Résumé
To research the effect of continuous cropping on cotton soil microorganisms and soil microorgan-isms on grow of cotton,we studied the total numbers of aerobic self-nitrogen-fixing bacteria,potassium bacteria,cellulose decomposing bacteria,phosphate solubilizing bacteria,organic-phosphorus-dissolving bacteria distributed in continuous cropping cotton fields of regimental farm 2 and 3 of the first agricultural division through dilution spread plate method.Results showed that the total numbers of five kinds of bacte-ria was highest in blooming and bolling periods,lowest in seeding periods and higher in before sowing pe-riods.The total numbers of five kinds of bacteria was no notable regular changes with continuous cropping year.The numbers of aerobic self-nitrogen-fixing bacteria at different cotton growth stages in regimental farm 2 was higher than in regimental farm 3 and the numbers change of other bacteria was varied in different cotton growth stages in regimental farm 2 and 3.Soil beneficial bacteria were negatively correlated with a variety of soil nutrient ion and free-living nitrogen fixing bacteria were significantly positive correlated with soil total nitrogen.