短期放牧对草甸草原土壤微生物与土壤酶活性的影响

Effect of short-term grazing on soil microorganisms and soil enzyme activities in Meadow Steppe

摘要:

【目的】为呼伦贝尔草甸草原生态系统的保护、恢复及重建提供微生物学基础数据。了解草原土壤微生物和酶活性对放牧强度的响应。【方法】分别采集六个不同放牧强度的土壤样品, 测定土壤微生物数量、土壤微生物量和土壤酶活性, 分析短时期不同放牧强度土壤微生物数量、土壤微生物量和土壤酶活性的变化特征及其相互关系。【结果】不同放牧强度下, 菌群数量分布为细菌>放线菌>真菌; 土壤微生物数量、微生物量均表现为放牧区高于对照区; 在土壤表层(0?10 cm), 土壤过氧化氢酶、转化酶和蛋白酶活性表现出随放牧强度的增加先上升后略降的趋势, 且放牧区均高于对照区, 与土壤表层比较, 在较深层(10 cm?20 cm), 土壤细菌、真菌的数量和微生物量碳、氮下降幅度随放牧强度的增大而增大。土壤微生物数量、微生物量及土壤酶活性的垂直分布为0?10 cm>10 cm?20 cm。相关分析结果表明: 放牧干扰条件下, 土壤微生物数量与微生物量之间均存在显著或极显著的相关性。土壤酶活性与微生物数量、微生物量密切相关, 过氧化氢酶、转化酶与细菌、放线菌极显著相关(P<0.01)、与微生物量碳显著相关(P<0.05); 蛋白酶与真菌及微生物量碳、氮极显著相关(P<0.01), 与细菌显著相关(P<0.05)。【结论】适度放牧可使土壤微生物数量、微生物量和土壤酶活性增加。土壤微生物数量、微生物量与土壤酶活性之间具有密切关系。

Abstract:

[Objective] In order to provide microbiology basis for protection, restoration and reconstruction of meadow steppe ecosystem in Inner Mongolian Region. To investigate the response of grassland soil microbes and enzyme activity in different grazing intensity. [Methods] Soil samples were collected from six different grazing intensity, the variation of different grazing intensities on the soil microorganisms, soil microbial biomasses (Carbon and nitrogen), soil enzyme activity and the interrelationship among them were analysised. [Results] The reseults showed that the number of microorganisms in different grazing areas had the same changing trends: bacteria>actinomycetes>fungi. The number of soil microorganisms and soil microbial biomass (Carbon and nitrogen) were higher in grazing areas than no-grazing areas. In 0?10 cm soil depth, the trend of the activities of catalase, invertase and protease was performed increased first and then decreased along with the increasing of grazing intensity, Moreover the activities of these enzymes in grazing areas was higher than no-grazing area. Compared with 0?10 cm, the descending range of the number of bacteria and fungi and the microbial biomasses (Carbon and nitrogen) were increased along with the increasing of grazing intensity in 10 cm?20 cm soil depth. The number of soil microorganism, soil microbial biomass, the activity of soil enzyme were higher in soil depth 0?10 cm than 10?cm?20 cm in the vertical distribution. Correlation analysis indicated that the number of soil microorganism was significantly correlated with soil microbial biomass. The soil enzyme activitiy was positively related to the number of soil microorganism and soil microbial biomass. The activities of catalase and invertase were extreme-significantly correlated with the number of bacteria and actinomycetes (P<0.01), and significantly related to soil microbial biomass C?(P<0.05); the activity of the protease was extreme-significantly correlated with the number of fungi and soil microbial biomass C、N (P<0.01), and significantly related to the number of bacteria (P<0.05). [Conclusion] Moderate grazing incereases soil microorganisms, soil microbial biomasses and soil enzyme activity. There were positive correlations between soil microorganisms, soil microbial biomasses and soil enzyme.