Study on Diversity of Culturable Bacteria in Maize Field Soil under Pesticide Stress

Abstract

The effects of pesticide application on the diversity of culturable bacteria in the soil of corn farmland in Sanjiang Plain were studied, and the bacteria capable of degrading acetochloramine in the soil samples were screened. In the black soil of corn farmland where “ethyldiazine 86” was applied, the experimental group and the control group were set, and the culturable bacteria in the soil samples of the two groups were cultured and screened by coating plate method. The 16S rRNA gene sequences and morphological characteristics were analyzed to determine the species of bacteria. Selective medium was designed to screen pesticide degrading bacteria. 19481 strains of culturable bacteria were cultured in the experiment, including 7854 strains in the experimental group and 11627 strains in the control group. A total of 65 strains were screened, purified and preserved, including 16 strains of phosphorus solubilizing bacteria, 9 strains of nitrogen fixing bacteria and 4 strains of pesticide degrading bacteria. The community structure of soil bacteria was mainly composed of Pseudomonas, Pantoea and Bacillus, and the dominant bacterium was Pseudomonas. The four pesticide-degrading bacteria were all Pseudomonas migulae. Long-term application of pesticides can reduce the number of culturable-bacteria in the soil, and the bacteria richness is also decreased. This study provides a theoretical basis for understanding the bacterial diversity of pesticide residue soil, protection and sustainable utilization of black soil.