耕作方式对土壤微生物和土壤肥力的影响

通过2年田间定位试验,对比研究了免耕+秸秆覆盖、旋耕+秸秆覆盖和传统耕作:三种耕作方式对土壤温度、土壤呼吸速率、土壤微生物数量和土壤肥力状况的影响.结果表明:秸秆覆盖对地温的影响存在"双重效应";土壤温度、土壤呼吸速率和土壤微生物量碳三者之间存在凸面关系;秸秆还田后耕作措施对土壤0～10和10～20 cm的微生物数量的影响不同,但均能增加土壤微生物量;土壤微生物能够加快秸秆中的有机碳向土壤有机质的转化速率;土壤微生物量碳可以作为反映土壤生产力状况的重要生物学指标之一.

Effect of different farming methods on soil microbial biomass and soil fertility

The ability of agrosystems to increase soil organic matter by sequestering atmospheric CO_2 and restoring organic matter pools is of importance for crop production. An experiment was conducted over 2006 to 2008 cropping years to investigate the dy-namics of soil microbial biomass and soil fertility in wheat (Triticum aestivum L.) fields. The results showed that residue retention had dual effects on soil temperature. A positive relationship between soil temperature and soil respiration rate was consistently ob-served over these years. Residue retention increased soil microbial biomass at 0～10 and 10～20 cm depths with three planting meth-ods. Soil microorganism enhanced the transformation of straw organic carbon to soil organic matter. Based on these data, we con-clude that soil microbial biomass may be as a biological indicator to reflect soil productivity.