The horizontal distribution range of walnuts in China: from Mengla County, Yunnan Province, 2108 ′ 32 "north latitude to Bole County, Xinjiang, 44 54 ′ north latitude, with a longitude of 23 25 ′; It starts in Tashkurgan, Xinjiang, with an east longitude of 7515' and ends in Dandong, Liaoning, with an east longitude of124 21',spanning 49 06'.
Walnut trees have strong adaptability, few pests and diseases, labor-saving management, convenient storage and transportation of fruits and long service life. Walnut trees like warm and light, and have strict requirements on water, especially in the new shoot growth period and fruit development period, which need sufficient water supply, so they should be planted in sandy loam with loose structure, water retention and good ventilation. The growth cycle of walnut is divided into germination stage, leaf spreading stage, flowering stage, fruit hard core stage and fruit maturity stage.
Fertilize soil or land
Lime should be applied before planting acid soil, and pay attention to the deep turning of the soil or the deep turning of the tree tray, so as to facilitate the early fruiting, high and stable yield of young trees. The fertilization amount of walnut is: 1 ~ 2-year-old young trees, N 0. 1kg per year, and appropriate application of P K fertilizer according to soil content; Manure 150 ~ 250 kg was applied to adult tree-based plants. Phosphate fertilizer 1.5 ~ 2.5-5 kg, ash fertilizer 2.5 ~ 5 kg. Topdressing 2 ~ 3 times a year (before germination, after flowering and during fruit hard core stage), and applying nitrogen fertilizer 1 ~ 2.5 kg per plant.
1, base fertilizer. The base fertilizer should be applied as soon as possible and should be completed after harvest and before defoliation. Each adult tree should be applied with high-quality organic fertilizer 100 ~ 200 kg.
2. Top dressing. The suitable period of topdressing is three stages: before flowering, young fruit expansion and fruit hard core. Generally, 0.8 ~ 1 kg of nitrogenous phosphate fertilizer is applied to each plant every time.
3. Spraying fertilizer on the leaves. Fertilization period is flowering period, new shoot growth period, flower bud differentiation period and after harvest. Commonly used fertilizer spraying types are 0. 1% ~ 0.2% boric acid, 0.5% ~ 1% ammonium molybdate and 0.3% ~ 0.4% copper sulfate.
grow seedlings
Grafting propagation is the main method. Rootstock uses this rootstock or 1 ~ 2-year-old walnut seedlings. First, the seed sand bank was layered for more than 60 days, then it was taken out and planted in spring. The row spacing of drilling is 30 ~ 40cm, the plant spacing is12 ~15cm, and the covering soil is about 5cm. When sowing, the suture line of the seed is perpendicular to the ground, which is beneficial to the smooth growth of radicle and bud. The suitable time for branch grafting is between beginning of spring and rainy season, and the best time is when the juice begins to flow out and the top bud of the rootstock has germinated. The suitable time for bud grafting is around the vernal equinox, when the rootstock begins to sprout, the top bud spreads its leaves, and the bark is easy to peel off. The grafting interface and scion were covered with plastic bags and wrapped with wet sawdust for insulation. The grafting survival rate was over 95%. Grafting of walnut cotyledon seedlings. When the seed buds will expose the true leaves, cut off the rootstock buds on the petiole 1 cm, and then put them into a healing pool or a simple greenhouse. After survival, the survival rate can reach more than 80%, which can shorten the seedling raising time.
Carya illinoensis seedlings can also be cutted. The roots of 1-4-year-old seedlings with the thickness of1and 5cm were selected and cut into 1O cm, and the survival rate could reach 90% ~ 100% in winter and spring. It can also be propagated by tillering, layering, cutting and grafting. Walnut has few lateral roots, so the main roots should be cut off at seedling stage to promote lateral roots and improve the survival rate of planting. The planting density is 2 10 ~ 285 plants /hm ㎡. It can be planted in spring and autumn. Because walnut flowers are dioecious and need cross-pollination, pollination trees should be configured.
disease
anthrax
Walnut branch blight: This disease is mycosis. It mainly harms the branches and causes them to die. Common planting
The damage rate of trees is about 20%, and the serious damage rate can reach 90%. This disease mainly affects the growth and yield of trees.
The symptom of the disease is that after the 1-2-year-old branches are damaged, they gradually dry from the top to the trunk, and the leaves turn yellow and fall off. Dense black spots are produced on the dead branches, and mucus flows out when the humidity is high, forming black tumor-like protrusions. Bacteria overwinter on diseased branches and invade through wounds, only hurting weak trees.