不同培肥模式对茶园土壤微生物活性和群落结构的影响

以闽东地区红黄壤茶园定位实验地为对象,通过测定6种不同施肥处理土壤微生物学特性,研究不同培肥对土壤微生物特性和生物化学过程的影响,阐明各指标间的相互关系.结果表明,除了单施无机肥处理外,半量化肥+半量有机肥、全量有机肥、全量化肥+豆科绿肥以及半量化肥+半量有机肥+豆科绿肥等的培肥方式均不同程度提高了土壤有机质,可培养微生物数量,微生物量碳、氮含量及土壤酶活性,尤以半量无机肥+半量有机肥+豆科牧草的培肥模式增幅更为明显,而单施无机肥不利于微生物的生长、酶活性的提高和维持生态系统的稳定性.微生物群落磷脂脂肪酸(PLFAs)标记主成分分析显示,各种不同施肥方式使微生物群落结构发生改变.相关分析表明,微生物量与可培养微生物数量、微生物磷脂脂肪酸含量之间的相关性明显高于微生物量与各种酶活性之间的相关性,说明微生物数量大小对微生物群落结构的影响大于对酶活性功能的影响.研究也表明土壤各微生物指标能从不同方面反映土壤肥力水平,所以采用各种不同的方法能更客观地评价闽东地区茶园红黄壤质量的优劣.

Effect of different fertilization strategies on structure and activity of microbial community in tea orchard soils

This study aimed to evaluate the effects of long term addition of organic and inorganic amendments on relationship between soil microbial and biochemical properties varying microbial indicators based on Fu’an experimental field site in Fujian, China. Under half rate of chemical fertilizer + half rate of organic fertilizer, whole rate of organic fertilizer, whole rate of chemical fertilizer + leguminous green manure and half rate of chemical fertilizer + half rate of organic fertilizer + leguminous green manure treatments, soil organic contents, total numbers of culturable microbes, microbial biomass C, microbial biomass N and soil enzyme activities were significant enhancement, except inorganic fertilize treatment compared with control treatment. As compared to other treatments, “inorganic fertilizer + organic manure + leguminous green manure” treatment observed the highest number of culturable microbes, microbial biomass and enzyme activities, whereas treatment with inorganic fertilizer decreased the number of soil organisms, enzyme activities and the stability of tea orchard soil ecosystem. Furthermore, microbial community was determined by signature phopholipid fatty acids (PLFAs), showed obvious change under various fertilization strategies. The correlation between microbial biomass with phenotypic groups of organisms and cultural microbes was higher than those of culturable microbes and enzyme activities, indicating that the size of the microbial community showed intensify impact on its composition rather than on enzyme functional capacity in tea orchard soil ecosystem. It is suggested that soil microbial indicators could reflect different soil fertility levels. Thus, taking various measurements were considered as a good technique for evaluating tea orchard soil quality more objectively at eastern Fujian district.