enzyme and the content of soil organic matter,water content,available nutrient and microorganism quantity.The results showed that the activities of catalase,phosphatase,urease and polyphenol oxidase of topsoil which was covered with burned straw had been decreased,there were significantly difference soil enzyme activity changes before and after straw burning in the plough layer of 0-2 cm and 2-5 cm,small changes of the soil enzyme activity in the plough layer of 5-13 cm,there was no change of soil enzyme activity in the plough layer of 13-20 cm.The soil microbial quantity was greatly reduced in the plough layer of 0-2 cm because of straw burning,reduce degree at about 80%,there were different degrees of reduced from 43%~52% of the soil microbial quantity in the plough layer of 2-5 cm,the soil microbial quantity had not changed in the plough layer of 5-13 cm and 13-20 cm.The correlation analysis showed that: Only the decrease of urease activity and the increase of the content of available P reached significant correlation,correlation coefficient was 0.959*.Bacteria,fungi,actinomycete numbers of lower level and polyphenol oxidase activity degree of lower were into extremely significant correlation,correlation coefficient of respectively were 0.998**,0.999**,0.998**.Urease activity of lower level and bacteria,fungi,actinomycete numbers of lower level were into significant correlation,correlation coefficient of respectively were 0.977*,0.974*,0.954*.