Many vegetable farmers have asked why the leek is the cause? In the cultivation process of amaranth, the leek often shows the phenomenon that the tip of the leaf is dry and yellow, and many people call this phenomenon a dry leek. After the yellow leaves and dried tips appear in the leek, many vegetable farmers will fight drugs. In fact, it is better to prescribe the right medicine.
First, the reason why the leek is dry
1. Harmful gas hazards
It is easy to produce a large amount of ammonia gas by applying a large amount of ammonium hydrogencarbonate in the amaranth, or by applying ammonium bicarbonate, spreading urea, cottonseed cake, etc. on the kneading surface. The amaranth that is affected by ammonia first appears to be fading, wilting, and then turns yellow to yellowish white, and gradually spreads downward from the tip of the leaf. If the affected part is not infected by germs, it will not rot. Elastic, soft, and flat when wet; twisted when dry. The affected plants grow slowly and the leaves appear rusty.
2. High temperature, improper ventilation
The temperature at which the leek grows is 5-35 °C. If the temperature is above 30 °C for a long time, or if it is suddenly fine after a cloudy day, high temperature will cause leaf wilting. The outer tip of the victim plant begins to turn brown, and then the leaves gradually die.
3. Trace element imbalance
During the growth period, the lack of trace elements makes it easy for the leek to appear dry and yellow. When the calcium is deficient, the heart leaves are yellow, and some of the leaves are dead; when the magnesium is deficient, the outer leaves are yellowed and dead; when the boron is deficient, the heart leaves are yellowed and the growth is blocked; if the boron is excessive, it usually starts to die from the tip; manganese is excessive, tender The leaves are slightly yellowed and the outer leaves are yellowed and dead.
4. Improper use of the drug
When the drug is used at a high temperature, the water in the drug solution evaporates rapidly, and the concentration of the drug solution is rapidly increased, which is likely to cause phytotoxicity. Vegetable seedlings have poor drug resistance, and the concentration of the liquid used is too high, which can cause phytotoxicity and cause dryness.
5. Gray mold occurs
After infection with gray mold, water spots on the initial leaf surface appear, and then become white or light gray spots, which develop downward from the tip of the leaf. In severe cases, the lesions are connected, forming large spots, and the upper or the whole of the leaves are withered. Humidity is too high, the temperature difference between day and night is too large, and gray mold can occur.
6. Soil acidification
Amaranth grows and develops neutral soil. During the growth process, if a large amount of acid fertilizer such as thin manure, cake fertilizer or ammonium sulfate is applied to the soil for a long time, it is easy to cause acidification of the soil. The amaranth grown in the acid soil is sour, causing the growth of the leaves of the leek to be slow and the leaves are thin. Long and narrow, the seedlings and outer leaves are dry and yellow.
Second, the leek dry tip solution
1. Use resistant varieties
You can use 791, Hanzhong and other varieties of amaranth with strong resistance.
2. Lime
The dry tip caused by acidic soil can adjust the pH of the soil with quicklime, but it can not be used in the shed to avoid ammonia damage.
3. Rational use of manure and fertilizer.
It can be applied with ammonium nitrate and urea. Do not use too much at one time. Master the principle of "small amount of polydext". Ammonium nitrate should be applied with water, and urea can be applied on the soil surface. Ammonium bicarbonate, cake fertilizer and manure are strictly prohibited. The decomposed organic fertilizer can be used to supplement various trace elements, and water is poured in time after fertilization. Chicken manure should be fully decomposed to avoid ammonia damage.
4. Proper use of pesticides
Avoid excessive use of manganese-containing pesticides, such as mancozeb, to prevent the dryness of the leek caused by excess manganese.
5. Supplement trace elements.
It can spray the trace elements in “vibrant†for foliar application and supplement the trace elements.
6. Prevention and control of gray mold.
In the early stage of gray mold, timely use of ash (1+1) water-dispersible granules 600 times liquid spray control. Also note that spray should be applied after harvesting each leek.
The above is all about the prevention and treatment of the leek dry-tip phenomenon. You must pay more attention to the daily management of the leek in the weekdays. Although the leek is easy to grow, it is not necessary to manage.
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