Effect of Different Soil Types and Growth Stage on Number of Microorganisms in Rhizosphere of Wheat

To explore the effect of different soil types and growth stage on the number of microorganisms in wheat rhizosphere,microorganisms in wheat rhizosphere were isolated from different soil types at different growth stage,and the changes of their quantities were studied.The results showed that the number of microorganisms in wheat rhizosphere was affected by soil types at all wheat growth stage,and decreased with the decrease of soil organic matter content,in which the number of fungi and bacteria decreased significantly.With the advance of wheat growth period,the number of fungi and bacteria in the red clay,loam,sandy loam increased from jointing to filling stage,up to the maximum at filling stage,and then decreased with the gradual maturation of wheat.The number of actinomycetes in red clay had the same trend as fungi and bacteria,and decreasing-increasing-decreasing trend in loam,also up to the maximum at filling stage,with an increasing trend in the sandy loam from jointing to heading stage,then beginning to stabilize.