华北土石山区刺槐和栓皮栎人工林土壤微生物数量和微生物量碳、氮研究

正截止到2014年,全国水土流失面积已高达294.91万km2,占国土总面积的30.72%1-2]。水土流失造成生态环境脆弱,植被破坏促使水土流失加剧是区域环境恶化的主要原因之一3]。众多研究表明,植被恢复可有效地减少水土流失,是遏制生态环境恶化、改善脆弱生态系统的有效措施4-6]。在森林生态系统中,土壤微生物对土地利用的变化、管理措施、耕作和肥力水平等外界条件的变化十分敏感,

Studies on Soil Microorganism Quantity and Soil Microbial Biomass Carbon and Nitrogen of Robinia pseudoacacia and Quercus varaibilis Plantations in North China

Objective] In order to provide the theoretical basis for evaluating the effect on soil microbial properties and for establishing reasonable sustainable forest management to reduce soil erosion and land degradation, soil chemical properties and microbial biomass of main tree species-Robinia pseudoacacia and Quercus varaibilis in rocky mountain area of northern China were studied. Methods] The chemical properties, microorganism amount, microbial biomass carbon and nitrogen in soil of R. pseudoacacia and Q. varaibilis plantations were analyzed. The factors influencing soil fertility were also studied with principal component analysis and stepwise regression analysis. Results] The results showed that three kinds of main soil microorganisms and microbial biomass carbon and nitrogen decreased with the deepening of the soil depth. The amount of soil bacteria in the R. pseudoacacia plantation was 2.13-2.26 times that in the soil of Q. varaibilis plantation. While the amount of actinomycetes in the soil of Q. variabilis plantation was 4.48-6.05 times that in the soil of R. pseudoacacia plantation. No obvious difference was observed between the amounts of fungi in these two kinds of forest soil. The content of nitrate nitrogen, organic matter, available phosphorus and the total amount of microbes, microbial biomass carbon and nitrogen in the soil humus layer of R. pseudoacacia plantation were significantly higher than that of Q. variabilis plantation. Conclusion] (1) The soil physical and chemical properties and the number of microorganisms and microbial biomass carbon/nitrogen could be used to reflect the variability of soil fertility in this area. (2) The main factors affecting the total amount of microbes and microbial biomass carbon/nitrogen are total nitrogen, available phosphorus and available potassium. (3) Planting R. pseudoacacia is more conducive to the ecological restoration of soils than planting Q. varaibilis.