Prevention and treatment of calcium deficiency in growing apple trees

Symptoms of calcium deficiency in apple trees: bitter pox disease formed in the early stage, spongy under the skin without decay. The red and black spots formed before harvest should be distinguished as infectious diseases or physiological diseases. The red and black spots formed by infectious diseases rapidly expand and go deep into the pulp and rot. Red spots and black spots formed by calcium deficiency are sunken and dry and shrink into black scars without decay, also known as bitter pimples. Gently cut off the epidermis with a knife, if the skin is spongy, it is a symptom of calcium deficiency during the fruit expansion period. If the subcutaneous pulp is normal, it is a symptom of calcium deficiency formed during fruit ripening. For calcium-deficient apples, due to the disappearance of cell-to-cell bonding, the cell wall and middle glue layer became soft and the cells ruptured. Not only the above symptoms of calcium deficiency appeared before harvest, but also bitter pox disease, water heart disease and softening of skin were also easy to occur during storage.

The causes of calcium deficiency are: first, there is a serious lack of calcium in the soil; second, it is caused by climatic factors that affect the transport of calcium.

1. Calcium ions move slowly in plants, and it is also a very slow process to supplement calcium from the soil. The transport of calcium in xylem depends on the transpiration of leaves. The transpiration of mature leaves is strong and calcium is abundant. The shoots with poor light in the terminal bud, weak bud and inner chamber and lower layer have less calcium because of weak transpiration. The transport of calcium in phloem is very weak, and calcium in mature leaves can not be reused by young leaves, root tips, branch growth points and fruits. Therefore, calcium deficiency in apple plants is first manifested in the new tissues of root tips, growth points, tender leaves and fruits, which is the internal cause of calcium deficiency in apples.

two。 Reviewing the historical experience and the reality of calcium deficiency symptoms in recent years, the external causes of calcium deficiency in fruit trees: ① fruit trees are in charge of chemical fertilizer for a long time, and the available medium and trace elements in the soil are on the verge of depletion, which has become a serious calcium deficiency state. ② applied a large amount of nitrogen, phosphorus and potassium fertilizer to inhibit the absorption of calcium. ③ serious drought, soil moisture decreased to less than 50% of the maximum soil water holding capacity, leaf wilting, that is, transpiration function weakened, affecting the transport of calcium. ④ waterlogging, calcium and other element deficiency will occur at the same time. During the period of rapid expansion of fruit before ⑤ harvest, there was no light in long-term overcast and rain, which affected the transport of calcium, resulting in serious symptoms of calcium deficiency, such as red spots, black spots, black scars and so on.

Prevention and treatment of calcium deficiency:

1. To get rid of the misunderstanding of chemical fertilizer, base fertilizer should be applied in autumn, mainly farm fertilizer and high-quality organic fertilizer, with 30,40kg silicon-calcium fertilizer per mu (such as calcium-magnesium phosphate fertilizer, calcium superphosphate, etc.). The content of available calcium in soil was increased by increasing soil organic matter and medium and trace elements to improve soil fertility. Due to the slow transport of calcium ions in the tree, the effect may not be obvious in that year. But sticking to it for several years is the inevitable way to fundamentally solve the problem of calcium deficiency.

two。 The soil supplements calcium. In the early stage of the first root growth peak in March, 20 kg of calcium nitrate was applied per mu.

3. Foliar calcium supplement. The use of amino acid calcium 300 times liquid or other chelated calcium liquid fertilizer. Spraying fruit for 5 or 6 times during sprouting, before flowering, flowering, young fruit stage and after bagging is a shortcut to supplement calcium, and good results can be obtained in the same year.

4. Through pruning, the inner chamber of the crown, the lower branches, to create a good lighting conditions.

5. Water in time in case of drought. In orchards without watering conditions, grass mulching or hole storage is carried out to keep the soil at 60% to 70% of the maximum water holding capacity.

6. Thicken the soil layer under the canopy, repair drainage ditches inside and outside the orchard, timely drainage into the rainy season, to prevent water under the tree into waterlogging.

7. During the fruit expansion period before apple harvest, when there is a long overcast and rainy day (plum rain), we should seize the day when there is no rain, spray the fruit 300 times of amino acid calcium, and spray the fruit as the main wet fruit bag.

8. Before entering the cellar (storage) after harvest, the apple was sprayed or washed with 300-to 400-fold calcium amino acid solution to prevent red spots, black spots, bitter pimples, textured skin, soft skin, water heart disease and other symptoms during storage.