不同植物秸秆腐解特性与土壤微生物功能多样性研究

DECOMPOSITION CHARACTERISTICS OF DIFFERENT PLANT STRAWS AND SOIL MICROBIAL FUNCTIONAL DIVERSITY

采用网袋法探讨不同秸秆在3个长期试验地的腐解特征,结合Biolog微平板技术,对不同长期试验地土壤微生物群落多样性进行了研究。结果表明,随着腐解时间的增加,秸秆腐解的变化趋势为烘干秸秆>新鲜秸秆。葡萄园土壤微生物活性高,稳定性好,其次为桃园和农田。农田土壤微生物活性低、稳定性差,不同处理的秸秆在腐解过程中残留率变化较大,而果园土壤微生物活性相对较高、稳定性好,不同处理的秸秆在腐解过程中残留率变化较小。土壤碱解氮、速效磷和土壤温度与土壤微生物群落的三大指数呈极显著相关,且不同秸秆处理的腐解残留率与土壤微生物群落的优势度呈显著负相关,微生物群落在一定程度上影响了秸秆分解的速率。

Plant residues are an important source of soil organic matter. Decomposition characteristics of plant straws, soil microbial functional diversity and their relationship was studied so as to find some scientific basis for transfor- mation of organic carbon in soil and rational exploitation of land resources. The mesh bag method was used to explore how plant straws decompose in fields of three long-term field experiments and the biolog micro plate technology was adopted to determine soil microbial community diversities in the fields of the three long-term field experiments. Results show that with decomposition going on, residue rate of fresh plant straws did not varied much. The three long-term field experiments were basically similar in this aspect, displaying an order of FB （Fresh bean stalk） 〉 fc （Fresh corn stalk ＋ nitrogen fertilizer） 〉 FC （ Fresh corn stalk） , but residue rate of oven-dried milled corn stalk differed quite sharply. In terms of soil microbial community activity （average well color development, AWCD） , the three long-term experiments followed an order of Vine- yard 〉 Peach orchard 〉 Farmland, indicating it was the highest in the vineyard, while diversity index analysis indicates that the farmland did not differ much from the vineyard and peach orchard in all the soil microbial community indices, ex- cept for evenness, which did to a significant level. Principal component analysis of the Biolog 31 carbon sources reveals an order of farmland 〉 Peach orchard 〉 vineyard in terms of soil typical dispersion degree, indicating that the farmland was the lowest in microbial community stability and followed by peach orchard and vineyards. Analysis of microbial community structures utilizing the six categories of carbon sources indicates that significant differences existed between the three ex- periment fields in the utilization of amino acids and saccharides, while none in that of the other four. The three major indi- ces were extremely closely related to soil temperature, soil alkalytic nitrogen and, readily available phosphorus and, stalk decomposition residual rate was negatively related to dominancy of soil microbial communities, regardless of source of the stalk, which, to a certain extent, affected the decomposition rate of straws. In the farmland low in soil microbial activity and stability, stalk residue rate varied quite sharply between the treatments. While in orchards where the soils were rela- tively high in soil microbial activity and stability, stalk residue rate did slightly between the treatments.