Walnut trees like light and have developed roots, so they need good ventilation in the land. Therefore, the place where walnut trees are planted should choose a place with sufficient light, shelter from the wind and sun. Dense planting garden or forest-grain intercropping should choose the zone with flat terrain, complete shelter forest and light wind damage; On the land, sandy loam and loam with a land thickness greater than 1m should be selected, which are fertile, breathable and well drained, and special attention should be paid to the salt content of the land not exceeding 0.25%; With good water quality and irrigation conditions.
Second, choose good varieties.
Excellent varieties are the material basis for high-quality and efficient planting, and varieties must be strictly selected according to the natural conditions in Wuwei. Adhere to the combination of local varieties and imported varieties, and the excellent varieties suitable for planting in Wuwei are mainly Wuwei Bopi and Wuwei, Xinjiang varieties Wen 185, Xin No.2, Zha 343, Liaohe series varieties and Jinlong series varieties. Among them, Wuwei local varieties, Zha343 and Jinlong series varieties are late-fruiting varieties with high crown, late fruiting and long life. Wen 185, Xin 2 Liaohe series 1, 3 are varieties with small crown and early fruit.
Third, variety collocation
Walnut is a dioecious tree species, and most of the same plant naturally has different male and female flowering periods, which requires pollination by different plants. Therefore, attention should be paid to the configuration of pollinated varieties in production, and it is best to choose varieties that can pollinate each other for cultivation. For example, the main varieties planted in the garden with a single variety are equipped with one row of pollinated varieties every 6- 10. Zha343 is one of the pollinated varieties, with large amount of pollen, long flowering period, high yield and excellent quality.
Fourth, select grafted seedlings for field planting and reasonable close planting.
Grafted seedlings have the advantages of early fruiting, neat fruits, consistent maturity, pure varieties and rapid early yield increase. Therefore, when building a garden, we must choose pure grafted seedlings, and it is best to choose local walnuts as rootstocks to graft seedlings cultivated by excellent varieties. Planting density depends on varieties and cultivation methods. Early-bearing varieties have small crown and early fruit, which are suitable for close planting. When planting in patches or intercropping, the density of 2 1-55 plants should be 3-4× 4-8 meters to improve the early yield. Late-maturing varieties have large crown, late fruiting and lower planting density. Generally, it is better to choose 5 ~ 7× 8- 10 meter to keep a long income period.
V. High standard colonization
Before planting, according to the plant spacing point alignment, dig a planting hole with a length of 80cm or a planting ditch with a width of 80cm, preferably in autumn and spring, so that the soil in the hole and ditch will be weathered for a long time. If the soil is sticky or shallow, planting holes should be added, and exotic soil, cinder, chemical fertilizer or backfill topsoil should be used to improve the soil texture and create good growth conditions for root growth. After digging the planting holes, backfill the topsoil with organic fertilizer and chemical fertilizer, and apply high-quality organic fertilizer (farmyard manure) 15-20kg and phosphate fertilizer 1-2kg to each hole. When the fertilizer is insufficient, 30cm thick rotten stalks and leaves can be placed on the pit surface, and 20cm thick topsoil can be filled on them for planting.
VI. Management of Soil, Fertilizer and Water
1, soil management: 1) Deep ploughing and soil improvement: after harvesting fruits every year or every other year, dig a semicircular or circular ditch with a width of 50cm and a depth of 60-80 cm around the crown along the vertical projection edge of the crown, then put the mixed organic fertilizers such as base fertilizer, green manure and straw at the bottom of the ditch, put the subsoil on the surface, and finally pour it thoroughly with big water. 2) intertillage: combine irrigation and weeding in spring, summer and autumn, intertillage for 3-5 times, and the depth is 10- 15 cm. 3) Reasonable intercropping: wheat, corn and other field crops can be intercropped with large row spacing, and summer sowing crops such as vegetables and green manure should be selected for medium-density gardens. When intercropping, it is required to leave 60-80 cm open space around or on both sides of young walnut trees as a nutrient zone to protect and promote their growth.
2. Scientific fertilization: Walnut trees like fertilization, and with the increase of tree age, the amount of fertilization increases year by year. ① Young trees (1-3 years), each plant is applied with 50 grams of nitrogen fertilizer, 20 grams of phosphorus and potassium fertilizer (all effective components) and 50 kilograms of organic fertilizer every year; For 4-6-year-old trees, nitrogen fertilizer 100g, phosphorus and potassium fertilizer 40g and organic fertilizer 50kg should be applied to each tree. ② Apply 200-400g of nitrogen fertilizer, 0/00-200 g of phosphorus and potassium fertilizer and 50-/0/00 kg of high-quality organic fertilizer to each first-bearing tree every year. ③ In the full fruit stage, 800- 1200g of nitrogen fertilizer, 600- 1000g of phosphorus and potassium fertilizer and 0/00-300kg of high-quality organic fertilizer were applied to each plant every year. (4) After the fruit is harvested in autumn, base fertilizer should be applied with hole enlargement and deep ploughing. Topdressing should be applied in 2-3 times. Before the female flower opens, before the fruit expands after the flower, and after the hard core, the amount of fertilization for 3 times accounts for more than 70% of the total. Top dressing outside the roots for 3-4 times during the growth period, such as urea, potassium dihydrogen phosphate, ferrous sulfate, etc. Generally used for spraying, especially in the later crown.
3. Reasonable irrigation: the newly planted walnut orchard should be irrigated immediately after planting, and then irrigated in time according to the soil moisture status. Generally, there are three key waters to be irrigated during the growth period, namely, water before flowering, water after fruit swelling and hard core water. Before the soil freezes, water should be watered early in winter, and after watering, the trees should be plowed and raked to keep moisture and raise the ground temperature.
Seven, plastic pruning
Walnut tree should be sparse, natural, easy to cultivate, with many branches, large crown, many fruiting parts, high yield and long economic life. Sparse the tree with 5-7 main branches arranged in 2-3 layers, control the height of the tree at 3-5 meters, and control the lateral branches of the whole tree at 15-25. There is no central trunk in the happy shape of nature. The whole tree has 2-3 main branches, 2-3 lateral branches are selected from each main branch, and there are 1-2 secondary lateral branches on the lateral branches. The height of the tree is controlled at 3-5 meters. After the completion of tree cultivation, it is mainly to retract the drooping branches in time, pay attention to raising the angle of branches, inhibit their vain growth, and promote the formation of fruiting mother branches; Selecting indoor strong branches that have been placed for a long time, thinning the surrounding weak branches, and retracting after branching, so as to promote lateral growth, increase the number of branches, expand the fruiting area, and carry out branch group culture, so that large and medium branches are evenly distributed in the crown, and the spacing between branches is suitable for 60-80 cm; For the aged branches after fruiting, we should pay attention to selecting and retaining the spare branches with space at the lower part, and update the aged branches in time to prevent the fruiting parts from moving out.
Eight, young trees wintering protection
Young walnut trees have weak cold resistance and are easy to be frozen in open winter, so young trees under 4 years old must take protective wintering measures. The 1-2-year-old tree with a trunk less than 3cm can be directly covered with soil to protect it from wintering. For 3-4-year-old young trees with trunk more than 3cm, the method of piling soil at the bottom and bagging at the upper part should be adopted. The pile of soil at the basement and the fill in the bag should be compacted to prevent freezing and thawing collapse. Thick trees that cannot be buried or exposed are wrapped with plastic film in winter, and the trees are covered with plastic film.