生物质炭对旱作土壤生物性状及养分有效性的调控效应

通过盆栽试验研究了生物质炭施用对贵州中部地区旱作土壤微生物群落数量、酶活性和土壤养分有效性的影响。结果表明:对不同类型旱作土施用5%～15%(炭/土质量比)的生物质炭后,黄泥土、黄砂土中真菌、放线菌、细菌数量和硝化细菌、氨化细菌数量以及磷酸酶、过氧化氢酶、脲酶活性均表现出明显的增加,特别是黄砂土;而大泥土中放线菌、真菌数量和硝化细菌数量以及磷酸酶和过氧化氢酶活性出现较明显的提高,但氨化细菌数量及脲酶活性出现大幅度降低。此外,黄泥土、黄砂土施生物质炭后有效N、P、K、Ca、Mg、B含量表现出不同程度的增加,但土壤有效Fe、Mn、Cu、Zn含量则出现不同程度的下降;而大泥土中有效P、K、Fe、Mn、Cu、B的含量呈现不同程度的提高,但土壤有效N、Ca、Mg、Zn的含量出现不同程度的减少;其中这3类旱作土壤施炭后土壤有效Zn含量均表现出显著的下降。黄泥土、黄砂土及大泥土施用5%～15%的生物质炭后均能明显提高白菜及莴笋的产量,其中黄砂土施生物质炭的增产效果最好,其次是大泥土。不同类型旱作土壤施炭后土壤有效性养分数量变化存在较大的差别,施用生物质炭时要根据土壤特性配合使用一定比例的氮、磷、钾及适量的微量元素肥料,更有利于促进作物的生长。

Regulation Effects of Biochar on the Biological Characteristics and Nutrient Availability of Dryland Soils

The effects of biochar application on the microbial community, enzyme activity and soil nutrient availability in dryland soils of central Guizhou were studied through pot experiment. The results showed that after applying 5%~15% (biochar/soil mass ratio) biochar to different types of dryland soils, the number of fungi, actinomycetes, bacteria and nitrifying bacteria, ammoniated bacteria and the activity of phosphatase, catalase and urease in yellow soil and yellow sand soil increased obviously, especially in yellow sand soil. The number of actinomycetes, fungi and nitrifying bacteria in the lime soil, as well as the activity of phosphatase and catalase increased significantly, but the number of ammoniated bacteria and urease activity decreased significantly. In addition, the content of available N, P, K, Ca, Mg and B in yellow soil and yellow sand soil increased in different degrees, but the content of available Fe, Mn, Cu and Zn decreased in different degrees. The content of available P, K, Fe, Mn, Cu and B in the lime soil increased in different degrees, but the available N, Ca, Mg and Zn in the lime soil decreased in different degrees. The content of available Zn in these three dryland soils all decreased obviously after applying biochar. The application of 5%~15% biochar in yellow soil, yellow sand soil and lime soil could obviously increase the yield of cabbage and lettuce, of which the yellow sand soil applied with biochar was the best in increasing yield, followed by lime soil. There were significant differences in the changes of soil available nutrients among different types of dryland soils after applying biochar. When applying biochar, a certain proportion of nitrogen, phosphorus, potassium and appropriate amount of trace element fertilizers should be used according to soil characteristics, which could promote the growth of crops.