American Black Walnut Cultivation
U.S. Black Walnut is a fruit and fruit-used tree species that can be used as an excellent home material and plywood. Its nucleolus is an important ingredient for making ice cream, cakes, and sweets. In 1996, the country listed the American Black Walnut as the first batch of key introduction projects, and established provenance variety experimental areas in Shanxi, Beijing, Henan, etc. After three years of experiments, it was initially successful, and it is expected to become the “Three North†region in China. Important hard-leaved species in the South Central and Southwest Highlands. First, the United States black walnut cultivation techniques Site conditions 1 soil. It can grow normally in silt, loam, clay loam and sand clay. The coarse sand and gravel layer soil should not be developed; 2 the thickness of the soil layer. Black walnut is the main root, and the soil thickness in the cultivation area should not be less than 100 cm. 3 Soil drainage. Soils with good drainage and pH greater than 4 and less than 8 should be selected for planting. 2. Planting density and seedlings were not planted 1 forestry intercropping agricultural forest. Usually 3 meters 3 meters, 4 meters 4 meters. 2 timber forest. Should be based on the size of the planting seedlings, timely thinning. The density is generally 3 meters 3 meters, 4 meters 4 meters, 4 meters 6 meters, 5 meters 6 meters and so on. The density can be determined based on the DBH. There is a formula: average row spacing (m) = (average breast diameter (cm)/2.52+8) 3.28. Seedlings should be planted with one-year-old seedlings. According to the biological characteristics of black walnuts, digging large pits for planting, 80 cm x 80 cm pits are appropriate, and the main root is trimmed to about 25 cm. Afforestation time is generally in the fall. Second, the grafting method of black walnut grafting black walnut can be roughly divided into double-tongue joints, spliced ​​joints, lateral joints, bud grafted grafted grafts and mature trees, and several other methods, the operation method and walnut grafting are basically the same, the following mainly introduces the high Then. 1. Seedlings of the rootstock selection tree species can choose real walnut seedlings, maple, walnut seedlings and other tree species, more than 10 years old, more than 10 centimeters of breast diameter of a tree with strong tree potential changed. 2. The scion collection and preservation are collected about 20-30 days before the scion germination, and can also be collected after the fall. The thickness is 0.8-1.5 cm, and the shoots are full, the branches are full, there is no pests and diseases, and the cuts are followed by the closure. The scion is stored in a cellar below 5 meters in the shade or in a cold room at 0-3 degrees Celsius. 3. Grafting time is best when the length of local walnut tree shoots is 1-3 cm. 4. The grafting method uses the skin graft tongue to connect the high graft. 1 Rootstock processing. Select the trunk 130 cm smooth place, will be cut off the top, and then cut the cut ends, in order to change the junction to cut a 2-3 cm crescent-shaped incision, and the rootstock old skin vertical to tender skin, noodles long 8-10 cm. 2 scion clipping. The stored cuttings were cut into 15-18 cm long scions, leaving 2-8 full-filled buds on the top, 1.5 cm from the upper end of the cut, and a 5-8 cm long, horse-shaped cut at the lower end. To smooth. 3 grafted. The skin of the scion's ear was gently lifted off the xylem, and the xylem of the scion was inserted in the middle of the cut rootstock crescent and the scion was covered on the tender skin of the rootstock. 5. After the lashings are properly connected, they are tied tightly with hemp rope or plastic rope and coated with a diluted 2% water retention agent. Finally put on the newspaper tube filled with wet soil, and then put on a plastic bag to complete. Water should be discharged in time so as not to affect the survival rate of grafting. 6. After the management 1 When the buds germinate, promptly remove the buds on the rootstock, so as not to affect the growth of the scion. 2 To release the air in time, the scion can be sprouted after about 20 days. When the new shoot grows to the top of the plastic bag, it can open a small mouth at the top so that the tips of the tender shoots will naturally extend and the air outlet should be opened gradually from small to large. . Must not let go, to avoid the new shoots do not adapt to the external environment and cause death. 3 loosen. Two to three months later, the lashing ropes were loosened once and removed after 8-9 months. 4 Timely establishment of pillars to prevent wind breaks. After several years of experiments, black walnuts were grafted onto walnut rootstocks with good affinity and a high survival rate of over 95%. However, after 3 years, the grafted interface was significantly enlarged, forming a tumor, and the phenomenon of small feet was extremely serious. China Agricultural Network Editor