First, the symptoms of calcium deficiency in vegetables
Calcium deficiency is mainly caused by physiological disorders of metabolism in crops. Generally, acid soils are prone to calcium deficiency. In the absence of calcium, the apical bud, lateral bud, root tip and other meristematic tissues of the plant first appeared deficiency syndrome, plant growth was blocked, the internodes were short, the plants were short and soft, and the young leaves were curly and deformed, fragile, mostly nicked, leaves The edge is yellow, gradually dying, and the tip of the leaf is sticky, not strong or rarely strong. Such as cabbage, Chinese cabbage and lettuce, calcium deficiency will occur in leaf coke, tomato, pepper, watermelon and other calcium deficiency will appear umbilical rot. The symptoms of calcium deficiency in several vegetables are as follows:
1. Calcium deficiency in Chinese cabbage: the leaf edge is rotted, the inner leaf edge is water-immersed, to brown necrosis, and when dry, it looks like bean curd skin, also known as dry heartburn, dry edge, and internal top fever.
2. Calcium deficiency in tomato: The top of young leaves is yellow, the plants are thin, wilting, petiole curls, top buds die, necrotic tissue around the top buds, roots are underdeveloped, roots are short, branches are many, brown. Fruit is prone to heart rot or hollow fruit.
3. Calcium deficiency in cucumber: white transparent rot spots between leaf margin and veins, chlorosis between severe clocks, dwarfing of plants, tenderness of young leaves, yellowish white flowers, small and tasteless melons.
4. Calcium deficiency in lettuce: growth is inhibited, young leaves are curled and deformed, and the leaf margin is brown to gray. In severe cases, the young leaves die from the top to the inside, and the dead tissue is grayish green.
5. Calcium deficiency in cabbage: The leaves are curled, tarnished, with white streaks, and the growth point is dead.
6. Calcium deficiency in carrots: leaves are chlorotic, necrotic, eventually dead, and the leaves are sparse.
7. Calcium deficiency in celery: young leaves die early, grow thin, leaves are grayish green, growth points die, leaf tips at the tip of the leaflets are distorted and blackened.
Second, the symptoms of excessive calcium in vegetables
Excessive application of calcium fertilizer in field conditions can cause abnormal growth and metabolism of vegetable plants, and has no significant effect on the yield and quality of vegetables, but it is easy to cause the content of trace elements such as zinc, iron and manganese to decrease.
3. Types of calcium fertilizer suitable for vegetables and application methods
1. Limestone: 95% to 98% calcium carbonate. After the limestone is ground, it passes through a 1.5mm sieve to form a limestone powder. Large amounts of application do not cause excessive soil alkalinity.
2. Gypsum: containing more than 80% of calcium sulfate. Agricultural gypsum is a white or gray powder obtained by pulverizing gypsum ore and passing through a 0.25 mm aperture. In addition to providing calcium nutrition to crops, sulfur is also available.
3. Calcium nitrate: 19% water-soluble calcium, 15.5% nitrogen, very hygroscopic, and sealed during storage. The aqueous solution is acidic.
4. Lime: Includes quicklime and slaked lime, which are commonly used in the production of calcium fertilizer.
Quicklime, limestone is calcined to form quicklime, also known as calcined lime, containing 90% to 96% of calcium oxide, strong alkaline, highly hygroscopic, white powder or blocky, and has a strong ability to neutralize soil acidity. Excessive application of quicklime will lead to a decrease in the effectiveness of nutrients such as iron, manganese, zinc, copper and boron in the cultivated soil, and even induce nutrient deficiencies, which is not conducive to the growth of vegetables.
After slaked lime and quicklime absorb water, it transforms mature lime. When it absorbs water, it releases a lot of heat. It is also called slaked lime. It contains about 70% calcium oxide. It is strongly alkaline and has the ability to neutralize soil acidity weaker than quicklime.
The application of lime helps to reduce disease, increase yield, improve quality, increase soil pH and improve soil structure. In acidic soils, lime can eliminate the toxicity of aluminum, increase the adsorption of calcium on the surface of soil colloids, improve the stability, aeration and water permeability of soil structure, improve the growth and development of crops, and promote soil. Beneficial microbial activity accelerates the decomposition of organic matter and nutrient release, increasing the effectiveness of phosphorus in the soil. Lime is a strong alkaline substance that kills germs and eggs in the soil and also eliminates weeds. The amount of lime applied is related to soil type, pH, crop type and purpose of application. Generally, 40 to 80 kg of quicklime or slaked lime is suitable for every 667 square meters of soil. The application of lime in soils with strong acidity such as red soil in dry land is better, and should be applied more, and slightly acidic or neutral soils may be applied less or not. For sandy soils, the amount of lime should be appropriately reduced, generally 50 to 75 kg per 667 square meters.
Can be used as base fertilizer and top dressing, but not suitable for seed fertilizer. As a base fertilizer, lime and farmyard manure are applied together during soil preparation, and it can also be combined with green manure. 50-70kg per 667 square meters of vegetable plots. If used for soil improvement, 150-250kg should be applied for every 667 square meters. When planting soy-sweet vegetables such as soybeans and roots on calcium-deficient soil, use 15 to 25 kg of lime per 667 square meters, ditch or hole application. Cruciferous vegetables such as radish and Chinese cabbage are mixed with lime and organic fertilizer when transplanting seedlings, which can effectively prevent clubroot disease. For topdressing, no lime is used as the base fertilizer during the preparation of the soil. It can be applied with lime, strips or holes during the growing period of vegetables, and 15kg per 667 square meters. Note that lime should not be used excessively because lime is strongly alkaline and should be applied evenly. Avoid contact with seeds or roots when applying ditch and acupoints. The application of lime must be combined with the application of organic fertilizers and nitrogen, phosphorus and potassium fertilizers, but the lime and human animal excrement and ammonium nitrogen fertilizers should not be stored or applied in combination, and should not be stored and applied in combination with superphosphate. The lime has a residual effect of 2 to 3 a. When the amount of application is large, the application amount in the second year and the third year can be gradually reduced, and then the application is stopped for 2 years and then re-applied.
Calcium deficiency is mainly caused by physiological disorders of metabolism in crops. Generally, acid soils are prone to calcium deficiency. In the absence of calcium, the apical bud, lateral bud, root tip and other meristematic tissues of the plant first appeared deficiency syndrome, plant growth was blocked, the internodes were short, the plants were short and soft, and the young leaves were curly and deformed, fragile, mostly nicked, leaves The edge is yellow, gradually dying, and the tip of the leaf is sticky, not strong or rarely strong. Such as cabbage, Chinese cabbage and lettuce, calcium deficiency will occur in leaf coke, tomato, pepper, watermelon and other calcium deficiency will appear umbilical rot. The symptoms of calcium deficiency in several vegetables are as follows:
1. Calcium deficiency in Chinese cabbage: the leaf edge is rotted, the inner leaf edge is water-immersed, to brown necrosis, and when dry, it looks like bean curd skin, also known as dry heartburn, dry edge, and internal top fever.
2. Calcium deficiency in tomato: The top of young leaves is yellow, the plants are thin, wilting, petiole curls, top buds die, necrotic tissue around the top buds, roots are underdeveloped, roots are short, branches are many, brown. Fruit is prone to heart rot or hollow fruit.
3. Calcium deficiency in cucumber: white transparent rot spots between leaf margin and veins, chlorosis between severe clocks, dwarfing of plants, tenderness of young leaves, yellowish white flowers, small and tasteless melons.
4. Calcium deficiency in lettuce: growth is inhibited, young leaves are curled and deformed, and the leaf margin is brown to gray. In severe cases, the young leaves die from the top to the inside, and the dead tissue is grayish green.
5. Calcium deficiency in cabbage: The leaves are curled, tarnished, with white streaks, and the growth point is dead.
6. Calcium deficiency in carrots: leaves are chlorotic, necrotic, eventually dead, and the leaves are sparse.
7. Calcium deficiency in celery: young leaves die early, grow thin, leaves are grayish green, growth points die, leaf tips at the tip of the leaflets are distorted and blackened.
Second, the symptoms of excessive calcium in vegetables
Excessive application of calcium fertilizer in field conditions can cause abnormal growth and metabolism of vegetable plants, and has no significant effect on the yield and quality of vegetables, but it is easy to cause the content of trace elements such as zinc, iron and manganese to decrease.
3. Types of calcium fertilizer suitable for vegetables and application methods
1. Limestone: 95% to 98% calcium carbonate. After the limestone is ground, it passes through a 1.5mm sieve to form a limestone powder. Large amounts of application do not cause excessive soil alkalinity.
2. Gypsum: containing more than 80% of calcium sulfate. Agricultural gypsum is a white or gray powder obtained by pulverizing gypsum ore and passing through a 0.25 mm aperture. In addition to providing calcium nutrition to crops, sulfur is also available.
3. Calcium nitrate: 19% water-soluble calcium, 15.5% nitrogen, very hygroscopic, and sealed during storage. The aqueous solution is acidic.
4. Lime: Includes quicklime and slaked lime, which are commonly used in the production of calcium fertilizer.
Quicklime, limestone is calcined to form quicklime, also known as calcined lime, containing 90% to 96% of calcium oxide, strong alkaline, highly hygroscopic, white powder or blocky, and has a strong ability to neutralize soil acidity. Excessive application of quicklime will lead to a decrease in the effectiveness of nutrients such as iron, manganese, zinc, copper and boron in the cultivated soil, and even induce nutrient deficiencies, which is not conducive to the growth of vegetables.
After slaked lime and quicklime absorb water, it transforms mature lime. When it absorbs water, it releases a lot of heat. It is also called slaked lime. It contains about 70% calcium oxide. It is strongly alkaline and has the ability to neutralize soil acidity weaker than quicklime.
The application of lime helps to reduce disease, increase yield, improve quality, increase soil pH and improve soil structure. In acidic soils, lime can eliminate the toxicity of aluminum, increase the adsorption of calcium on the surface of soil colloids, improve the stability, aeration and water permeability of soil structure, improve the growth and development of crops, and promote soil. Beneficial microbial activity accelerates the decomposition of organic matter and nutrient release, increasing the effectiveness of phosphorus in the soil. Lime is a strong alkaline substance that kills germs and eggs in the soil and also eliminates weeds. The amount of lime applied is related to soil type, pH, crop type and purpose of application. Generally, 40 to 80 kg of quicklime or slaked lime is suitable for every 667 square meters of soil. The application of lime in soils with strong acidity such as red soil in dry land is better, and should be applied more, and slightly acidic or neutral soils may be applied less or not. For sandy soils, the amount of lime should be appropriately reduced, generally 50 to 75 kg per 667 square meters.
Can be used as base fertilizer and top dressing, but not suitable for seed fertilizer. As a base fertilizer, lime and farmyard manure are applied together during soil preparation, and it can also be combined with green manure. 50-70kg per 667 square meters of vegetable plots. If used for soil improvement, 150-250kg should be applied for every 667 square meters. When planting soy-sweet vegetables such as soybeans and roots on calcium-deficient soil, use 15 to 25 kg of lime per 667 square meters, ditch or hole application. Cruciferous vegetables such as radish and Chinese cabbage are mixed with lime and organic fertilizer when transplanting seedlings, which can effectively prevent clubroot disease. For topdressing, no lime is used as the base fertilizer during the preparation of the soil. It can be applied with lime, strips or holes during the growing period of vegetables, and 15kg per 667 square meters. Note that lime should not be used excessively because lime is strongly alkaline and should be applied evenly. Avoid contact with seeds or roots when applying ditch and acupoints. The application of lime must be combined with the application of organic fertilizers and nitrogen, phosphorus and potassium fertilizers, but the lime and human animal excrement and ammonium nitrogen fertilizers should not be stored or applied in combination, and should not be stored and applied in combination with superphosphate. The lime has a residual effect of 2 to 3 a. When the amount of application is large, the application amount in the second year and the third year can be gradually reduced, and then the application is stopped for 2 years and then re-applied.
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