东北地区玉米田长期免耕土壤碳氮及微生物活性的剖面分布特征

Effects of Long-term No-tillage on Soil-profile Characteristics of Soil Organic Carbon, Nitrogen and Microbial Activity in Corn Field of Northeast China

通过东北玉米田长期定位试验,比较分析了免耕和常规耕翻下土壤碳氮及微生物活性的剖面分布差异。结果表明:长期免耕显著提高了耕层(0～20cm)土壤有机碳(SOC)含量,其他各层差异不显著;免耕和翻耕之间,土壤总氮(TN)的浓度在各层次上差异均不显著;长期免耕下耕层土壤的碳氮比显著高于翻耕土壤,但其他各层差异不显著;长期免耕下耕层土壤的微生物活性略比翻耕的高,但其他层次基本一致。SOC、TN和微生物活性在整个土壤剖面上呈现类似的趋势,均随土层的加深而降低。耕层土壤的SOC含量是底层(60～100cm)的近4倍。

This study evaluated responses of soil carbon, nitrogen and microbial activity in soil profiles to long-term NT in a corn field of Northeast China. The results showed that the concentration of soil organic carbon（SOC） was increased in the plow layer（0 - 20 cm）, while no significant differences existed in other soil layers between different tillage regimes. Concentrations of total nitrogen（TN） did not significantly differ in any layers. Microbial activity was higher in NT than that in CT in the plow layer, although the difference was not statistically significant. There were similar trends of SOC, TN, and microbial activity in soil profiles, decreasing along with the increasing soil depth. Consequently, the concentration of SOC in the plow layer was almost 4 times higher than that in the bottom layer（60 - 100 cm）.