Study of soil enzymes activity and their correlation with soil nutrients in different types of saline-alkali soils in Yinchuan Plain of Ningxia

Soil enzyme activities,its seasonal changes and the relationship between soil enzyme activities and soil nutrients of different types of saline-alkali soil in Yinchuan Plain of Ningxia were studied by colorimetry,titration and conventional determination.The results showed that soil catalase,invertase,alkaline phosphatase,and urease activity showed a decreasing trend(p 0.01) with the pH value and total salt content increasing in saline-alkali soil.The soil alkaline phosphatase activity in alkali soil was significantly higher than that in salinization soil,the catalase,invertase and urease activity were not significant difference among the different types soil.Soil enzyme activity had significant seasonal changes in 0-20cm soil depth,such as alkaline phosphatase activity of alkaline soil,catalase activity of salinization soil performed August June September;invertase activity in alkaline and salinization soil,urease activity in alkalization soil,alkaline phosphatase activity in salinity soil showed enzyme activity seasonal variation September August June.They had a good positive correlation between soilcatalase,invertase,alkaline phosphatase,urease activity and soil organic matter,total nitrogen,total phosphorus,total phosphorus,total potassium,available nitrogen,available potassium in sali-alkalization soil.