长期施肥对农田黑土微生物群落功能多样性的影响

为了研究长期不同施肥对农田黑土微生物群落功能多样性的影响，采用Biolog ECO微平板培养法，对已经连续施肥35年的农业部哈尔滨黑土生态环境重点野外科学观测试验站4种处理(CK、NPK、M、MNPK)的两个土层(0～20、20～40 cm)微生物群落功能多样性进行研究.结果表明: 在0～20 cm土层，有机无机肥(MNPK)配施能够显著提高土壤微生物对碳源的利用能力以及群落代谢功能的丰富度、多样性和优势度，而在20～40 cm土层则低于单施化肥(NPK)处理，两个土层单施化肥均降低土壤微生物群落代谢均匀度.不同施肥处理土壤微生物对6种碳源的利用率在0～20和20～40 cm两个土层间存在差异，而在每个土层的处理间差异显著(P<0.05)，但各处理间的变化规律在两个土层中不一致.典范对应分析(CCA)结果表明，各处理土壤微生物群落代谢功能在0～20和20～40 cm土层间存在差异，且在两个土层的处理间也存在差异，而土壤养分含量对各处理土壤微生物群落代谢功能的影响规律在两个土层中较为相似.长期不同施肥会对耕层及以下土壤微生物群落功能多样性产生影响，在20～40 cm土层中单施化肥对微生物群落功能多样性的影响较大.

Effect of long-term fertilization on microbial community functional diversity in black soil.

In order to study the effects of long term different fertilization on microbial community functional diversity in arable black soil, we examined microbial metabolic activities in two soil la yers (0-20 cm, 20-40 cm) under four treatments (CK, NPK, M, MNPK) from a 35-year continuous fertilization field at the Ministry of Agriculture Key Field Observation Station of Harbin Black Soil Ecology Environment using Biolog-ECO method. The results showed that: in the 0-20 cm soil layer, combined application of organic and inorganic fertilizer(MNPK) increased the rate of soil microbial carbon source utilization and community metabolism richness, diversity and dominance; In the 20-40 cm layer, these indices of the MNPK treatment was lower than that of the NPK treatment; while NPK treatment decreased soil microbial community metabolism evenness in both layers. Six groups of carbon sources used by soil microbes of all the treatments were different between the two soil layers, and the difference was significant among all treatments in each soil layer (P<0.05), while the variations among treatments were different in the two soil layers. Canonical correspondence analysis (CCA) showed that soil microbial community metabolic function of all the treatments was different between the two soil layers, and there was difference among all treatments in each soil layer, while the influences of soil nutrients on soil microbial community metabolic function of all treatments were similar in each soil layer. It was concluded that long term different fertilization affected soil microbial community functional diversity in both tillage soil layer and down soil layers, and chemical fertilization alone had a larger influence on the microbial community functional diversity in the 20-40 cm layer.