宁夏盐池沙地不同密度人工柠条林对土壤微生物的影响

Impact of Different Density of Caragana korshinskii Shrubs on Soil Microbes in Ningxia Yanchi

为了研究西北干旱风沙区植被恢复与土壤微生物的关系,以宁夏盐池退化沙地种植不同密度的人工柠条林为研究对象,用稀释平板法对3种不同密度柠条林及对照(封育沙地)土壤微生物分布特征进行了研究.结果表明,不同密度人工柠条林对土壤肥力和土壤微生物产生不同的影响.与对照相比,随着人工柠条林密度的增加,土壤肥力状况总体呈下降趋势.不同样地土壤中微生物数量差异显著,柠条林密度从大到小依次为1 665丛/hm^2,2 490丛/hm^2,3 330丛/hm^2,封育沙地,且4种类型的微生物群落数量随着土层深度的增加而明显减少.细菌数量与有机质、总氮、速效磷、速效钾的质量含量呈显著相关,与总钾的质量含量呈极显著相关;放线菌数量与总氮的质量含量极显著相关.可为在退化沙地改良过程中大面积营造柠条灌木提供参考.

This paper took the Caragana korshinskii shrubs with different density as the research object in degraded sandy land in Yanchi, and studied the distribution of the soil microbes in three different density Caragana korshinskii shrubs and the fenced sandy land through the dilution-plate method. The result showed that the Caragana korshinskii shrubs with different density had different impact on the soil fertility and the microbe quantity. The soil fertility decreased with the increase of the density of Caragana korshinskii shrubs. There were significant differences on the quantity of the soil microbes among the four kinds of sites. The order of quantity of soil microbes in the four kinds of sites is 1 665 strains/hm^2〉2 490 strains/hm^2〉3 330 strains/hm^2 〉fenced sandy land, and the quantity of the soil microbes decreased significantly with the increase of depth of soil layer in every site. The quantity of soil microbes was positively correlated with the soil nutrient： the quantity of bacteria was significantly correlated with the organic matter, the total N, available P, and was highly significantly correlated with available K; the quantity of actinomycete was highly significantly correlated with total N.