Abstract
Organic agriculture is generally considered to improve the structure of the soil microorganism community. However, detailed studies have not yet been conducted. Therefore, we analyzed the structure of the soil microbial community in organic and conventional farming by the PLFA (Phospholipid Fatty Acid) method and determined whether there was a difference in the PLFA composition between organic and conventional farming. We used soil samples from cherry tomato farm fields in Fukushima and Yamagata prefectures, Japan, during a three-year period. The total concentration of PLFA, Shannon index H' and the ratio of specific biomass based on the PLFA signature did not reveal any differences between organic and conventional farming. Cluster analysis based on the PLFA composition, did not enable to detect any significant differences in the soil microbial community structure between organic and conventional farming. RDA (Redundancy Analysis) showed that the PLFA composition was markedly affected by the soil chemical properties and that soil nutrient accumulation was one of the factors for the changes in the soil microbial community structure. In addition, the agricultural practices used in organic and conventional farming were not significantly reflected in RDA. Therefore, it was concluded that the structure of the microbial community structure was not different between organic and conventional farming.
