Abstract

Microbial communities play an important role in soil nutrient cycling. The present study aimed to evaluate the relationships of plant species, soil physical and chemical properties and microbial communities between high- and low-yield organically managed fruit orchards. The Biolog^TM and phospholipid fatty acids (PLFAs) analysis were used to evaluate soil microbial communities for eight typical organic orchards in Beijing, China. These included high- and low-yield agricultural sites for four types of fruit orchards: pear, peach, apple and grape. The soil properties including soil organic matter (OM), soil pH, soil total nitrogen (TN), soil available phosphorus (AP), soil available K (AK), cation exchange capacity (CEC), soil bulk density, soil porosity, microbial biomass and microbial activities were investigated. There were significant higher microbial biomass and lower bulk density in the soils of high-yield orchards than that in low-yield orchards. Differences between the paired soils of high- and low-yield orchards were highly associated with the average well colour development and total PLFAs.

Key words: Microbial community, biolog, substrate utilisation, phospholipid fatty acid,organic agriculture.