In recent years, the enthusiasm for planting walnut trees has greatly increased. However, from the perspective of planting conditions, the survival rate is generally low, the average survival rate is less than 65%, and the survival rate of some newly planted walnut gardens is less than 35%, resulting in uneven tree age and uneven tree vigor. Affected the improvement of the output per unit area. In view of this situation, we analyzed the reasons that affect the survival rate of walnut trees.
First, the reasons for the low survival rate of walnut trees
1. The quality of seedlings is poor. From the investigation, the survival rate of seedlings and weak seedlings with low degree of lignification is 30%-65%, and the survival rate of seedlings and seedlings with high degree of lignification is 80%-95%; from the death of seedlings, it is 70%. Dead seedlings were caused by poor seedling quality, including seedling disease, small roots, large wound surface, low lignification of seedlings, and draining from top to bottom. Specifically, the reasons for the poor quality of seedlings are as follows:
1 stocks of rootstock walnuts are complex. In order to reduce the cost of raising seedlings, some nursery farmers bought walnut seedlings from outside and then grafted them. Because foreign walnut species are not adapted to local environmental conditions, the affinity for grafting is poor, and low-temperature freezing damage often occurs, causing seedling death.
2 peach, apricot seedlings nursery. Some nursery households cultivate walnut seedlings directly after cultivating peaches and apricot seedlings. Since peaches and apricot seedlings are prone to rooting cancer, this will increase the risk of disease of walnut seedlings and affect the survival rate of planting. According to the survey, the incidence of root cancer is only 0.1% for walnut seedlings cultivated in habitats, while walnut seedlings are cultivated in peach and apricot seedlings. The incidence of root cancer is 3.5%.
3 raise the seedlings. In recent years, the price of good seedling walnut seedlings is good, but the farmer's land area is too small to be able to turn around. Most nursery farmers can only take care of the seedlings, which increases the number of similar soil pathogens and reduces similar nutrient elements, resulting in poor root development, weak growth, and seedling dryness. Not fulfilled.
4 Nursery fertilization is irrational. In order to produce strong seedlings, sufficient organic fertilizer should be applied before seedling raising, and 3,000 kg of fully-fertilized organic fertilizer should be applied per acre. Grafting seedlings must be applied for 2 chemical fertilizers for the first 7 months from July to August. 10 kg of urea or diammonium phosphate, followed by 15 kg of compound fertilizer containing phosphorus and potassium for the second time, watered after application. Some nursery families are pursuing the height of seedlings and promoting the growth of seedlings. In the later stage of growth, topdressing nitrogen fertilizers are still applied, causing the above-ground parts of the seedlings to stop growing at a proper time. The seedlings are not full, the shoots are not full, and the drying is serious after winter and some seedlings are pumped. The dry rate reached 35.4%.
5 under the tree nursery. Some peasant households use land to save land and increase land use efficiency. Due to the lack of light under the trees, the synthesis of organic matter is less, causing the seedlings to grow in length, not robust, and easy to drain in the winter.
6 Seedling branches have serious diseases. Many nursery households only pay attention to the prevention and control of insect pests, but ignore the prevention and treatment of diseases, resulting in some infected seedlings such as dry rot disease, died after the onset of colonization.
7 The seedling density is too large. The leaves of walnut are compound leaves and the leaves are large. The seedling density can not be too large according to the requirements. Generally, the number of seedlings per mu is about 6,000. Some nursery farmers are pursuing the number of 10,000 seedlings per mu, resulting in dense seedlings, poor light, and thin and dry seedlings.
8 shoots are severely rooted. Because the walnut tree is a deep root system, some nursery families do not have sufficient depth to raise seedlings, resulting in incomplete root systems. The roots of the seedlings are highly invasive and affect planting survival.
2. Improper planting, extensive management. Some people in the production have insufficient grasp of the growth habits of walnut trees, improper planting, and extensive management, resulting in low survival rate.
1 Ignore chemical treatment seedlings when planting. Due to the replanting of peach and apricot seedlings, the roots of the seedlings are severely affected, especially the root cancer disease. Even if the seedling stage does not show symptoms, the seedlings also carry a large number of pathogens. When planted in a more viscous soil plot, it is easy to induce Ill, died of seedlings.
2 planted too deep. Walnut trees like to grow in loose soil, plant too deep, affect the roots breathing, often causing the walnut trees to grow weakly and even die.
3 Improper management after planting. After planting seedlings, soil moisture requirements are more stringent at the seedling stage. After planting, water should be irrigated and covered with film to increase the ground temperature and promote root growth; seedlings should be covered with plastic bags to promote bud germination and prevent dryness; When in time, add water. However, in the production, due to water-free pouring conditions, individual people do not water or water when planting, causing drought in the early stage of seedling growth, and some watering too much, too much ground after planting, resulting in the ground temperature is too low, affecting root growth; The masses do not cover the film and do not wrap the bags; some of them did not timely conduct pest control during the growth of the seedlings after planting, and buds and young shoots were harmed by pests, all of which affected the survival rate.
3. The inter-office work is irrational. Some people planted seedlings in the wheat fields, leaving no tree trays, and intercropping with corn and other high-stem crops. In this way, the early stage competed with the wheat for water, the medium-term maize affected the light, and the late leafhopper harmed the trunk, which affected the survival rate.
Second, improve the survival rate of walnut trees planting measures
1. Strictly raise nursery clearance to improve seedling quality. In order to improve the quality of seedlings, it is necessary to completely change the bad seedling raising habits: disabling foreign walnuts as seedlings for seedlings; the walnut garden where root cancers occur, and nursery land can no longer be used as breeding grounds; Scientific fertilization applies more organic fertilizer; during the growth of seedlings, pest control is strengthened to prevent the leaves from falling off, and 600-times carbendazim or thiophanate-methyl solution may be sprayed for 2-3 times; Keep the root system intact and reduce trauma. Strict seedling quarantine and diseased seedlings should be eliminated immediately.
2. Scientific planting. When planting, select high-quality seedlings that are free of pests and diseases, complete roots, adequate seedlings, and full shoots, and dip for 15 minutes with 500-fold solution of thiophanate-methyl or root-cancer-nourishing liquid, and then dry and plant them. The nursery or the old orchard is planted with agricultural antibiotic 120 to disinfect the soil. It is best to replace the new soil with the tree hole. Before planting the tree points to be solid, the depth of planting should be appropriate, and the original soil marks should be exposed on the ground after being compacted.
3. Careful management after planting. Immediately after the planting, it was irrigated with water, set at 70-80 cm, and the trees were covered with mulch, cut wax seals, and the seedlings were dried in 30-40 cm plastic bags. After germination, pay attention to air release, timely picking bags, spraying pesticides to prevent pests and diseases. Planting should be enough for tree trays, and wheat, corn and other high-stalk crops should not be used, and intercropped peanuts, soybeans, and other dwarf crops should be suitable.
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