What harm does grape iron deficiency disease have?

What harm does grape iron deficiency disease have? What causes iron deficiency in grapes? How to prevent and cure iron deficiency in grapes? Netizens with experience in grape cultivation are also asked to introduce grapes as perennial lianas, which are generally cultivated in greenhouses or equipment scaffolding, resulting in the vineyard soil being unable to plough for a long time, resulting in the deposition or loss of elements in the soil. resulting in symptoms of element deficiency. Today, the farming network has sorted out the harm, causes and prevention methods of grape iron deficiency, which are listed in detail below for netizens' reference. The harm of grape iron deficiency: grape iron deficiency when the new leaf vein chlorosis, gradually developed to the whole leaf is yellowish green to yellow, but the leaf vein still remains green; grape iron deficiency is serious from the diseased tip leaves, from top to bottom leaves are yellow-white to white, sometimes there are brown necrotic spots appear, the leaves seem to burn, and finally dry and die. The growth of new shoots is slow, and when the grapes are deficient in iron, the flower ear becomes light yellow, the fruit sets less, the fruit color is light and the grain is small, the development is poor and so on. The cause of iron deficiency in grape: iron can promote the activity of many enzymes in plants, and the synthesis of chlorophyll in plants is affected by iron deficiency. Iron in the field exists in the soil in the form of oxides and salts, and a small amount of iron is released after decomposition, which is generally absorbed by plant roots as divalent iron ions. In general, there is no lack of iron in the soil, but the absorption of iron by plants is hindered by soil conditions or other limiting factors. Such as poor drainage of clayey soil, low soil temperature, excessive salt content in saline-alkali soil or too old trees, aging trees and too much fruit, it is easy to cause difficulties in the absorption of iron and poor mobility of iron ions in plants. therefore, iron deficiency is common on new shoots or newly unfolded leaves. Grape iron deficiency mainly occurs in cold and humid weather in spring. Prevention and treatment of grape iron deficiency: method 1, cover the ground of the vineyard and loosen the soil in time to increase the ground temperature. And increase the application of organic fertilizer to adjust the soil PH value to between 6 and 6.5, so as to reduce the soil salt content. Method 2. Ferrous sulfate was applied to grapes before sprouting, and the application amount of ferrous sulfate per adult grape was 50g / 100g, which could be applied in ditch or hole, but the effect of mixed application with organic fertilizer was the best. Method 3. The vines can be sprayed with 0.1%-0.2% ferrous sulfate solution or 0.1%-0.2% ferrous sulfate solution + 0.15% citric acid solution by foliar spraying, with an interval of 15 to 20 days. Method 4. After pruning the grape, add 179-197g ferrous sulfate per liter of water to smear above the top bud of the grape. Prevention and treatment of magnesium deficiency in grape methods for prevention and treatment of boron deficiency in grape