休耕轮作对农田土壤微生物量碳的影响

Effect of Fallow Rotation on Microbial Biomass Carbon in Farmland

以休耕轮作13年黑土农田为研究对象,探讨耕层土壤中微生物量碳(MBC)对不同耕作方式的响应及其影响因素。结果表明:耕层土壤中,休耕轮作下覆盖带、休闲带MBC平均含量分别比常规耕作高17.27%、8.92%(P<0.05);覆盖带MBC含量比种植带和休闲带高17.64%、7.66%(P<0.05)。MBC含量土层差异极显著(P<0.01),休耕轮作和常规耕作处理下表层土壤MBC含量明显高于下层土壤,休耕轮作的三个条带及常规耕作下的MBC均随土壤深度降低而降低;0~10 cm土层MBC含量显著高于10~20 cm、20~40 cm土层。休耕轮作及常规耕作条件下MBC含量均随土壤深度增加而降低,达极显著差异水平(P<0.01),土壤MBC的变化主要受到土壤活性组分与水热状况的影响,土壤MBC与易氧化态碳(EOC)、水溶性碳(DOC)均呈显著正相关(P<0.05);休耕轮作有利于耕层中水分与温度的保持,为微生物提供了适宜的生存条件,更有利于微生物的生长繁殖,促进MBC含量高于常规耕作处理。

Based on a long-term（13 years） tillage farmland on Black Soil of Northeast China, we determined the effects of tillage method including fallow rotation and ridge tillage on soil microbial biomass carbon（MBC）. The results showed that the average content of MBC in coverage belt and fallow belt was higher 17.27% and 8.92% respectively,under fallow and rotation tillage than under traditional tillage. The MBC content in coverage belt was 17.64%, 7.66%higher than that in fallow planting and fallow belts in the arable layer. The contents of soil MBC under fallow and crop rotationwere significantly higher in 0-10 cm soil depth than that in 10-20 cm and 20-40 cm soil depths. The contents of MBC were mainly affected by active components in soil and hydrothermal conditions. The contents of soil MBC and easily oxidizable organic carbon（EOC） and dissoluble organic carbon（DOC） had significantly positive correlation（P〈0.05）. Fallow and crop rotation kept moisture and temperature in the top layer, which provideda suitable living conditions for the growth of microorganisms and promoted the MBC content compared with conventional tillage.