How to plant walnut seeds
First of all, the picked walnuts need to be selected, and the seeds are generally trees planted for 20 to 30 years. Pick in autumn and mature season, then peel and dry, not too dry, and keep a certain amount of water. And then stored as seedling seeds.
The next step is the preliminary treatment of seeds. Walnut seeds are mixed in layers with sand and buried near the nursery, and then the buried land is covered with plastic sheets to make a closed shed to ensure proper moisture and temperature.
The buried seeds should be checked in time, and when the seeds crack or germinate more than half, they can be taken out for sowing. Be careful with the seeds, don't hurt the germ.
Mid-March to mid-April is the best time to sow. Before sowing, the nursery should be watered enough to make a good seedbed. Seedbeds are usually spaced 40 rows apart? 50cm ditching, plant spacing according to 15? 20cm sowing, when sowing, two suture lines are parallel to the ground, the depth is 3-5cm from the ground, and the soil is covered and compacted.
In the later stage of sowing, water and fertilizer management should be done well, and 100 kg can be sown per mu, and the yield of seven or eight thousand seedlings can be obtained, with considerable benefits.
Walnut planting conditions
Walnut has strong adaptability. Walnuts are widely distributed in China, with 2 1 province (city) planting walnuts. From 2 1008 north latitude? 32? From Mengla County, Yunnan Province to 44054 north latitude? Lexian County, Xinjiang; East longitude 750 15? Xinjiang Tashkurgan to East longitude 12402 1? Dandong, Liaoning. From Buweike village in Turpan, Xinjiang, about 30 meters above sea level, to Lasi in Tibet, 4200 meters above sea level. In Yunnan, from 2 1008 north latitude? 32? -290 15? 08? , east longitude 9703 1? 39 ? 1060 1 1? 47? At an altitude of 700? It was planted at 3200 meters. In such a vast area, the ecological conditions are very different and the soil types are diverse. Walnut, on the other hand, has strict requirements on suitable conditions, such as large differences, although it can survive, but it has poor growth and fruiting, poor economic benefits and little cultivation significance.
I. Elevation
From the vertical distribution of walnut in Yunnan, the lower the latitude, the smaller the vertical distribution range; The higher the latitude, the larger the vertical distribution range. The latitude of Xishuangbanna in Yunnan is lower than that of the whole province, and walnuts are generally distributed at an altitude of 800? Between 65438 and 0800 meters. The northern latitude of western Yunnan is high, and the distribution range of walnuts is also large, from 1000? 3200 meters. According to the survey of Lancang River basin, walnuts are distributed at an altitude of 900? 3200m, of which, the altitude 1800? Walnut grows well in the range of 2200m, with normal development, less pests and diseases, high yield and good quality. Below 1400 meters above sea level, the growth is poor, and pests and diseases, especially scarabs and moths, are more harmful; Above 2500 meters above sea level, the growth is abnormal, the economy is affected by freezing damage, the tree is weak, the fruit is few and the quality is poor.
What is the suitable altitude for planting Carya illinoensis in Yunnan? 1700m.
Second, the terrain.
Walnut is a positive tree species that likes light and is suitable for growing in the sunny place of the north wind.
The growth of walnut is generally better in the middle and lower part of hillside than in the upper part; Those growing on sunny and semi-sunny slopes are better than those growing on shady slopes; Gentle slope is better than steep slope; Qingbian and gully areas are better than ridges. According to the research station of Yunnan Academy of Forestry, two walnut trees with roughly the same growth condition, one on the sunny slope and the other on the shady slope, have twice the yield difference.
Three. edaphic condition
Walnut has strong adaptability to soil. As long as the soil layer is thick and well drained, fertile and barren soil can grow in hills, mountains and plains. In the valley with loose soil and good drainage, alluvial land is better. Groundwater level 1.5m below, pH 5.5? 8.2 Slightly acidic to slightly alkaline soil grows well in relatively neutral soil. When growing in fertile soil, because of the developed root system, it absorbs more nutrients, makes the tree strong, bears more fruits and has high yield; Poor soil has poor yield, few fruits, small fruits and low yield. In Yunnan, walnuts can be planted in all soils except the sandy soil is too loose, too sticky and the stones are too big. Generally, the soil types of walnuts are red soil, brown soil and purple soil. Especially sandy loam with deep soil layer, moist soil, high organic matter content, fertile soil, good physical and chemical properties and good water retention and drainage is the most ideal. Walnuts in Yunnan mostly grow in neutral to slightly acidic soil, with a pH value of 5.5? Between 7.5.
Walnut trees like fertilizer. Only when all kinds of nutrition are satisfied can we grow and develop normally, otherwise it will form? Little old tree? , or years of dead branches, can not form a yield. Fertilize according to the fertilizer requirement of walnut. Generally speaking, increasing soil organic matter content can promote the growth, development and fruiting of walnuts. Walnut trees like calcium and grow well in calcareous soil.
Four. Climatic condition
1, temperature
The natural producing areas of walnuts are mostly in warmer regions. Frost-free period 180 days or more, with an annual average temperature of 80C? The area of 160C can be planted. Walnut can tolerate the low temperature of -200C during dormancy, and some varieties can tolerate the low temperature of-300 C. After germination in spring, the cold tolerance is low, such as when the temperature drops to -20C? -40C can freeze the new shoots, and the temperature will drop to-10C during flowering and young fruit? At -20C, the output will be reduced due to freezing. When the temperature exceeds 380C in summer, the fruit is easy to be burned, and the nucleolus cannot develop normally or turn black.
The annual average temperature of walnut distribution area in Yunnan is 6. 1? 160C is more suitable. When the average temperature was lower than 120℃, the shell of walnut became thinner and even the kernel was exposed. When the temperature drops to about-100C in winter, the young branches of local walnuts will be frozen, especially the grafted seedlings of pickled walnuts introduced. In 2002, Linzhou suffered from drought and high temperature, sometimes the temperature was as high as 400℃ or above. Walnuts suffered severely and nuts shriveled.
2. Lighting equipment
Walnut is a positive tree species and likes light. Walnut needs sufficient light, and under the condition of poor ventilation, the yield of walnut trees is low. The reason for the low yield of laissez-faire trees is that the branches are closed and the light in the crown is insufficient. In the walnut orchard cultivated in pieces, marginal plants or single plants and single plants all show good growth and more fruits. On the same plant, the outer branches also bear more fruits than the inner cavity. The annual sunshine should be more than 2000 hours to ensure the normal growth and development of walnuts. Less than 1000 hours, the core-shell and nucleolus are underdeveloped. During the growing and fruiting periods, sunshine hours and intensity have an important relationship with walnut growth, flower bud differentiation, flowering and fruiting. Therefore, the selection of terrain, suitable planting density and tree opening, and the configuration of side branches should all consider the light problem.
During the growth and development of walnut fruit, if it is irradiated by strong light, it will cause fruit burns. For example, in July of Yangbi 1997, the solar radiation was too strong, which caused the walnut fruit in Yangbi Valley to be burned, and the upper part of the green fruit turned black and rotten after being injured, which reduced the yield due to the lack of kernel.
Step 3: Moisture
The growth and development of walnut need a lot of water, especially in the fruit development period. When the water is insufficient at seedling stage, the growth almost stops. Under the condition of excessive drought, the growth potential of trees is weak, the leaves are small, the fruits are small, and even a large number of flowers and fruits fall or the leaves wither, thus reducing the production and accumulation of nutrients. This situation is called. Physiological drought? , must be watered in time to correct. Under the condition of poor drainage and long-term water accumulation in the soil, especially when it is polluted, walnuts will lack oxygen, cause root rot and even suffocate the whole root system. Frequent rain in autumn often causes the exocarp to crack early, and the seed slope in the core-shell becomes brown and moldy. Affect the quality of walnuts.
The precipitation in the main producing areas of Yunnan is generally 800? 1000mm, if evenly distributed, can generally meet the needs of walnut growth and development, but in the spring drought, young trees need proper irrigation. 1990 A continuous drought occurred in the southern mountainous area of Yangbi County, and the rainfall from spring to autumn was more than 50% less than normal, which led to the abnormal results of walnuts in that year, not only less fruits, but also more than half smaller than normal, the nuts were not full, and the yield decreased greatly.
Three methods of pruning walnut after harvest
The first is to drain the periphery, that is, to drain the dense branches, overlapping branches, thinning branches and pests and diseases on the periphery of the crown. Cross branches can solve the illumination in the hole by retaining or withdrawing the culture branch group.
Second, strengthening the inner chamber means weakening the inner chamber branchlets, leaving old branches and new branches. Choose and leave some strong branches or long branches, and take? Put it first and then shrink it? Medium branching type, long cultivation period; Pay attention to the regeneration and rejuvenation of branches.
Third, the treatment of drooping, that is, timely treatment of the pouring branches (that is, drooping branches) under the back, thinning or cutting off the thick branches, or retracting the branches with upward branches to cultivate large branches under the back.