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Pear tree iron deficiency susceptible to yellow leaf disease
Yellow leaf disease is mostly caused by poor ventilation of the orchard soil, intense erosion, too solid or too loose soil texture, too much or too little rain, so that the iron element is in a fixed state and is not easily absorbed by the pear tree. Wu Yanyan said that yellow leaf disease in pear trees mainly manifests on the leaves, especially on the tip of new shoots. The leaf color at the beginning of the disease is green and yellow, and the veins remain green, causing the leaves to show a green reticular pattern. During the vigorous growing season, the symptoms are obvious. In addition to the main veins and midribs, the top neophyte leaves become yellow-white or yellow-green. In severe cases, all the leaves from the tip to the branches become yellow and green, and the tip of the shoot is dead. So that the fruit can not develop normally, become hard and small, early fall off, leading to premature aging of the tree.
Yellow leaf disease in alkaline soil
In the case of yellow pear disease, the pH value of the soil is often greater than 8, which makes it easier to form soil compaction. Secondly, since this kind of soil is alkaline soil, the Fe2+ in the soil is converted to Fe3+, which reduces the ability of the soil to be treed. The concentration of Fe2+ absorbed by the body, at the same time, due to the higher concentration of Ca2+ in the soil, the antagonistic effect between the ions is inhibited, and the normal absorption of Fe2+ by the pear tree is inhibited, resulting in the lack of iron-containing catalysis in the process of chlorophyll biosynthesis. Enzymes do not synthesize chlorophyll and form yellow leaves.
Yellow leaf disease prevention and treatment
The physical method requires deep plowing of the mature soil. After the fruit is harvested, it should be combined with autumn basal fertilization, water storage and deep ploughing in combination with the tree conditions, so that the soil will be changed year by year, and the partial soil of the base of the tree body can be removed from the established pear orchard. Fill in the humus soil, improve the local soil environment of the roots, and ensure that normal pear orchards will be deep-turned 15-20 centimeters each year. At the same time, it is appropriate to make dwarf crops and cover rice straw in the pear orchard, which can inhibit the growth of weeds, preserve water and fertilizer, and increase the content of soil organic matter and mineral nutrients.
The chemical method guarantees the supply of trace elements on the basis of autumn basal fertilization. Wu Yanyan said that ferrous sulfate can be applied to the roots. Plants that are 5 to 10 years old can add ferrous sulfate per plant in the applied basal fertilizer. 250 g quantities; and ferric sulphate is sprayed on the leaves of growing plants, followed by topdressing of long leaf fertilizers before sprouting, and pears from 3 to 5 years old are treated with 15-45 g per plant. The amount is carried out. At the same time, the condition of the pear orchard was measured once every several years to determine the soil fertility, and the fertilizer type was adjusted according to the soil fertility status to determine the amount of fertilizer. Appropriately reduce nitrogen fertilizer application and increase phosphorus and potassium fertilizers. In addition, a 0.2% to 0.5% ferrous sulfate solution may be injected into the trunk using a high-pressure syringe, or a hole may be drilled in the trunk. Each of the strains is stuffed with 1-2 g of ferrous sulfate into the hole, and a paraffin or a wooden wedge is used in time. The tree holes are plugged to replenish the Fe2+ required for tree growth.
Two-pronged Approach to Pear Disease Yellow Leaf Disease
Pear yellow leaf disease, also known as yellowing disease, white leaf disease. In recent years, pear yellow leaf disease has performed very clearly. If you do not pay close attention to prevention and control, the tree will gradually weaken and eventually die. Therefore, it is particularly important to do a good job of preventing and curing pear yellow disease. Wu Yanyan, a senior agronomist in soil nutrition, said that improving the soil and improving soil fertility is the fundamental measure for the prevention and treatment of pear yellow disease.