Effect Of Natural Weeds On Fuji Apple Orchard In Arid Desert Area

Apples are the main cultivated fruit trees in Xinjiang's southern Xinjiang basin.However,Xinjiang's southern Xinjiang is dry and rainy,and the soil is barren.For a long time,the clearing system has made the orchard soil's ability to retain fertilizer and water poor,which in turn affects fruit quality and yield.In this study,the grassland area and the clear cultivation area were used as test points to compare the differences in microclimate factors,soil physical and chemical properties,photosynthetic characteristics,leaf quality,and fruit quality of apples between the grass area and the clear cultivation area.Grey correlation analysis,regression analysis,path analysis,and fuzzy comprehensive evaluation methods were conducted on apple canopy microclimate,soil physical and chemical indicators,main photosynthetic and limiting factors of net photosynthetic rate,apple fruit quality,etc.The purpose of this analysis is to reveal the impact of natural grass on improving the ecological environment of the orchard and improving the quality of the fruit,and to provide a certain theoretical basis and technical guidance for soil management in the apple orchard.The main research results obtained are as follows:?1?The cooling effect of natural grass on the lower and middle layers of the apple canopy is better than that of the upper layer,and the moisturizing effect on the lower layer and the ability to weaken the light intensity are better than the middle and upper layers;natural grass reduces the ground temperature of each soil layer of the orchard The cooling effect weakens as the soil depth increases.The comprehensive evaluation of the canopy microclimate shows that natural grass improves the microclimate environment of each apple canopy,and its regulating effect weakens as the apple canopy height increases.?2?Natural grass reduces the pH,conductivity,bulk density and water-soluble salt content of the orchard soil,and increases the organic matter,available nitrogen,available phosphorus,available potassium,total nitrogen,total phosphorus and total potassium content of the orchard soil.The shallower the soil layer,the longer the grass growing period,the more obvious the effect.Natural grass increases the water content,total porosity,aeration porosity,water-holding porosity and the Zn,Mn,Fe content of the 0-20cm soil layer in the orchard soil at various stages.The grey correlation analysis of the physical and chemical properties of the soil shows that the improvement effect of natural grass on each layer of orchard soil is greater than that of the clear cultivation area,and its improvement effect decreases with the increase of the soil depth.Regression analysis of soil physical properties on organic matter shows that within a certain range of soil layers,the pH,water content,and bulk density of the orchard soil increase with the depth of the soil layer,and the total porosity,electrical conductivity,and water-soluble salt content all increase with the soil.As the layer depth increases,it decreases.?3?Natural grass increased Pn,Gs,WUE and LUE of apple leaves,and reduced intercellular CO₂concentration?Ci?and transpiration rate?Tr?.Path analysis found that the temperature?Ta?of clearing treatment has a limiting effect on Pn,Gs,Ci,Tr and relative humidity?RH?are the main determinants of Pn;the natural grass treatment Ta and RH have a limiting effect on Pn,Gs,Ci and Tr are the main determinants of Pn.?4?Natural grass improves the quality of apple leaves.The length,width,area,thickness,fresh weight,dry weight and specific weight of apple leaves increase significantly;it promotes the chlorophyll synthesis of apple leaves and apple leaves The content of chlorophyll a,chlorophyll b,carotenoids and total chlorophyll increased significantly,and the chlorophyll SPAD value increased significantly;the content of nutrients and mineral elements in apple leaves was increased,and the total nitrogen,total potassium and Ca,Mg,Cu,The B content increased significantly.?5?Natural grass improves the appearance quality of apples.The single fruit weight,fruit hardness,coloring rate and coloring index of apples increase obviously;improve the internal quality of apples,the content of soluble protein,vitamin C and sugar-acid ratio of apples Increased,the titratable acid content decreased;changed the anthocyanin and chlorophyll content of the peel and pulp,the anthocyanin content of the peel and pulp increased significantly,chlorophyll a,chlorophyll b,total chlorophyll content were significantly reduced.Comprehensive evaluation of apple quality traits shows that natural grass can significantly improve the overall quality of apple fruit.