温室不同管理模式对土壤微生物生物量碳和原生动物丰度的影响

Effects of Different Management Practices on Microbial Biomass Carbon and Protozoa Abundance Under Greenhouse Conditions

为了解温室环境下不同的农业管理模式对土壤微生物生物量碳和原生动物的影响,以中国农业大学曲周日光温室长期定位试验为研究对象,于2012年8—12月进行了5次取样,测定了有机、无公害和常规管理模式下的土壤真菌、细菌生物量碳和原生动物丰度。结果表明:温室环境土壤以细菌分解途径占优势;原生动物中鞭毛虫占绝对优势。管理模式对土壤真菌生物量碳、细菌生物量碳、微生物生物量总碳、原生动物各类群(鞭毛虫、纤毛虫和肉足虫)丰度及总数均有显著影响,但对真菌/细菌比率、鞭毛虫和肉足虫的相对丰度没有显著影响。细菌、真菌和微生物生物量碳在不同管理模式间总体呈现相同的规律,即有机模式>无公害模式>常规模式;对于原生动物,不同类群呈现出复杂的动态变化规律,总体上有机模式下原生动物数量高于无公害和常规模式的。管理模式对微生物生物量碳和原生动物的影响主要体现在生物量上,而对功能群结构的影响较小。

Soil microbes and protozoa, as important members of soil biota, play key roles in soil ecological processes due to their abundances and communities closely associated with various agricultural activities. In this paper, a comparative study was conducted to study the effects of organic （ORG）, low input （LOW）, and conventional （CON） vegetable greenhouse systems on soil microbial biomass carbon （bacterial and fungal biomass carbon） and protozoa abundance. Soil samples were collected five times from August to December 2012 （an entire cucumber growing season） in the Quzhou Experimental Station of China Agricultural University. The results showed that the management practices significantly affected soil fungal biomass carbon, bacterial biomass carbon, microbial biomass carbon, flagellate abundance, ciliate abundance, amoeba abundance and total protozoa abundance, but did not affect the fungal to bacterial （FB） ratio and the relative abundances of flagellates and amoebae. Generally, soil bacterial, fungal, and microbial biomass carbon values were in an order of ORG 〉 LOW 〉 CON, and this trend was more obvious in 0-10 cm soil. FB ratio indicated a bacterial-based decomposition pathway in all three systems, which exhibited similar dynamic characteristics. For protozoa, flagellates dominated under all three management practices, with a mean proportion of 85.2%, followed by amoebae （13.1%）, and ciliates （1.7%）. The total protozoa under ORG management practice were higher than those under LOW and CON management practices. In conclusion, management practice mainly affects the biomass of microbes and protozoa, whereas little effect on the functional group structure of soil biota.