西藏中部农田土壤复退过程中的生物学特征

Microbes Characteristics of Soil Rehabilitation in Central Tibet

在西藏中部春播条件下,就不同培肥方式对土壤剖面微生物区系及其主要生理类群变化的影响,以及土壤微生物与土壤有机质、土壤养分的相互关系进行了研究。结果表明,细菌、放线菌、纤维素分解菌的土体差异较大,并主要集中于耕层;真菌、固氮菌的土体差异则极小。2～30,31～60cm土层土壤细菌在微生物区系构成中均占绝对优势,化肥对调控土壤细菌数量具有重要作用。不同培肥方式对2～30,31～60cm土层土壤真菌、固氮菌以及2～30cm土层土壤放线菌的繁殖普遍具有不同程度的抑制作用;2～30,31～60cm土层固氮菌与纤维素分解菌均呈负相关。土壤微生物与土壤有机质的相互促进作用较为明显,对提高土壤有效氮、有效磷亦具重要作用。

A spring-wheat field trial was carried out to investigate the effects of different organic or inorganic fertilizer applying manner on the soil microflora characteristics and its primary microbial population of the degraded soil and the interactions among the soil microbes and organic matter, available nutrient in central Tibet. The results were shown that the bacterium, actinomyces and cellulose-decomposing bacterium is distributed mainly over 2～30 cm horizon. Quantitative difference of fungus and N-fixing bacteria was not quite clear in 2～30 cm,31～60 cm horizon. Bacteria was dominant group in biome of the soil microbe community in all layers of the soil profile. Chemical fertilizer had significant effectiveness on the regulate the bacterium. Propagation of fungi and N fixing bacteria in the layers of 2～30 cm, 31～60 cm and of actinomyces in 2～30 layer cm soil layer were suppressed by fertilization. Nitrogen-fixing bacteria reduced by the increase of the cellulose-decomposing bacterium in different horizon. All different methods of application had significant and prompt effectiveness on the coordinating of soil environment, on enhancing the accumulation of soil organic matter and on increasing the pool of N and P comparing with non-fertilization.