Garlic root system is a string-like fleshy root system, which is mainly distributed in 5 ~ 25 cm plough layer and belongs to shallow root vegetables. Garlic is sensitive to water and fertilizer, showing the characteristics of moisture-loving, fertilizer-loving and fertilizer-tolerant. The root hairs of garlic are few and thin, and the root absorption capacity is poor. Therefore, the management of fertilizer and water should be strengthened during the growth period.
Nitrogen is one of the most important nutrient elements in garlic nutrient management. Because it is an important part of protein, it is also a component of nucleic acid, nucleoprotein, chlorophyll and many enzymes and hormones, and it is the most important limiting factor for the growth and development of garlic. Under the condition of nitrogen deficiency, the growth of garlic shoot and root system was significantly inhibited. Nitrogen deficiency has the greatest influence on the development of leaves, which are small and upright, with a small angle with the stem, and the color of leaves is light green, and in severe cases it is light yellow. The discolored leaves are uniform in color and generally do not appear spots or spots.
Potassium can promote photosynthesis, and potassium can enhance plant resistance, drought resistance and lodging resistance. When potassium deficiency occurs, the symptoms of potassium deficiency first appear on the old leaves, and then gradually spread to the new leaves. Old leaves and leaf margins turn yellow first, then brown, burning like burning. If garlic lacks potassium in 6 ~ 7 leaves, white spots will appear around the old leaves, and the leaves will bend backward, and the white spots will disappear with the death of the old leaves.
Calcium is an important component of cell wall. Calcium can promote the absorption of other nutrients. When garlic lacks calcium, necrotic spots will appear on the leaves. With the expansion of necrotic spots, the leaves bend downward and the tip of the blade dies rapidly. When calcium deficiency symptoms appear, foliar fertilizer with more calcium content and higher absorption and utilization rate should be sprayed in time. Calcium deficiency usually occurs in fruits and old leaves, such as navel rot of tomatoes and dry heartburn of cabbage.
The normal supply of phosphorus is beneficial to cell division and proliferation, and promotes root extension and aboveground growth and development. Phosphorus can strengthen photosynthesis and the synthesis and operation of carbohydrates.
Phosphorus can promote nitrogen metabolism and improve the adaptability of vegetables to the external environment. Phosphorus can improve the drought resistance, cold resistance and disease resistance of vegetables. Phosphorus-deficient plants have small leaves, dark green or grayish green, and lack luster. Plants grow slowly, are short, thin and erect, with underdeveloped roots, delayed maturity and small fruits.
Magnesium is the central element of chlorophyll molecule, and it is also the activator of many enzymes, participating in the metabolic process. Magnesium can promote the synthesis of vitamins. When garlic is deficient in magnesium, the leaves turn green, which first appears at the base of the old leaves, then gradually develops to the tip, and finally the leaves turn yellow and die. In vegetable production, the application of nitrogen fertilizer and potassium fertilizer is often emphasized, while the supplement of magnesium fertilizer is neglected, which has an antagonistic effect on the absorption of elements. The leaves of vegetables often show magnesium deficiency symptoms of greenness between veins.
Sulfur is the structural element of protein. Sulfur is the key element of a series of volatile substances produced by crops. These plants are light green and yellowish green. Young leaves are more obvious than old leaves. Plants are short and have small leaves.
Boron participates in the transport of light-shrinkage compounds. Boron is one of the key elements in plant reproductive growth. When garlic is short of boron, the new leaves turn yellow. In severe cases, the leaves die, the plant growth stagnates, and small brown cracks can be seen in the anatomical leaf sheath. When this symptom occurs, foliar fertilizer containing boron can be sprayed.
Iron is an essential element of chlorophyll and participates in electron transfer.
Zinc is an essential element of chlorophyll and participates in the synthesis of auxin.
Manganese participates in photosynthesis and enzyme system.
Copper is a component of chloroplast and participates in the activities of enzyme system.
Boron participates in the transport of assimilates and is one of the key elements in plant reproductive growth.
Molybdenum participates in nitrogen metabolism.
Chlorine participates in photosynthesis and regulates osmotic pressure.
Lack of distinction between iron, manganese, copper and zinc;
Iron deficiency: the new leaves are yellow and white, the heart leaves are often albino, and the veins are green and distinct.
Manganese deficiency: young leaves turn green and yellow, and in severe cases, dark brown spots appear, which can lead to necrosis and perforation.
Copper deficiency: the tip of the leaf is white and curly, with many tillers and lateral buds, and the root system stops growing.
Zinc deficiency: short plants, short internode clusters, lobular disease, and chlorosis between the first veins near the midvein of new leaves.
Farmers can diagnose garlic according to its specific performance and apply corresponding fertilizers to improve the yield and quality of garlic.