不同碳源物质对土壤无机氮生物固定的影响

采用培养试验方法 ,研究了不同碳氮比值的碳源物质对土壤无机氮生物固定的影响及其在土壤氮素调控中的作用。结果表明 :①单独施用碳氮比较高的麦秸、玉米秸和豆秸时 ,土壤微生物的固氮能力明显降低 ,高碳氮比的麦秸并没有表现出对土壤无机氮强烈固定的优势 ,而碳氮比较低的鸡粪对土壤无机氮没有固定作用 ;②当碳氮比较高的麦秸、玉米秸及豆秸与化肥配合施用时 ,土壤微生物的固氮能力明显增强 ,与单施化肥相比 ,麦秸、玉米秸和豆秸配施化肥 ,对肥料氮的最大固定率分别提高 2 5 31 %、 1 2 46%和 1 0 64%;③土壤微生物对土壤无机氮的生物固定有重要的“保肥”和“稳肥”机能。

Effects of Different Organic Substance on Biological Nitrogen Fixation in Soil

The pot incubation experiment was conducted to study the influence of different C/N organic substance on the biological fixation of inorganic nitrogen and its effect in the regulation of nitrogen in soil. The results showed that firstly, with the application of higher C/N organic substances (such as wheat straw, corn straw and legume straw) to soil separately, the capacity of biological nitrogen fixation in soil decreased evidently and there was no advantage over wheat straw.There was no effect on biological fixation of inorganic nitrogen in soil when lower C/N chicken manure was applied to soil. Secondly, when higher C/N organic substance and fertilizer were applied together,the capacity of biological nitrogen fixation in soil increased obviously. Compared with fertilizer treatment, the highest biological nitrogen fixation rate of wheat straw, corn straw and legume straw increased by 25 31%, 12 46% and 10 64% respectively The biological nitrogen fixation in soil is an important mechanism of storing fertilizer and securing fertilizer.