长期不同施肥制度下几种土壤微生物学特征变化

 为阐明土壤微生物对土壤健康的生物指示功能, 以国家褐潮土肥力与肥料效益监测基地的长期肥料试验为平台, 应用BIOLOG ECO微平板培养法与常规分析法研究了长期施肥15年后不同施肥制度对土壤微生物生物量、活性、群落代谢功能多样性及土壤肥力的影响。研究结果表明, 与对照(CK)相比, 长期化肥与有机肥配施土壤中土壤有机质(SOM)、全氮(STN)、全磷(STP)含量升高, 土壤C/N与pH值降低, 土壤微生物量碳(Soil microbial biomass carbon, SMBC)、生物微生物量氮(Soil microbial biomass nitrogen, SMBN)、微生物商(qMB)及脲酶(Urease)活性升高, BIOLOG ECO微平板平均颜色变化率(Average well color development, AWCD)、土壤微生物代谢功能多样性指数变化不明显。和长期单施化肥处理(NPK)相比, 长期化肥与有机肥配施处理中上述几种微生物学特征(SMBC、SMBN、qMB、Urease及AWCD、代谢功能多样性指数)均呈极显著增加。NPK处理与CK相比虽然SOM、STN、STP含量稍有升高, 土壤C/N与pH值降低, SMBC、SMBN、qMB及Urease活性增高, 但是AWCD、土壤微生物代谢功能多样性指数却显著下降。过氧化氢酶活性(Catalase)在各处理土壤中的差异不显著。土壤微生物碳源利用的主成分分析表明, 长期不同施肥各处理在土壤微生物利用碳源的种类和能力上有差异。此试验说明, 土壤微生物受农业管理措施和多种环境因素的影响, 土壤微生物学特征可作为土壤质量的敏感指标, 为提高作物产量、增强肥力提供理论参考。

CHANGES OF SOIL MICROBIAL PROPERTIES AFFECTED BY DIFFERENT LONG-TERM FERTILIZATION REGIMES

Aims Soil health is important for sustainable development of terrestrial ecosystems. We studied soil microbial properties such as microbial biomass, functional diversity of microbial communities and soil enzyme activities in order to illustrate the function of soil microbial properties as bio-indicators of soil health. Methods A 15-year fertilizer experiment on Fluvo-aquic soil in Changping County, Beijing, China, was established in a wheat-maize rotation in 1991 to explore long-term impact of four different fertilization regimes: no fertilizer (CK), mineral fertilizers (NPK), mineral fertilizers plus swine manure (NPKM) and mineral fertilizers with maize straw incorporated (NPKS). We used BIOLOG ECO micro-plate analysis to study the functional diversity of microbial communities. Important findings Long-term fertilization regimes had clear effects on soil microbial properties compared to CK. Soil microbial biomass C &; N, urease activity, soil organic matter, soil total nitrogen, and soil total phosphorus increased more with NPKM and NPKS than with NPK and CK. The utilization ability of microbial communities for carbon and functional diversity of microbial communities increased to some extent with NPKM and NPKS, but had no significant differences with CK. NPKM and NPKS could significantly decrease soil pH and C/N. The utilization ability of microbial communities for carbon and the functional diversity of microbial communities under CK were much higher than those under NPK since the other soil microbial properties were higher under NPK treatment. Catalase activity had no obvious differences among the four treatments. Principal component analysis of carbon utilization for soil microbial communities indicated there were different carbon substrate utilization patterns among the fertilization treatments.