The soil nutrients

microorganism quantity and enzyme activity are studied and analyzed in artificial grassland with different cultivation years in the headwater area of Yangtze and yellow rivers.The results are as follows: soil nutrients of artificial grassland decreased and then increased regularly with change of the cultivation years.The soil nutrient content of two aged artificial grassland was highest

and the six aged grassland lower than two aged

and both of them were significantly higher than the four aged.The changes of soil bacterium and actinomycetes were consistent with the soil nutrients.Similarly

the soil urease

catalase and neutral phosphatase activities have equal regularities. The quantities of fungi descended with the increase of cultivation years.Meanwhile

the soil nutrients

microbial quantities and enzyme activities decreased with the increase of soil depth.The canonical correlation analysis showed that soil bacterium had the best correlation with soil organic matter

total nitrogen

effective K and pH value;soil urease and catalase activities had the best correlation with soil organic matter

total nitrogen

effective nitrogen

effective K and pH value.So the soil microorganism and enzymes can be used as evaluation index of soil fertility.