Effects Of Simulated Warming On Soil Properties And Soil Enzyme Activities Of Pinus Tabulaeformis Forest In Daqingshan Mountains

Enzyme system is the most active part of soil.Soil enzymes are involved in the circulation and transformation of soil materials and play a role in promoting soil metabolism.With the global climate change,greenhouse gases are getting higher and higher,and soil enzyme activity and soil physical and chemical properties are affected.Therefore,the study on the response of soil enzyme activities in active layer to warming can provide a theoretical basis for predicting the response direction of soil enzymes at different depths to climate warming in Daqingshan,Inner Mongolia.In this experiment,the effects of temperature increase on soil physical and chemical properties and soil enzyme activity were studied by simulated warming test of Pinus tabulaeformis forest in Daqingshan,Inner Mongolia.The results are as follows:（1）Through warming treatment,0-10 cm soil temperature increased by an average of 1.22°C,10-20 cm soil temperature increased by an average of0.99°C.The humidity of 0-10 cm soil layer decreased by 6.09%.The humidity of 10-20 cm soil layer decreased by 4.55%.Soil p H changes between8.20-8.32,basically alkaline soil.Warming reduced the total nitrogen content and nitrate nitrogen content as a whole;increased soil p H,total phosphorus content.（2）From the vertical spatial distribution of soil,with the increase of soil depth,the activities of soil invertase,soil amylase,soil urease,soil protease,soil alkaline phosphatase and soil catalase decreased.The simulated warming experiment significantly affected soil enzyme activity,and the changes of soil enzyme activity were also different under different soil layers and different treatments.In 0-10 cm soil layer,warming increased soil amylase activity,soil protease activity,soil alkaline phosphatase activity and soil catalase activity.The soil urease activity decreased as a whole.In the 10-20 cm soil layer,warming increased soil amylase activity and catalase activity as a whole.（3）According to the results of soil enzyme stoichiometry,C:N_EEAratio is greater than C:P_EEAratio is greater than N:P_EEAratio.The length of soil enzyme vector is relatively concentrated,and the range of variation is1.12-1.23.The vector angle of soil enzymes was greater than 45°,indicating that soil nutrients were limited by P.In the 0-10 cm soil layer and 10-20 cm soil layer,the vector length was significantly negatively correlated with soil alkaline phosphatase and significantly positively correlated with C:P_EEA.The vector angle was significantly positively correlated with soil alkaline phosphatase and significantly negatively correlated with C:P_EEA.Vector length and vector angle also had significant or extremely significant correlation with individual treatments and individual soil layers of C:P_EEA.（4）Under different treatments in different soil layers,the correlation between soil physical and chemical properties and soil enzyme activity and soil enzyme activity stoichiometry was significantly correlated or extremely significantly correlated.The vector length and vector angle of soil enzyme were only significantly correlated with soil total phosphorus content and p H in individual soil layers.