Characteristics and Correlation Analysis of Soil Nutrient and Enzyme Activities of the Middle Yellow River Wetland

The effects of different land use patterns(wetland,natural meadow,cultivated land,saline-alkali land) on soil nutrient(organic matter,N,P,K) and enzyme activities(urease,invertase,catalase,alkaline phosphatase) in wetland degradation were studied for the Yellow River wetland of Shaanxi using field sampling and indoor analysis.Results indicated that soil nutrient and soil enzyme activities had significant differences among different land use patterns(P0.01).The order was natural meadowcultivated landwetlandsaline-alkali land.Soil organic matter and soil nutrients of cultivated land fell between that of natural meadow and wetland,but saline-alkali land was far below that of natural meadow and wetland by 3.4% and 6.9%,indicating that over-exploitation of land resources will seriously affect soil fertility and lead to soil degradation.Enzyme activities were significantly correlated with soil organic matter and soil nutrient,and between soil enzyme activities themselves.The activities of urease,invertase,catalase,alkaline phosphatase were significantly different under diverse land use patterns(P0.01),varied in the same order as that of soil nutrient.Soil enzyme activities could indicate the level of soil fertility,and could be used as an index for soil fertility evaluation of wetlands.