Objective  The effect of fertilization on soil phosphatase activities and its main influencing factors are needed to be clarified.

  Method  Based on a long-term located experiment of yellow soil for 22 years, the effects of long-term application of chemical fertilizer and organic fertilizer on soil nutrients and the activities of acid phosphatase (ACP), neutral phosphatase (NEP) and alkaline phosphatase (ALP) in paddy and dryland soils were studied.

  Result  The results showed that long-term different fertilization treatments significantly changed soil nutrients, and the effects on soil pH, organic matter and available phosphorus were different in paddy and dryland. The activities of ACP and NEP in paddy and dryland soils were higher than that of ALP. Compared with no fertilization treatment, the application of chemical fertilizer had no significant effect on phosphatase activities except for individual treatments in paddy, and the NEP activities in the manure treatments were significantly increased by 15.8% - 27.1%. The NK, NP and NPK treatment in dryland significantly increased ACP activities by 14.2% - 29.0%, but decreased ALP activities by 20.1%-50.7%. The manure treatments increased ACP and ALP activities by 11.7%-17.7% and 9.4% - 56.9%, respectively, but decreased NEP activities by 10.5%-32.3%. Compared with balanced fertilization treatment, the nutrient deficiency fertilization treatments on phosphatase activities were not significant effect in paddy. The manure treatments increased ACP, NEP and ALP activities by 9.1%-18.5%, 6.9%-17.3% and 8.3%-15.0%, respectively. In dryland, NK treatment significantly increased ACP and NEP activities by 12.9% and 12.9%, but PK treatment significantly decreased ACP and NEP activities by 16.7% and 18.9%, and the NEP activities decreased by 5.9%-28.9% and the ALP activities increased by 50.1%-115.3% in manure treatments. Correlation analysis showed that NEP activities were significantly correlated with soil nutrient contents, but the correlation was opposite in paddy and dryland. ALP activities were significantly positively correlated with organic matter and microbial biomass phosphorus in paddy and dryland. Path analysis showed that the phosphatase activities were directly affected by soil phosphorus except ALP activities in dry land directly affected by pH.

  Conclusion  Soil phosphatase activities are closely related to soil phosphorus availability in yellow soil. application of manure is an effective way to improve soil phosphatase activity in paddy. While long-term application of chemical nitrogen fertilizer, especially NK treatment, could improve ACP activities and increase soil phosphorus supply in dryland, and the application of manure could increase ALP activities by increasing soil pH.