Abstract：Taking soil for 5 years continnous cucumber cropping as material and utilizing pot culture method，
this experiment adopted 4 treatments： no soybean straw returning to the field（CK）； inoculation rhizobium
soybean straw returning to the field（T1）； inoculation rhizobium soybean straw with no root nodule returning to
the field（T2）； no inoculation rhizobium soybean straw returning to the field（T3），and studied the effect of
these treatments on soil sucrase activity and microbe quantity under different field moisture capacity. The results
showed that the fungi quantity in T1 was significantly lower than CK in 25％、50％ field moisture capacity for 50
to 140 days，and bacterial quantity maintained a high level in prophase of cultivation（＜ 50 days）. Under 75％
field moisture capacity，actinomyces quantity of the returning treatments was significantly higher than the control.
In a word，25％，50％ field moisture capacity could make the bacterial quantity maintaining a high level，and
reducing fungus quantity，the returning treatments were better than no returning treatments，inoculation rhizobium
treatments were better than no inoculation rhizobium treatments. The actinomyces quantity maintained a high level
under 75％ field moisture capacity in late culture stage（＞ 110 days）.
