Influence of Soil Moisture on Spatial and Temporal Variation of Microbial Communities in an Agroecosystem.

Bacteria play a pivotal role in soil complexity, vastness and diversity via various biological processes that are unique to prokaryotes. They hold the key for soil sustainably and functionality. Biotic and abiotic processes in soils are intimately related and interdependent, providing continuous feedback to each other. Among them, soil moisture is a major controller for microbial community structure and activity. Therefore, understanding of moisture effect on bacterial community distribution in agroecosystem may open up new avenues to enhance it productivity and sustainability. Microbial community composition in the soil inner space can be visualized and measured with modern molecular biological fingerprinting techniques, especially nucleotide sequencing. A field scale experiment was conducted to search for evidence of interactions between bacterial communities and soil moisture in agroecosystems. A cross-disciplinary approach was taken to link physics and biology in soil inner space. Soil moisture contents were determined at 45 evenly distributed sampling points over four deferent sampling times. Bacterial community composition and diversity were concurrently determined at the sampling locations using 454 16S rDNA gene-amplicon sequencing. Bacterial community structure and its distribution significantly correlated to field moisture patterns. Bacterial cluster separation in principal component analysis plot also revealed that community differences according to the sampling time and moisture content. Thus, it clear that field moisture level is a major driver to determine bacterial community structure variation in agroecosystems.