Communities of Heterotrophic Bacteria in Gleysoles and Planosoles of Irrigated Rice Fields

摘要

This work evaluated the effects of physical and chemical variables in the diversity of bacterial communities present in rice field soils in two areas of different regions of southern Brazil. The samples were collected along 2013/14 and 2014/15, in rice producing areas of the regions: Outer Coastal Plain (OCP) and Inner Coastal Plain (ICP), Rio Grande do Sul, Brazil. The results were analyzed using Component Principal Analysis (PCA), Canonical Correspondence Analysis (CCA), Diversity Index, and Analysis of Variance. Were recorded 29 Colony-Forming-Units (CFUs) in both regions and the diversity was similar differentiated only for different phenological phases of plants. Bacterial abundance of colonies corresponding CFUs in OCP was (F_(1.9) = 7.84 p < 0.05): 18.5% in before sowing; 22.3% in vegetative phase; 22.3% in reproductive phase and 36.9% during seed maturation. Bacterial abundance of colonies in ICP was (F_(1.9 )= 7.03 p < 0.05): 23.9% in before sowing; 21.7% in vegetative phase; 20.7% in reproductive phase and 33.7% during seed maturation. The first two axes of each crop fields generated by CCA in the 2013/14 crop explain 67% of the variation observed and in 2014/15 explain 86.5%. The most important variables for ordination and correlation with the axis were content of organic matter and clay. With an analysis of the entire dataset, the PCA explained 64.84% and a CCA explained 70.7% enter the main two axes, highlighting clay and organic matter. In both types of soils, gleysoles and planosoles, the CFUs of the following communities of heterotrophic bacteria were higher: Bacillus thuringiensis, Bacillus cereus, Lisinibacillus sphericus, Pseudomonas fluorescens, P. putida , Corinebacterium spp.