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通过“棉花+小麦”轮作施用沼渣的定位试验,研究不同年限的沼渣施用对土壤剖面微生物量C、N(MBC、MBN)分布特征的影响。结果表明:在0~50cm剖面上,施用沼渣1年对0~30cm土壤的MBC、MBN影响较大,能显著提高30~40cm土层土壤MBC、MBN的含量,施用沼渣5年时对40~50cm土层MBC、MBN无明显影响。土壤MBC、MBN含量总体随施用沼渣年限的延长而增加,各土层MBC、MBN含量增幅随着施用年限的延长呈现不同趋势。施用沼渣1年,耕层土壤的MBC/MBN值较习惯耕作增加,施用沼渣3年后,其值呈降低趋势。各土层的MBC/TOC、MBN/TN和MBC的变化趋势基本一致,总体随着沼渣施用年限的延长而增加。针对“棉花+小麦”轮作模式,持续施用沼渣3年更有利于改善0~40cm土层土壤肥力。
The effects of biogas residue application on the distribution characteristics of soil microbial biomass C, N (MBC, MBN) in soil profile were studied through the location experiment of biogas residue applied on “cotton + wheat” rotation. The results showed that the application of biogas residue in 0 ~ 50cm section had a significant effect on the MBC and MBN of 0-30cm soil layer, and significantly increased the content of MBC and MBN in the soil layer of 30-40cm soil layer at 5 ~ MBC and MBN in 40 ~ 50cm soil layer had no obvious effect. The contents of MBC and MBN in the soil generally increased with the increase of the duration of biogas residues. The increases of MBC and MBN contents in different soil layers showed different trends with the extension of the application years. After applying biogas residue for one year, the MBC / MBN of topsoil increased more than that of conventional farming. After 3 years of biogas residue removal, the value decreased. The change trends of MBC / TOC, MBN / TN and MBC in different soil layers are basically the same, and generally increase with the application of biogas residues. For the “cotton + wheat” rotation mode, continuous application of biogas residue for three years is more conducive to improving soil fertility in 0 ~ 40cm soil layer.