Suggestions on Soil and Water Conservation Engineering in Walnut Garden

When    builds walnut orchards in mountainous and hilly areas with dry morning and little rain and barren soil layer, it can lead to the destruction of original vegetation and unreasonable farming, which can easily lead to soil and water loss. Especially in the rainy season, the surface runoff caused by excessive precipitation washes away the surface fertile soil and organic matter, which not only thinns the soil layer of the orchard, increases the stone content, decreases the soil fertility, exposes the walnut root system, weakens the tree potential, reduces the yield, shortens the life span, and even causes debris flow or large area landslide, endangering the safety of the walnut orchard. Therefore, soil preparation and soil and water conservation projects must be built at the beginning of the garden to improve the soil condition and improve the drought resistance of trees. There are several common ways of soil and water conservation projects.

   1. The terrace surface of terraced fields is flat, which is beneficial to farming, improves the site conditions of walnut, makes full use of the rich light and heat resources in hilly and mountainous areas, and creates an ideal small ecological environment for walnut. Through the construction of terraces, the slope can be changed into terraces of different sizes, the slope can be slowed down, the catchment surface can be reduced, the runoff can be reduced, the soil erosion can be effectively prevented, the soil water and fertilizer conservation capacity can be effectively enhanced, the air temperature on the planting surface and the accumulated temperature in the growing season can be increased, and the occurrence of walnut freezing injury can be reduced.

   terraces have the characteristics of equal height trend, which is convenient for soil improvement and intensive cultivation, and also creates conditions for the establishment of drainage and irrigation system and mechanical management. The terraced surface of the mountain walnut orchard can not be absolutely horizontal in order to discharge too much water. In the areas with abundant precipitation and deep soil layer, the inner oblique terrace can be designed; in the areas with less precipitation and shallow soil layer, the outer oblique terrace can be designed to adjust the water distribution of the terrace and is beneficial to soil improvement.

   2.Contour trench is a simple soil and water conservation method adopted in the hilly and mountainous areas of northern China, which is suitable for areas with gentle slope and less rainfall. The trench method is: on the basis of the measurement along the contour line, dig the trench along the contour line at a certain distance, and put the soil on the outer edge of the trench to build a trench, so that the trench section and the outer edge section are continuous into a positive and negative arc. Walnuts are planted on the outer slope of the trenches, and in the trenches, an earth dam can be built at regular intervals to hold Rain Water and prevent soil erosion. Because the soil layer of the trench is thicker and there is more water next to the trench, the young trees grow and develop well, but the trench increases the slope in the trench and the outer edge of the trench, which makes the slope between the two trenches steeper than the original slope, which enhances the possibility of soil erosion between the two trenches. Through contouring trenches, changing long slopes into short slopes, and changing Rain Water direct current into crosscurrent, such as artificially planting grass or dwarf crops at the top of the trench, between tree rows and in ditches, a better effect of soil and water conservation can be achieved. Trenches have the functions of weakening surface runoff, storing water and soil, ripening soil, and so on. After farming for a period of time, according to the specific conditions, the trenches will be gradually transformed into compound terraces to facilitate the normal growth of walnuts and prevent Rain Water from scouring.

   3. The soil and water conservation project of Yulingkeng slope can be excavated in different ways according to the slope. Trenches can be raised at the slope of 5 °~ 15 °, terraced fields can be built above 15 °, and fish scale pit can be dug when the slope is more than 25 °. The fish scale pit can be arranged according to the zigzag shape, and the semicircular pit is excavated along the contour line, and the outer ridge is cultivated with stone or core soil, with a ridge height of 30cm, a pit depth of more than 1 meter and a diameter of 2 meters. the pit distance is determined according to the planting density requirements, and the topsoil and core soil are stacked respectively. There is a small trench in the left and right corner of the pit to attract and store runoff. When filling the pit, all the topsoil on the slope is backfilled, and the pit is inclined inwardly, and the walnut tree is planted on the outside of the pit, and then, with the growth of the walnut tree, the outer edge of the soil is increased year by year to make it gradually transition into a small slope terrace.

   4. Across the slope, the horizontal ditch of storing runoff is 13 °~ 30 °, and the slope is delineated along the contour line with a distance of 60.7 meters. A ditch with a width of 1 meter and a depth of 80 centimeters is excavated along the line in autumn. When opening the ditch, the topsoil layer is placed above the slope with a thickness of 20 centimeters, and the raw soil below 20 centimeters in the ditch is dug out to dig out the lower barrier ridge, and the upturned mature soil together with the slope topsoil is mixed with organic fertilizer to backfill the ditch, and the horizontal ditch extending along the contour line is formed into a horizontal ditch with a solid outer ridge and a ridge height of 30 centimeters in order to store water. The horizontal earth retaining dam is made at a certain distance in the ditch to prevent Rain Water from flowing along the ditch after rainfall catchment, so that the water distribution in the ditch is uniform.

   is 0. 5% higher than normal. The 3-meter horizontal ditch can ensure the safe catchment of slope runoff and prevent soil erosion. If this method is combined with biological measures such as growing grass on the ridge, the ecological benefit of preventing soil erosion will be better.