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于2011年8月底对神农架自然保护区沿海拔变化的4种林型的土壤微生物生物量碳、氮进行研究,探讨土壤微生物生物量的变化规律和主要的环境影响因子。结果表明:表层土壤(0~10 cm)微生物生物量碳(MBC)和微生物生物量氮(MBN)含量大小顺序均为:亚高山灌丛>寒温带针叶林>针叶落叶阔叶混交林>落叶阔叶林。土壤微生物生物量碳、氮均随海拔的升高而显著增加,与土壤有机碳和全氮的变化趋势一致,而微生物商(q MB)随海拔表现出先减小后增加的趋势。Pearson相关分析表明,土壤微生物生物量碳、氮随海拔的变化趋势与土壤有机碳和土壤全氮呈显著正相关(P<0.05),但与土壤湿度、土壤温度和土壤p H呈显著负相关(P<0.05)。因此,土壤湿度、温度、p H、有机碳和全氮可能是影响土壤微生物生物量碳、氮沿海拔梯度变化的重要因子。
At the end of August 2011, the soil microbial biomass C and N in four forest types with different altitudes along Shennongjia Nature Reserve were studied to investigate the variation of soil microbial biomass and the main environmental impact factors. The results showed that the order of MBC and MBN in surface soil (0-10 cm) was as follows: subalpine shrubs> frigid temperate coniferous forest> coniferous and deciduous broad-leaved mixed forest > Deciduous broad-leaved forest. Soil microbial biomass C and N both increased significantly with the elevation, which was consistent with the trend of soil organic carbon and total nitrogen. However, the q MB of commercial soil showed a trend of decreasing and then increasing with elevation. Pearson correlation analysis showed that the trend of soil microbial biomass C and N with altitude was significantly and positively correlated with soil organic carbon and soil total nitrogen (P <0.05), but negatively correlated with soil moisture, soil temperature and soil p H (P <0.05). Therefore, soil moisture, temperature, p H, organic carbon and total nitrogen may be important factors affecting the variation of soil microbial biomass carbon and nitrogen along the altitudinal gradient.