| Baoji-Tianshui highway is an important part of Lianyungang to Horgos′s trunk road in Gansu province, the national planning of "two vertical and two horizontal",is an important provincial channel that connection provinces of Gansu and Shanxi.Arbors, shrubs and herbs that are representative along the Baoji-Tianshui highway are selected to collect soil samples,measure soil physical and chemical properties, microbial quantity and the species composition of each sample point, the correlation of microorganism and environmental factors are analyzed, study the influence of Baoji-Tianshui construction on soil physical and chemical properties and soil microbes along the highway. The results are as follows:(1) Physical and chemical propertiesSoil moisture content, salt, PH, available nitrogen and available phosphorus content are characterized by natural forest is greater than the plantation, organic matter and available potassium content of natural forest is less than the plantation; Soil water content and organic matter content of mixed forest is greater than the pure forest, the soil salt, available phosphorus and available potassium content are characterized by mixed forest is less than pure forest.The highway construction changed the soil physical and chemical properties, but the change is small.(2) Microbial quantity characteristicsThe quantity characteristics of bacteria, antinomies and Aerobic sex authigenic nitrogen-fixing bacteria as the pure forest is greater than the mixed forest, fungi, organic phosphorus decomposition microbes and silicate bacteria features for the pure forest is less than the mixed forest. The number of cultivable microorganisms in natural forests and plantations characteristic is: the number of bacteria shows that natural forest is less than plantation, fungi, actinomycetes, organic phosphorus decomposition microbes, the silicate bacteria and Aerobic sex authigenic nitrogen-fixing bacteria is natural forest greater than plantations. Soil microbial number under the shrub and herbaceous plant are maximum, followed by herbs, shrub and herbaceous mix forests is minimum.The construction of Baoji-Tianshui highway reduced the number of culturable bacteria and fungi in the soil, but increased the number of actinomycetes; Aerobic sex authigenic nitrogen-fixing bacteria and organic phosphorus decomposition microbes are reduced in individual sampling point, but silicate bacteria are increased in most of sampling points, the possible reasons is available potassium content increased, and almost all available nitrogen and available phosphorus content decreased.(3)Microbial species compositionBacteria are mainly 10 genera, common genera have azotobacter, soil bacillus genus, micrococcus and bacillus genus; Fungi are mainly 8 genera, common genera are rhizopus, mucor, penicillium and aspergillus and trichoderma; actinomycetes fauna analysis shows that there are living with a certain number of actinomycetes in soil along highway ecosystem, but actinomyces species are simple, more than 90% belong to Streptomyces, in addition with a small amount of micromonospora.(4) The correlation of soil microbial quantity and environmental factorsBacteria are very significant negative correlation with altitude, significantly positively related to fungi, and positively correlated with available phosphorus; Actinomycetes is significantly negative correlation with soil salt content and very significant positive correlated to the available potassium content; Aerobic sex authigenic nitrogen-fixing bacteria and soil salt content has significant negative correlation, and available potassium content is very significant positive correlated; Organic phosphorus decomposing bacteria and Aerobic sex authigenic nitrogen-fixing bacteria were extremely significant positive correlation.(5) Soil habitat protection of road regionBase on the soil along highway, Soil habitat protection measures, such as, soil amelioration, road region greening and highway administration propose et al are put forward. |
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