保护性耕作方式对土壤碳、氮及氮素矿化菌的影响研究

Effects of tillage conservation on soil carbon,nitrogen and nitrogen mineralizing bacteria

采用稻田红壤免耕稻草覆盖方式种植红薯,研究保护性耕作方式对土壤碳、氮和氮素矿化菌的影响以及它们之间的相关关系。结果表明,保护性耕作能增加0～10cm土层土壤总有机碳、活性有机碳、全氮和碱解氮含量,降低土壤的碳氮比;保护性耕作处理的氨化细菌数量无论是在0～10cm土层还是10～20cm土层均比传统耕作处理高近1倍,而硝化细菌数量则是0～10cm土层高于传统耕作处理,且差异显著,10～20cm土层与传统耕作处理差异不大。说明保护性耕作能增加表层土壤碳、氮含量,降低土壤碳氮比,有利于氮素矿化菌的生长,为作物生长发育提供更多的速效氮素。

The present experiment was conducted using sweet potato with no-tillage and rice straw coverage in laterific soil of paddy field to study the effects of different tillage conservation modes on carbon, nitrogen and nitrogen mineralizing bacteria in soil and their correlation. The results indicated that conserving tillage could increase the content of total organic carbon, active organic carbon, total nitrogen and alkali-hydrolyzable nitrogen in the soil layer of 0-10cm, while decreased the C/N ratio in soil. The quantity of ammonifying bacteria in different tillage conservation treatments increased twice compared to traditional tillage in both, 0-10 as well as in 10-20cm soil layer. Further, the quantity of nitrifying bacteria in different tillage conservation treatment significantly differed from that of traditional tillage in 0-10cm soil layer, while no significant difference was observed in 10-20 em soil layer. These results demonstrated that conserving tillage could increase the contents of organic carbon and nitrogen, and decrease the C/N ration in soil which is beneficial for the growth of nitrogen mineralizing bacteria and provide more available nitrogen for the crops.