Calcium is an indispensable element in the growth and development of vegetable crops, and most vegetables are hi calcium. In the case of calcium deficiency, it will cause crop physiological disorders, plant growth is blocked, fruit and vegetables are not strong, or cause other physiological diseases. In recent years, not only is there a lack of calcium in open field vegetables, but also the lack of calcium in protected areas has become more serious.
Calcium deficiency symptoms
Since calcium is an inactive element, there is little movement of calcium in the phloem, and the downshift of calcium in the root system is limited. Generally, young calcium and calcium are very likely to be found on the young leaves and young tissues. The performance of the new parts of the plant such as the top bud, root hair growth, stagnant, atrophic death, new leaf adhesion, can not be normal expansion, the new leaves are often coke edge, incomplete; incomplete plant short and soft, short time to ask; fruit prone to depression, Dark brown necrosis; growth point necrosis when severe calcium deficiency occurs.
Causes of calcium deficiency
1. Soil factors The effective calcium content in the soil is low, which does not meet the calcium requirements of calcium-sensitive vegetable crops; the high soil salinity inhibits the absorption of water and calcium by the root system; the soil is acidic, affecting the availability of calcium, nor Conducive to vegetable absorption of calcium; Soil drought makes the concentration of soil solution increased, reducing the root water absorption, thereby inhibiting the absorption of calcium; Soil cultivation layer shallow, over sand, resulting in poor water retention and fertility, causing loss of calcium; soil too viscous, calcium The poor activity is not conducive to crop absorption.
2. Partial application of nitrogen fertilizer in the current vegetable production, fertilizer application is increasing, while the use of organic fertilizer is decreasing, especially in some high-yield areas, protection facilities, excessive application of nitrogen fertilizer, not only increase the effect of small, economic Wasted and pollute the environment. There is an antagonistic effect between nitrogen and calcium, excessive application of nitrogen fertilizer, thereby reducing the effectiveness of calcium in the soil, affecting the absorption of calcium in vegetable crops, causing the occurrence of calcium deficiency.
3. Water supply imbalance When the normal supply of water and plant normal growth, the water balance between the various organs of plants, the absorption of calcium can meet the needs of crop growth; when the soil is too dry or too wet, the effective calcium content decreases, affecting the absorption of vegetables. The mobility of calcium in the soil is reduced, and the diffusion rate in the soil is slowed down. The roots of vegetable crops are limited by the liquid mechanism to absorb calcium and are prone to calcium deficiency.
4. In case of excessive soil moisture, the root injury causes the roots of vegetable plants to be stunted, and the application of unripe organic fertilizers or excessively high fertilization rates causes burning of roots, which affects the normal absorption of water and calcium deficiency.
Prevention
1. Apply organic fertilizer, base fertilizer calcium.
Organic fertilizers are rich in nutrients, which can improve the physical structure and chemical properties of the soil, increase the ability of the soil to retain water and fertility, reduce drought damage, and promote the absorption of calcium and other nutrients by vegetables. At the same time, decomposed organic fertilizers can prevent damage to the root system. Generally combined with 2,000 to 3,000 kilograms per acre arable land maturity organic fertilizer, then add 30 to 50 kg of superphosphate, do fertilizer calcium.
2. Rational use of lime, soil reform soil.
Lime is a commonly used calcium fertilizer. Applying lime on acidic soils will help increase soil pH and improve soil structure, and it will also help reduce disease, increase yield, and improve quality.
The application amount of lime is related to soil type, pH, and crop type. Generally, 40-80 kg of quick lime or hydrated lime per acre is more suitable. The amount of lime in the soil should be appropriately reduced. When the soil is used for reform, 150-250 kg should be applied per mu.
3. Deep plowing, brazing, mulching cultivation.
Deep plowing, drying, fully ripening the soil, improving the physical and chemical properties of the soil, and enhancing the ability to retain water and fertility; using mulching film to maintain the relative stability of soil moisture and reduce the loss of calcium.
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