Based on sample collection

field monitoring

and indoor experiments

the effects of different types of Grain-for-Green on soil quality were investigated in Huangshui drainage area of Qinghai Province.The results of sample analysis indicate the forests with the same age(8a)in the order of decreasing soil organic matters

total porosity

and total amount of microorganism as:mixture of Picea crassifoliaand birch>birch >mixture of Picea crassifolia and Hippophae rhamnoides>Picea crassifolia>Hippophae rhamnoides> farmland;in order of decreasing soil bulk density and pH value as:mixture of picea crassifolia and birch> birch>mixture of Picea crassifolia and Hippophae rhamnoides>Picea crassifolia>Hippophae rhamnoides> farmland;in the order of decreasing water holding capacity as:mixture of Picea crassifolia and birch>Hippophae rhamnoides>birch>Picea crassifolia>farmland;in the order of decreasing erosion resistance( K)as:Hippophae rhamnoides>mixture of Picea crassifolia and birch>mixture of Picea crassifolia and Hippophae rhamnoides>birch>Picea crassifolia>farmland;and in the order of decreasing heat capacity as:mixture of Picea crassifoliaand birch>birch>mixture of Picea crassifoliaand Hippophae rhamnoides> Hippophae rhamnoides>Picea crassifolia>farmland.The results also show soil microorganisms in the order of decreasing total amount as:bacteria>actinomycetes>epiphyte.Specifically

bacteria accounted for over 95percent of the total microorganism.