Changes In Soil Nutrient And Enzyme Activity Of Apple/White Clover Compound System

Orchard grass cultivation is a sustainable and efficient orchard soil management model.It is also an orchard soil management model popularized by developed countries such as Europe,America and Japan,and it has been promoted as an ecological orchard construction technology measure in China.At present,the research on grass cultivation in orchards mainly focuses on the research on the effects of grass in the orchard,and the research on the interaction mechanism of the grass orchard compound system is relatively weak.In this study,apple(Malus demestica Borkh.)and white clover(Trifolium repens L.)were used as test materials,and the apple/white clover compound system was used as the research object.Dynamic,continuous and quantitative research methods were applied to different fruit trees.The soil nutrients and enzyme activities of the apple/white clover compound system were determined during the growth period,and the spatio-temporal changes of soil nutrients and enzyme activities in the composite system were analyzed.The relationship between soil nutrients and fruit tree nutrient in the apple/white clover compound system was discussed.In order to reveal the absorption of soil nutrients and the mechanism of soil-feedback and the management of the orchard compound system in the orchard compound system,the main research results are as follows:1.The content of water-soluble organic carbon in the spring and slightly autumn growing seasons of fruit trees was as follows: intercropping white cloverleaf treatment <fruit trees monoculture treatment,but the content of water-soluble organic carbon in the deciduous period of fruit trees showed white cloverleaf treatment.> The monoculture treatment of fruit trees is mainly performed in the 0-30 cm soil layer;in the different growth stages of fruit trees,the effect of intercropping white clover treatment on the water-soluble organic carbon in the apple/white trifoliate system is mainly in the grass area.2.In the different growth stages of fruit trees,the soil available phosphorus showed intercropping white clover <fruit trees alone,mainly in the 0-20 cm soil layer;in the spring shoot growth and defoliation period,the soil available potassium showed intercropping white clover < fruit trees alone However,in the autumn shoot growth period,there was no significant difference between the intercropping white clover and fruit trees;in the spring shoot growth and deciduous period,the soil nitrate-nitrogen showed an intercropping white clover,and the fruit trees worked monolithically,but during the autumn shoot growth period.For the intercropping white clover>fruit tree monocropping,the content of nitrate nitrogen in 0-20 cm soil layer can be significantly increased.In the spring shoot growth and deciduous period of fruit trees,the content of ammonium nitrogen in the soil shows intercropping white clover>fruit tree monocropping.During the autumn shoot growth and deciduous growth of fruit trees,the main area of action of white clover leaf treatment on ammonium nitrate nitrogen was grass growing area.3.The results of geostatistical analysis showed that the treatment of white clover could change the spatial variability and correlation of soil nutrients during different growth periods of fruit trees.Intercropping white clover can increase the spatial variability of soil ammonium nitrate,available phosphorus and available potassium during the growth period.White clover treatment during the growth of autumn shoots can increase the spatial variability of nitrogen,phosphorus and potassium nutrients in the compound system.The treatment of white clover during sexual and deciduous periods reduced the spatial correlation of ammonium nitrogen,available phosphorus and available potassium,and increased the spatial correlation between nitrate nitrogen and WSOC.Intercropping white clover was used to treat the non-soil area of the grass area.Nutrient changes are even stronger.4.Soil urease activity in different growth stages of fruit trees in the 0-40 cm soil layer showed intercropping of white clover and fruit trees,but there was no significant difference in all soil layers.The activities of soil sucrase in different growth stages of fruit trees showed that Intercropping white clover> fruit tree monocropping,in which the activity of sucrase in soil treated with white clover leaves in deciduous period was significantly higher than that in fruit trees;the activity of alkaline phosphatase in the vertical direction of fruit trees showed intercropping white clover>fruit tree monocropping,in the autumn shoot and deciduous period,intercropping white clover <fruit tree monocropping,but no significant difference in all soil layers;apple/white clover compound soil sucrose,urease and alkaline phosphate The activity of the enzyme showed that the grass area was significantly higher than the non-rooting area;Correlation analysis showed that soil urease activity was significantly positively correlated with water-soluble organic carbon,available N and P,and negatively correlated with available K.There is a very significant correlation between fast-acting N,P,and K.5.In the different growth stages of fruit trees,the N,P and K contents of apple leaves in the composite system were lower than those of fruit trees alone,compared with monocropping fruit trees.The potassium content in the leaves decreased most during the growth period of spring shoots,and the growth of autumn shoots was the highest.The leaf nitrogen and phosphorus content decreased significantly during the deciduous period;Correlation analysis showed that leaf total phosphorus,total potassium and total nitrogen were negatively correlated with soil WSOC and available phosphorus and nitrogen;total potassium and total phosphorus in leaves and soil available potassium.There was a positive correlation with nitrate nitrogen,and there was a weak correlation between total phosphorus in leaves and available potassium and available nitrogen in soil.