Synergistic and inhibitory effects of soil enzymes along desertified gradients of the Zoige alpine meadow

Desertification resulting from intensive human activities and climate change has become increasingly severe. Consequently, it is important to study soil physical and chemical properties and enzyme activity for the protection and restoration of grassland ecosystems. In this study, we observed plant community characteristics and analyzed soil physical and chemical properties and enzyme activities along a transect (from more to less degraded) in the Zoige alpine meadow ecosystem. As the degree of degradation increased, the soil bulk density, pH and the alkaline phosphatase (S-ALP) activity also increased, while soil organic carbon, total carbon, available nitrogen, total nitrogen, available nitrogen, total phosphorus, and activities of urease (S-UE), lignin peroxidase (S-Lip), β-glucosidase (S-β-GC) and N-acetyl-β-D-glucosidase (S-NAG) decreased. Soil pH was positively correlated with S-ALP (P<0.01), and negatively correlated with S-Lip, S-β-GC and (S-NAG) (P<0.01). S-ALP was negatively and linearly correlated with S-Lip (P< 0.01, R²=0.27) and S-β-GC (P< 0.05, R²=0.17), indicating that increased S-ALP activity has some inhibitory effect on S-Lip and S-β-GC. Moreover, S-Lip was positively and linearly correlated with S-β-GC (P<0.01, R²=0.59) and S-NAG(P<0.01, R²=0.26), suggesting that S-Lip could promote S-β-GC and S-NAG activities. The findings provide a scientific basis and important reference for further exploration of the dynamics of soil enzyme activity in grassland desertification, Zoige region.