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为了探明保护性耕作条件下有机碳循环与农田地力提升机制,为保护性耕作技术的推广应用提供科学理论支撑,笔者以保护性耕作长期试验地为平台,研究不同耕作处理对总有机碳、全氮及其不同组分在潮土中含量的影响。笔者通过研究不同耕作处理下土壤总有机碳、全氮、溶解性有机碳、溶解性有机氮、微生生物量碳、易氧化有机碳在不同土层深度中的分布情况,揭示保护性耕作措施对潮土碳、氮含量的影响。结果表明:相比于常规翻耕,2年或4年翻耕1次的间歇性翻耕和全免耕处理0~5 cm土层土壤总有机碳含量分别提高了1.81%、6.43%、14.04%,全氮含量分别提高了0.80%、10.04%、7.93%,免耕处理下10~20cm土层中总有机碳、全氮含量显著低于其它处理;秸秆还田条件下,实施间歇性翻耕和免耕能显著提升0~5、5~10 cm土层中土壤溶解性有机碳、氮含量;相比于常规翻耕,间歇性翻耕、免耕处理下0~5 cm土层土壤微生物量碳与易氧化有机碳含量均有不同程度地升高,免耕处理下10~20 cm土层中微生物量碳含量显著低于其它处理;秸秆还田对0~10 cm土层土壤总有机碳、全氮、溶解性有机氮及其它活性有机碳组分含量均有不同程度的提升作用。总体来看,保护性耕作措施有利于表层0~5 cm土层中碳、氮储量的增加,免耕条件下“养分表聚”的负面效应可通过间歇性翻耕得到改善。
In order to find out the mechanism of organic carbon cycling and farmland enhancement under conservation tillage and to provide scientific support for the popularization and application of conservation tillage, the author studied the effects of different tillage treatments on total organic carbon, Effect of total nitrogen and its components on the content of alluvial soil. By studying the distribution of soil total organic carbon, total nitrogen, dissolved organic carbon, dissolved organic nitrogen, microbial biomass carbon and organic carbon in different soil depths under different tillage treatments, the author reveals that conservation tillage measures Impact on the content of carbon and nitrogen in alluvial soil. The results showed that soil total organic carbon content increased by 1.81%, 6.43% and 14.04, respectively, in 0 ~ 5 cm soil layer after two-year or four-year tillage with two-year or four-year tillage % And total nitrogen increased by 0.80%, 10.04% and 7.93%, respectively. The contents of total organic carbon and total nitrogen in 10-20 cm soil layer under tillage were significantly lower than those under other treatments. Under the straw returning condition, Compared with conventional tillage, intermittent tillage and zero tillage treatment, tillage and no tillage could significantly increase soil dissolved organic carbon and nitrogen in 0 ~ 5,5 ~ 10 cm soil layer Microbial biomass carbon and readily oxidizable organic carbon content increased to some extent. Soil microbial biomass carbon content in 10-20 cm soil layer under no-tillage treatment was significantly lower than that in other treatments. Organic carbon, total nitrogen, dissolved organic nitrogen and other active organic carbon components have different levels of promotion. On the whole, conservation tillage was beneficial to the increase of carbon and nitrogen reserves in 0-5 cm soil layer, and the negative effect of “nutrient pooling” under no-tillage could be improved by intermittent tillage.