Effects of aluminum stress on the microflora of red soil

The study deals with the effect of aluminum (Al) stress on the microflora of red soil in soybean pot culture experiment. The red soil in soybean pot culture experiment exhibited an increase in bacteria and actinomycetes when Al mass fraction was lower than 1.1 g/kg and a decrease when Al mass fraction was higher than 1.1 g/kg. Al had a significant and stimulative effect on soil fungi. Al had a similar effect on ammoniation bacteria, nitrifier and denitribacteria to bacteria and actinomycetes. The maximum ratio of Al inhibiting ammoniation bacteria, nitrifier and denitribacteria reached 48%, 96% and 95%, respectively. The number of azotobacteria was gradually reduced with increasing concentration of Al. Nitrifier or denitribacteria could be used as indicator bacteria for Al-polluted soil, and the critical mass fraction of Al was about 1.3 g/kg.