symptom
Manganese is not easy to move in the plant body, and it is less mobile. The function of manganese is to promote the activity of enzymes in the growth process and assist in the formation of chlorophyll. When manganese is deficient, the young leaves show symptoms first, the tissue between the veins becomes chlorotic and yellow, and small yellow spots appear, which are similar to mosaic symptoms and are limited by the smallest green veins.
The leaves on both sides of the first and second veins still remain green, and the leaves exposed to the sun are more obvious than those in the shade. Further manganese deficiency will affect the growth and maturity of new shoots, leaves, and fruit grains. In the soil containing lime, the symptoms of manganese deficiency are often covered by the yellowing of lime chlorosis, which should be paid attention to.
Manganese deficiency symptoms should be distinguished from zinc deficiency, iron deficiency, and magnesium deficiency. Zinc deficiency symptoms first occur on new growth and distort the leaves. Iron deficiency causes thinner green veins on new shoots, lined with yellow mesophyll tissue.
The symptoms of manganese deficiency and magnesium deficiency are similar. They first appear in the base leaves, mostly between the first and second veins, and develop into a yellow band. However, the boundary of the chlorotic part of manganese deficiency is not clear, and there is no browning and dying phenomenon.
Etiology
Manganese generally exists in the physiologically active parts of plants, especially in leaves, which can promote photosynthesis and carbohydrate metabolism of plants. Manganese deficiency will hinder the formation of chlorophyll, affect protein synthesis, and cause the symptoms of chlorosis and yellowing.
Generally, there is no manganese deficiency under acidic soil conditions, but manganese deficiency is more likely to occur in soil with heavy clay, poor ventilation, high groundwater level, and high pH value. The test results show that when the petiole contains 3-20mg/kg manganese, manganese deficiency will appear.
Prevention method
(1) Increasing the application of organic fertilizers to improve the physical and chemical properties of the soil can prevent manganese deficiency.
(2) For manganese-deficient vineyards, spraying 0.3% to 0.5% manganese sulfate solution before flowering can adjust the manganese deficiency, increase yield and promote fruit ripening.
Specific recipe: Dissolve 400g of manganese sulfate in 13L of water. Take another 200g of quicklime and dissolve it with hot water, add water to 13L, stir well, slowly add the quicklime aqueous solution into the manganese sulfate solution and stir, and finally add it to 130L, spray 667m2 of vineyards, usually spray twice before flowering, interval 7 days.
