Leting County is a big county producing thin-skinned melons with an area of ​​130,000 mu. Due to the long years of planting, the symptoms of deficiency of trace elements have begun to appear in production. In order to avoid the occurrence of such diseases and improve the quality and yield of thin-skinned melons, the diagnosis and control techniques for the physiological deficiency of thin-skinned melons are presented below. .
One, magnesium deficiency syndrome
1. Symptoms. In the process of growth and development, the mesophyll of the lower lobe gradually loses green and yellow, and is further developed. In addition to the green leaves of the leaves, the leaves are yellow. The symptoms of magnesium deficiency are similar to those of potassium deficiency. The difference is that magnesium deficiency is caused by the loss of green from the inside of the leaf, and the lack of potassium begins with the loss of green from the leaf margin. There are differences in the degree of symptoms and symptoms between the varieties.
2. Diagnosis points. The occurrence of chlorosis before the beginning of the childbearing period and the occurrence of cucurbits is unlikely to be caused by magnesium deficiency, and it may be due to gas barriers in the protected area. Note that the position of the leaf where the chlorosis occurs is probably due to chlorosis in the upper lobe. In the absence of magnesium, the leaves do not curl up. If they are hardened, curling should be considered for other reasons. The chlorosis is divided into leaf margin chlorosis and inward expansion and leaf margin chlorosis between green veins. The former is potassium deficiency and the latter is magnesium deficiency.
3. Countermeasures. Before the cultivation, the soil can be tested, for example, magnesium deficiency should be applied to enough magnesium fertilizer; pay attention to the content of potassium and calcium in the soil, and maintain the appropriate salt base level of the soil; avoid excessive application of potassium, nitrogen and other fertilizers that hinder the absorption of magnesium. The emergency response is to spray 1% magnesium sulfate solution on the foliage.
Second, zinc deficiency
1. Symptoms. Fading from the middle lobe, the veins are clearly visible compared to the healthy leaves. As the veins fade gradually between the veins, the leaf margins turn from yellow to brown. As the leaf margins die, the leaves curl slightly to the outside, and the internodes near the growth point are shortened, but the new leaves are not yellowed.
2. Diagnosis points. Zinc deficiency mostly occurs in the middle and lower lobes, while the upper lobe does not generally appear yellow. The middle leaves of plants are yellowing, bending outwards and hardening. Because of the lack of zinc, the hormone content can be reduced, inhibiting the internode elongation. Zinc deficiency is similar to potassium deficiency and yellow leaves. In the absence of potassium, the leaf margin is yellowed first and gradually develops inward. In the absence of zinc, the entire leaf yellows and gradually develops toward the leaf margin. The difference between the two is that the order of Huanghua is different. When the symptoms of zinc deficiency are severe, the internodes near the growth point are shortened. Plant leaf sclerosis may also be potassium deficiency, such as the severity of zinc sclerosis hardened.
3. Countermeasures. The soil should not be over-used with phosphate fertilizer; Under normal circumstances, zinc deficiency can be applied with 1.5 kg of zinc sulphite per acre when zinc deficiency occurs; the emergency solution is to use 0.1%-0.2% zinc sulfate aqueous solution for foliar spray.
Third, calcium deficiency
1. Symptoms. The upper lobe is slightly smaller and curls toward the inside and outside. After a long period of continuous low temperature, insufficient sunshine, and severe sunny days, the leaf margins near the growth point curled to death. The upper leaves are yellowed between veins, and the leaves become smaller, showing dwarfing symptoms.
2. Diagnosis points. Observe carefully the symptoms of leaf yellowing near the growing point. If the veins are not yellowing, they may be virus diseases. The same symptoms occur on the median lobe, while the upper lobe is healthy, but it may be lacking other elements. Atrophy near the growing point may be boron deficiency. Insufficient calcium causes the plants to grow weak and the female flowers are not full.
3. Countermeasures. Avoid the use of large amounts of potassium and nitrogen fertilizers at one time; timely watering to ensure adequate water supply; an emergency measure for calcium deficiency is to spray the leaves with 0.3% calcium chloride aqueous solution twice a week.
Fourth, iron deficiency disease
1. Symptoms. In addition to the new yellow leaves of the plant veins, the veins of the plants are gradually losing their green color, and the leaves of the lateral vines have the same symptoms.
2. Diagnosis points. The movement of iron in the plant body is small, so the leaves near the growing point begin to appear yellow. The new leaves have yellowing between the veins of the new leaf, gradually yellowing the whole leaf, but no symptoms of necrosis appear between the veins. If yellow leaves are found and iron is added in time, green leaves can be grown above the yellow and white leaves. Iron-deficient muskmelon leaves are bright yellow, with normal margins, and do not stop developing. Symptoms of the plant rhizosphere soil alkaline, there may be iron deficiency. The root absorption function is not good, resulting in decreased ability to absorb iron, prone to iron deficiency symptoms; plant leaves appear spotted yellow, or the whole leaf uniform yellowing, if the whole leaf yellowing is iron deficiency, if the upper If the leaves are spotted yellow, it may be a viral disease.
3. Countermeasures. Prevent alkalinity in the soil, pay attention to the management of soil moisture and prevent over-drying and excessive humidity. Emergency measures include spraying foliar with 0.1%-0.5% ferrous sulfate aqueous solution, or irrigating 50ppm aqueous solution of chelated iron salt. 100 ml.
Fifth, boron deficiency syndrome
1. Symptoms. The internodes near the growing point are significantly shortened. The upper lobe curls to the outside, and the leaf margin turns brown. When the upper lobe veins are carefully observed, there is atrophy. The fruit surface appears lignified.
2. Diagnosis points. Boron deficiency In an acidic sandy loam, an excessive amount of calcareous fertilizer is applied at a time, and boron deficiency disorders are prone to occur. The soil drying affects the absorption of boron and is prone to boron deficiency. The application amount of soil organic fertilizer is small, and the boron deficiency occurs in the soil where the soil pH is high. The application of too much potassium fertilizer affects the absorption of boron and is prone to boron deficiency.
3. Countermeasures. Boron is known to be deficient in soil, and boron fertilizer can be applied in advance; timely watering to prevent over-drying of the soil; do not use excessive calcareous fertilizer (high-calcium fertilizer), apply enough organic fertilizer, and improve soil fertility; emergency measures can be foliar spray 0.12 %-0.25% borax or boric acid in water.
Sixth, sulfur deficiency
1. Symptoms. There was no abnormal growth in the whole plant, but the leaf color of the upper and middle leaves turned yellow.
2. Diagnosis points. The deficiency of sulfur yellowing leaves is similar to the symptoms of nitrogen deficiency, but the location of the symptoms is different. The upper leaf is yellowing to sulfur deficiency, and the lower leaf is yellowing to nitrogen deficiency. The symptoms of upper lobar yellowing are similar to those of iron deficiency. Iron deficiency veins have obvious green color and yellow veins between veins. The sulfur-deficient leaf veins are chlorotic, but the leaves do not appear to be curled, leaf margins are dead, and plants are short.
3. Countermeasures. Apply sulfate-containing fertilizers such as potassium sulfate.
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