sos box,High Quality sos box,sos box Details, CN Dongguan City Risen Medical Products Co., Ltd. , https://www.risenppe.com
Causes and Measures of Yellow Leaves of Cucumber
First, the lower leaves yellow (fresh yellow) is a lack of nitrogen. Nitrogen compounds are highly mobile in plant vines. After the soil is deficient in nitrogen, nitrogen in the old leaves will migrate to the new tissue to maintain growth, resulting in yellowing of the leaves from bottom to top, showing a fresh yellow-orange color. The leaves of the yellow leaves are soft and withered, chlorosis inward from the leaf margins, and the roots are slender, with few in number; after the plants lose their growth vigor, the capillary roots turn brown. About 10 kg of nitrogen per acre is applied to nitrogen-deficient soil, which can effectively prevent functional yellowing. Second, the entire leaf yellow (light yellow rust) is a nitrogen surplus. If there is too much nitrogen, a large number of proteins and chlorophyll are formed, cell division is accelerated, the nutrition body is lengthy, and the leaf area is increased, resulting in mutual shade, poor ventilation and light transmission. Excessive addition of nitrate nitrogen will inhibit the absorption of iron and magnesium, resulting in yellowing of the entire upper and lower leaves, showing pale yellow rust. Excessive nitrogen also inhibits the absorption of boron, zinc, phosphorus, and potassium. If this symptom occurs, stop applying nitrogen fertilizer in the near future. The nitrogen fertilizer is applied less in the early stage of growth, and the amount per acre is controlled at 10-15 kilograms in the middle and later stages, so that the total pure nitrogen content per acre of land is controlled at about 20 kilograms, which can ensure continuous and stable production without causing too much nitrogen. Plant reverse osmosis and scarring. Third, the leaf edge yellow (yellow-white) is potassium deficiency. Potassium is the activator and transformant of many enzymes in the plant and it is the main component of stems and fruits. The leaf potassium is present near the leaf veins. The most sensitive site for potassium is the leaf margin between the leaf margins and the two main veins that are far from the main vein of the leaf. If potassium is missing, these two sites begin with yellow and the protruding mesophyll Yellowing is especially heavy, yellow-white. Excessive nitrogen, potassium to reduce potassium to reduce nitrogen, usually applied once per acre 8-25 kg of potassium sulfate, should not be excessive. Potassium still has the effect of increasing production in new vegetable fields and under sufficient conditions, but too much potassium can cause chlorosis between the middle and lower parts of the veins, and the leaf margins turn white and yellow. 4. Leaf yellowing (beige) is a surplus of phosphorus. If too much phosphorus is applied, the respiration of the plant will be abnormally operated, which will consume a lot of nutrients, which will lead to the rapid growth of the system organs and early development of premature aging. The number of melons is large and small, and the color of the leaves is initially dark green or gray-green, and the new leaves are small and thick. , from the edge of the leaf area inward faded green and yellow, was yellow. In the greenhouse cucumber field, about 15 kilograms of available phosphorus (about 100 kilograms of superphosphate and 40 kilograms of phosphorus nitrate) are applied at the base fertilizer point, and about 5 kilograms of available phosphorus per acre is applied at the middle and late stages of growth (ie, phosphorus nitrate 10). Kilograms or about 5 kilograms of diammonium phosphate) can meet the need for normal growth of phosphorus, prevent the excessive application of phosphorus causing ion-inhibiting interactions and failure, or causing the plant to poison the malignant environment without causing long-term vigor and yellowing the leaves. Fifth, the mesophyll yellow (deep beige) is magnesium deficiency. Magnesium is a component of chlorophyll, such as magnesium deficiency, chlorophyll can not be normal synthesis, there will be chlorotic leaf yellow, dark yellow, especially in the middle leaves, large leaves and the central chlorosis of leaves, yellow leaf edge sagging Umbrella shaped. In production, it is necessary to control the amount of potassium that is applied. In general, 200 kg of vegetables are used per kilogram of pure potassium. Potassium will affect the absorption of magnesium. The foliar mancozeb and carbendazim manganese zinc can prevent leaf chlorosis. This is because manganese and zinc can promote the absorption of magnesium. Can also apply 20 kg of calcium magnesium fertilizer per acre in the onset of the disease to relieve the deficiency of magnesium caused by mesophyll yellowing. Six, vein yellow (light golden yellow) is zinc deficiency. When the cucumber cultivars are deficient in zinc, the content of auxin is decreased and the growth is inhibited. The short leaves between the stems are hard, the new leaves are small, and the leaf margins are drooping. In severe cases, the melon toppings or clusters of leaf growth points appear, symptoms like virus disease, veins The chlorosis was pale golden yellow. Applying 1 kg of zinc sulfate per acre can relieve vein yellowing, aging leaves, turtle heads and melon topping. If mancozeb is often used to control downy mildew, cucumbers rarely suffer from zinc deficiency. Seven, edge yellow (linear yellow) is a lack of boron. Boron participates in the distribution and operation of carbohydrates. The leaves of the vacant leaves are hypertrophic and crusted. The veins are yellowing from the veins to the leaves. The blades are deformed outward and the leaf edges are whitishly whitishly thin. In severe cases, the growing leaves are shriveled and dried, and the cucumbers are lignified and empty. Overwintering cucumbers during the winter solstice to the Spring Festival, such as the temperature of less than 13 °C in the middle of the night, to the high temperature and the vigorous growth of May, the photosynthetic products can not be normal operation, the root of a small absorption capacity is weak, easy to cause boron deficiency syndrome. Ordinary foliar spray 1-2 times 800 times borax aqueous solution, or 1 kg of borax per acre topdressing can eliminate boron deficiency syndrome. Too much boron will inhibit the absorption of iron and the leaves will be yellow. Fresh yellow leaves (ginger yellow) are iron-deficient. Due to iron and chlorophyll synthesis, such as boron, phosphorus, calcium, nitrogen too much, or potassium deficiency, can easily lead to iron deficiency. The iron-deficient leaves are yellow, and they first appear at the top of the growth, that is, the new leaves at the growing point are bright yellow, and the fresh cucumber skin is yellow. The solution is to apply 5 kg of ferrous sulfate per acre to the iron-deficient soil. Potassium deficiency in the soil can also promote the absorption of iron.