| The Loess Plateau in northern Shaanxi is affected by the continental monsoon climate.The uneven spatial and temporal distribution of rainfall has caused more droughts in spring and erosion caused by heavy rain in summer.These reasons have restricted the development of the apple industry in the region.In order to meet the demand for water resources in the northward expansion of the apple planting area and the expansion of the planting area,this experiment will increase the water use efficiency and irrigation water production efficiency of apple orchards in the area as the goal.In Qingshuigou Village,Huainingwan Town,Zizhou County,experiments on orchard coverage combined irrigation were carried out.The experiment set two variables:(straw mulching SM,ground fabric mulching FM,clear tillage control CK)and irrigation volume(high water treatment W1 is100% irrigation volume to achieve 85% field capacity,medium water treatment W2 is 75%irrigation volume to achieve 85% field capacity,low water treatment W3 is 50% irrigation volume to achieve 85% field capacity)two variables.In this paper,through comprehensive analysis of meteorological data,soil moisture content,ground temperature,physiological indicators of fruit tree growth,fruit quality and yield,and comparison of water use efficiency and other indicators,the high water treatment under straw mulching is adapted to the local mulching irrigation mode.The main results are as follows:(1)Mulching and irrigation treatments have a significant effect on the growth index of fruit trees such as the new shoot length.The horizontal and vertical diameters,volume,number of fruit per plant,yield and irrigation of apples showed positive correlation.The new shoot length of fruit trees,SPAD,leaf area index,apple volume and other indicators present a "fast-slow-fast" S-shaped growth process,which can be fitted by the logistic curve model,which can better describe the growth process of growth indicators.(2)Under the same irrigation amount,the soil moisture under the straw cover> the soil moisture under the ground fabic mulching> the soil moisture in clear tillage control.The curve of soil moisture content increasing with vertical depth shows a "low-high-low" trend.Straw and ground fabric mulching can significantly increase soil moisture content,straw mulching can reduce ground temperature,and ground fabric mulching will increase ground temperature.Increased irrigation volume can play a role in lowering ground temperature,and it can also reduce the daily variation of ground temperature.The heat preservation effect of the ground fabric mulching is the strongest,and the time of the highest daily temperature is delayed compared with the straw mulch and clearing control.(3)Mulching can increase the root density of apple trees.The root length density at different radial distances changes "exponentially" with depth.The root length density decreases with increasing distance from the fruit tree in the horizontal ground direction,and in the vertical direction,except for the ground fabric mulching,the root length density increases first and then decreases.Irrigation volume increased,root density increased.The influence area of water treatment on root length density is 0-0.4m horizontally and 0-60 cm vertically.(4)With the increase of irrigation volume,the fruit yield of straw and ground fabric mulching and the clear tillage control group increased.The horizontal and vertical diameters and fruit volume of apples covered by the ground cloth increased the most.The excellent fruit rate(> 75mm),soluble solids,sugar-acid ratio under the ground cloth are the best,and the taste is the best.The fruit covered with straw has the highest yield,and the water use efficiency and irrigation water production efficiency have reached the maximum,but the yield of the ground fabric mulching has no significant difference from the maximum.By comprehensively evaluating economic indicators through the CRITIC method,SMW1 has the highest overall score. |
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