东北黑土旱田改稻田对土壤团聚体微生物群落功能多样性的影响

为了解东北黑土旱田改种稻田后土壤团聚体中微生物群落功能多样性的变化,将东北黑土旱田(种植玉米为主)改种为稻田(简称“旱改稻”),采用Biolog-Eco微平板技术,研究了“旱改稻”后不同粒径土壤团聚体微生物的多样性指数以及其对碳源利用能力的变化。结果表明,“旱改稻”显著增加了黑土土壤水稳性微团聚体数量,增加了不同粒径土壤团聚体内有机碳(SOC)的含量。旱田和稻田不同粒径土壤团聚体内的土壤微生物群落平均颜色变化率(AWCD)表现为旱田淤泥+粘土>旱田大团聚体>旱田微团聚体>稻田大团聚体>稻田淤泥+粘土>稻田微团聚体。“旱改稻”明显降低了各粒径土壤团聚体微生物的多样性指数以及碳源利用能力,尤其对氨基酸与碳水化合物最为明显。主成分分析结果表明,旱田和稻田不同粒径土壤团聚体微生物群落功能多样性差异显著。综上,“旱改稻”明显改变了黑土土壤团聚体微生物群落功能多样性,降低了以碳源为底物的土壤微生物代谢活性。本研究结果为东北黑土区土壤可持续利用提供了理论参考。

Changes in Microbial Community Functional Diversity in Soil Aggregate of Black Soil Turned From Upland Into Paddy Tillage in Northeast China

In order to understand the changes of microbial community functional diversity in the soil aggregates after turning from upland into paddy tillage in black soil region of Northeast China, taking the black soil turned from upland (mainly planting corn) into paddy tillage (abbreviated as “land to paddy”) in Northeast China as a study object, the changes in microbial diversity index and the ability of carbon source utilization in all soil aggregates after “land to paddy” were investigated by using the Biolog-Eco microplate technique. The results showed that there was significant increased in the soil water-stable macro-aggregates number after “land to paddy” increased the content of soil organic carbon (SOC) in all soil aggregates. The average colour change rate of soil microbial community in all soil aggregates of different grain sizes in upland and paddy fields (AWCD) followed the order of upland silt + clay > upland macro-aggregates > upland micro-aggregates > paddy tillage macro-aggregates > paddy tillage silt + clay > paddy tillage micro-aggregates. The microbial diversity index and the ability of carbon source utilization in all soil aggregates obviously decreased by “land to paddy”, especially the carbon source of amino acids and carbohydrates. Results of principal component analysis showed that the function of carbon source utilization in all soil aggregates in upland and paddy tillage had changed. In summary, “land to paddy” obviously changed the microbial functional diversity in soil aggregate of black soil, and decreased the ability of carbon source utilization for soil microbial metabolic activity. This study provides a theoretical reference for the sustainable land utilization of Northeast China.