| Abstract: | The authors presented the enzyme characteristics of catalase, sucrase, urease and alkaline phosphatase under agroforestry
systems in northern Jiangsu Province. The results show that soil enzyme activities reduce gradually from top to bottom layer
of the soil profile, and the fluctuations of catalase and urease are smaller than those of sucrase and alkaline phosphatase.
Soil enzyme activities differe significantly in different samples, and the order is arranged as poplar-crop intercropping
segment (A, D) > paulownia-crop intercropping segment (B, C) > CK. Furthermore, soil enzyme activities increase with intercropping
age. On the other hand, in the same plot, there are closer relationships between enzymes in the soil samples. Catalase, alkaline
phosphatase and urease are negatively related, while alkaline phosphatase and urease are positively related (except in samples
B and C). In addition, the enzyme activities have a close relationship with the fertilizers. Catalase is positively correlated
with the soil pH value (r=0.854, 0.804, 0.078 and 0.082, respectively), and is negatively correlated with total N (r=−0.201,
−0.529, −0.221 and −0.821, respectively), total P (r=−0.143, −0.213, −0.362 and −0.751, respectively) and available P (r=−0.339,
−0.351, −0.576, and −0.676, respectively). Sucrase, urease and alkaline phosphatase are negatively correlated with the pH
value, while positively correlated with the other fertilizers (r ≈ 1). The authors suggest that enzyme activity will be a
great potential as an indicator of soil quality. |
