耕作方式对稻田土壤微生物量碳氮的动态影响

摘要

为了探讨不同耕作方式对稻田土壤微生物量碳氮动态变化的影响，本研究就长期免耕和常规翻耕两种耕作方式，针对水稻不同生育期稻田0～20 cm 土层土壤微生物量碳氮含量变化进行了分析。结果表明，免耕处理土壤有机质显著增加了13.09％。翻耕处理水稻各生育期土壤微生物量碳氮含量基本高于免耕处理。翻耕处理土壤微生物量碳含量在水稻种植前和收割后两个时期分别比免耕高20.58％和16.79％，差异显著，其他时期差异不明显；翻耕处理土壤微生物量氮含量在水稻分蘖后期、孕穗期、黄熟期、收割后四个时期分别比免耕高31.70％、38.42％、41.82％和98.96％，差异显著。免耕处理土壤微生物量碳氮比率基本高于翻耕处理。因此，免耕有利于土壤有机质的积累，而翻耕方式更有利于微生物活动，提高土壤微生物量碳、氮含量，并且翻耕处理有利于提高土壤氮素有效性。%To study the dynamic effect of different tillage methods on the soil microbial biomass carbon (SMBC)and soil microbial biomass nitrogen (SMBN)in rice paddy,long-term no-tillage (NT)and conventional tillage (CT)methods were used to analyze the content change of soil microbial biomass carbon and nitrogen in different growth stages on rice.The re-sults showed that the soil organic matter (SOM)content of the NT treatment increased 13.09% compared with the CT;the SMBC and SMBN contents of the CT treatment was higher than that of the NT treatment.The SMBC content of the CT treat-ment,before the rice planting and after harvesting is significantly higher than no-tillage treatment by 20.58% and 16.79%respectively;while the difference is not significant during the rice growing stages.The SMBN content of the CT treatment is significantly higher than that of the NT treatment in late tillering stage (by 31.70%),booting stage (by 38.42%),yellow ripening stage (by 41.82%),and after harvesting(by 98.96%).The soil microbial biomass carbon/nitrogen ratio in NT treatment is higher than that in CT treatment.Results suggest that no-tillage method is beneficial to SOC accumulation,con-ventional tillage method is good for the increasing of soil microbial,SMBC and SMBN content,and enhancing biological ef-fectiveness of soil nitrogen.