Distribution of phosphobacteria in rhizosphere soils of four crops in Northeast China

Ecological distribution of phosphobacteria in soil rhizosphere of four typical crops (Triticum aestivum, Oryza sativa, Zea mays and Glycine max) in the northeastern China was determined based on four principal features (bacteria quantity, community structure, diversity and similarity). The results show vast amounts of both phosphate-dissolving and phosphate-solubilizaing bacteria, which are in the ranges of 2.15~6.68×105 cfu·g^-1 and 0.7~3.9×104 cfu·g^-1 respectively. Correlation analysis shows no significant correlation between available P content and phosphobacteria amount in the rhizosphere soils of the four crops. Population structure of phosphobacteria is very complicated in the northeastern China. The phosphate-dissolving bacteria in rhizosphere soils of T. aestivum,/i>, O. sativa, Z. mays and G. max consist of 9, 11, 13 and 12 genera respectively, while phosphate-solubilizaing bacteria consist of 9, 8, 9 and 7 genera respectively. Shannon-Weiner biodiversity of phosphobacteria in rhizosphere soils of the four crops is high. Shannon-Weiner biodiversity index of phosphate-dissolving bacteria is higher than that of phosphate-solubilizing bacteria. Sorenson similarity coefficient is also high (0.50~1.00), and higher for phosphate-solubilizing bacteria.