Prevention and treatment of calcium deficiency in sunken necrotic vegetables with dwarf fruits

Calcium is an indispensable element for the growth of vegetables, and most vegetables like calcium. In the case of calcium deficiency, it will cause physiological disorders of vegetables, growth hindrance, fruits and vegetables do not bear fruit, or lead to other diseases. In recent years, calcium deficiency is more serious not only in open field vegetables, but also in protected vegetables.

Calcium deficiency in vegetables

Symptoms of calcium deficiency: calcium is an inactive element, there is little movement of calcium in phloem, limited downward movement of calcium in roots, and calcium deficiency is easy in young leaves, young tissues and fruits. It is characterized by stagnant growth of new parts of vegetables, such as terminal bud and root hair, atrophy and death, adhesion of new leaves, unable to expand normally, scorched edges of new leaves, mutilated; vegetables short and soft, short nodes; fruit tip easy to sunken, blackening and necrosis; severe calcium deficiency, growth point necrosis.

Reasons for calcium deficiency:

1. Soil factors: soil available calcium content is low, which can not meet the needs of calcium-sensitive vegetables; high soil salt content inhibits the absorption of water and calcium by vegetable roots; soil acidity is strong, which affects the availability of calcium and is not conducive to vegetable absorption; soil drought increases the concentration of soil solution and reduces root water absorption, thus inhibiting calcium absorption. The soil tillage layer is shallow and over-sand, resulting in poor water and fertility conservation and calcium loss; the soil is too sticky and the activity of calcium is poor, which is not conducive to crop absorption.

2. Partial application of nitrogen fertilizer: in vegetable production, the application amount of chemical fertilizer is increasing, while the use of organic fertilizer is decreasing, especially in some high producing areas and protection facilities, excessive application of nitrogen fertilizer not only has little effect on increasing production, but also wastes economically, and pollutes the environment at the same time. There is antagonism between nitrogen and calcium. Excessive application of nitrogen fertilizer reduces the availability of calcium in soil and affects the absorption of calcium by vegetables.

3. Imbalance of water supply: when the water supply is normal and the vegetables grow normally, the water supply among the organs of vegetables is balanced, and the absorption of calcium can meet the needs of vegetables; when the soil is too dry and wet, the content of available calcium decreases, affecting the absorption of vegetables. The mobility of calcium in soil decreased, the diffusion rate slowed down, and the absorption of calcium by vegetable roots was limited through the fluid mechanism.

4. Root injury: when there is too much water in the soil, the root system of vegetables is underdeveloped, and the root burning is caused by the application of unripe organic fertilizer or too high fertilizer concentration, which affects the absorption of water and leads to calcium deficiency.

Prevention and control measures:

1. Apply mature organic fertilizer and base fertilizer to supplement calcium.

Organic fertilizer is rich in nutrients in an all-round way, which can improve soil physical and chemical properties, improve soil water conservation and fertility, reduce drought damage and promote calcium absorption by vegetables. At the same time, mature organic fertilizer can avoid damage to the root system. Generally combined with cultivated land, 2000-3000 kg of mature organic fertilizer per mu, plus 30-50 kg of calcium superphosphate, to supplement calcium with base fertilizer.

2. Apply lime reasonably and improve the soil.

Lime is a commonly used calcium fertilizer. Applying lime to acid soil can not only increase soil pH value, improve soil structure, but also reduce diseases, increase yield and improve quality. The amount of lime application is related to soil type, acidity and alkalinity and crop species. Generally, it is more suitable to use 40,80kg quicklime or hydrated lime per mu. The amount of lime in sandy soil should be reduced appropriately, and 150-250 kg per mu should be applied when it is used to improve soil.

3. Deep ploughing, sun drying and plastic film mulching cultivation.

Deep ploughing, sun drying, fully mature soil, improve soil physical and chemical properties, enhance the ability of water and fertilizer conservation; vegetable cultivation with plastic film mulching to keep soil moisture relatively stable and reduce calcium loss.