The function of essential nutrient elements in garlic and its corresponding deficiency symptoms

Garlic likes loose soil rich in humus, has strong adaptability to soil acid and alkali, and grows well under slightly alkaline conditions. In different growth stages of garlic, nitrogen requirement was the highest, followed by potassium, calcium, phosphorus and magnesium. For every 1000 kg of fresh garlic, it is necessary to absorb 4.5 kg of nitrogen, 1.3 kg of phosphorus and 4.1 kg of potassium, and the proportion is about 0.25Mel 0.9.

The root system of garlic is string fleshy root system, which is mainly distributed in the plough layer of 5-25cm and belongs to shallow root vegetables. Garlic is sensitive to water and fertilizer, showing the characteristics of moisture, fertilizer and fertilizer tolerance. The root hair of garlic is few and thin, and the absorption capacity of the root is poor, so it is necessary to strengthen the fertilizer and water management during the growth period.

Nitrogen is one of the most important nutrient elements in garlic nutrient management. Because it is not only an important component of protein, but also a component of nucleic acid, nuclear protein, chlorophyll and many enzymes and hormones, it is the most important limiting factor of plant growth and development. The growth of shoot and root system were significantly inhibited under nitrogen deficiency. Nitrogen deficiency has the greatest effect on leaf development, the leaf is small and erect, the angle between the leaf and the stem is small, the leaf color is light green, and when it is serious, it is light yellow. The color of the green-lost leaves is uniform, and there are generally no spots or flower spots.

The normal supply of phosphorus is beneficial to cell division, proliferation, root extension and aboveground growth. Phosphorus can enhance photosynthesis and carbohydrate synthesis and transport.

Promote nitrogen metabolism and improve the adaptability of vegetables to the external environment. Phosphorus can improve the ability of drought resistance, cold resistance and disease resistance of vegetables. The leaves of phosphorus-deficient plants are small, dark green or gray-green in color, and lack of luster. The plant is slow, short, thin and erect, the root system is underdeveloped, the ripening is delayed, and the fruit is small.

Potassium can promote photosynthesis, and potassium can enhance plant resistance to stress, drought and lodging. When potassium deficiency occurs on the old leaves, the symptoms of potassium deficiency first appear on the old leaves, and then gradually expand to the new leaves. The old leaves and leaf edges first turn yellow, and then turn brown and scorch like burning. Garlic potassium deficiency 6-7 leaves began, the periphery of the old leaves produced white spots, the leaves bent to the back, and the white spots disappeared 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 is deficient in calcium, necrotic spots appear on the leaves. With the expansion of necrotic spots, the leaves bend down and the leaf tips die quickly. When there are symptoms of calcium deficiency, foliar fertilizer with more calcium and higher absorption and utilization should be sprayed in time.

Calcium deficiency usually occurs in fruits and old leaves, such as navel rot of tomato, dry heartburn of cabbage and so on.

Magnesium is the central element of chlorophyll molecules. Magnesium is the activator of many enzymes and participates in the metabolic process. Magnesium promotes the synthesis of vitamins. When garlic is deficient in magnesium, the leaves fade, first appear at the base of the old leaves, gradually develop to the tip of the leaves, and finally turn yellow and die.

In vegetable production, attention is often paid to the application of nitrogen fertilizer and potassium fertilizer, ignoring the supplement of magnesium fertilizer and antagonistic absorption of elements. the leaves of vegetables often show the symptoms of magnesium deficiency.

Sulfur is the structural element of protein. Sulfur is a key element in a series of volatile substances produced by crops. The plant shows light green and yellowish green. The young leaves are more obvious than the old ones. The plants are short and the leaves are small.

Boron is involved in the transport of photoassimilates. Boron is one of the key elements in plant reproductive growth. When the garlic is boron deficient, the new leaves are yellowed, the serious leaves die, the plant growth stagnates, and small brown cracks can be seen in the dissected leaf sheath. Boron-containing foliar fertilizer can be sprayed when this symptom occurs.

Iron: an essential element of chlorophyll; involved in electron transport.

Zinc: an essential element of chlorophyll; involved in the synthesis of auxin

Manganese: involved in photosynthesis; involved in the activities of the enzyme system.

Copper: component of chloroplasts; involved in the activity of the enzyme system.

Boron: involved in the transport of assimilates; is one of the key elements in plant reproductive growth.

Molybdenum: involved in nitrogen metabolism

Chlorine: participate in light and action; adjust osmotic pressure.

Lack of distinction between iron, manganese, copper and zinc:

Iron deficiency: yellowing albinism of new leaves, albinism of heart leaves, chlorosis between veins.

Manganese deficiency: young leaves lose green and yellowish, in severe cases, there are small black-brown spots, and may be necrotic and perforated.

Copper deficiency: the leaf tips are white and curly, there are many tillers, there are many lateral buds, and the roots stop growing.

Zinc deficiency: short plants, short internodes, lobular disease, interveinal chlorosis first appeared near the midrib of new leaves.

Farmers can make a diagnosis according to the specific performance of garlic and apply corresponding fertilizers to improve the yield and quality of garlic.