What reason is the wheat seedling yellowing? If you don't deal with it in time, the leaves will dry.

The common causes of yellowing of wheat seedlings are improper sowing, drug damage, fertilizer damage, diseases and insect pests and lack of elements, and most of the diseases and insect pests of wheat seedlings are sheath blight, total erosion disease, grub, golden needle worm and mole cricket, etc. element deficiency is mostly phosphorus deficiency, nitrogen deficiency, potassium deficiency and so on.

After the emergence of wheat seedlings in spring and winter, there will be sparse seedlings, weak seedlings, yellow seedlings, withered seedlings and so on, which are caused by improper sowing, drug damage, fertilizer damage, diseases and insect pests, lack of elements and so on.

1. Improper sowing

The main results are as follows: 1. The excessive density during sowing can easily lead to the large population of wheat, which will affect the photosynthesis of wheat, and the nutrients can not be supplied in time, which will eventually lead to the yellowing of leaves.

2. If the distance between each wheat seedling is too dense, there will be competition for fertilizer, water, light and so on, which will eventually lead to the weakness and yellowing of wheat seedlings.

Remedy: if the land is too dry, it should be watered in time to promote the normal growth of wheat seedlings. Or if the density is too dense, it is necessary to divide the seedlings manually, so as to increase the ventilation and transmittance, deep ploughing and cutting roots to reduce the absorption of water and fertilizer and promote the growth of strong seedlings.

II. Drug damage

The main results are as follows: 1. When agitating with pesticides and wheat seeds, excessive amount of pesticides will cause yellow death of leaves of wheat seedlings.

2. Herbicides will remain on the land where other crops have been planted, and wheat can not be planted immediately. If planted immediately, the wheat seedlings will turn yellow.

Remedy: if the problem is not serious, don't worry about it. After the secondary root grows, the wheat seedlings will naturally change from yellow to green. If the problem is serious, it should be watered to remedy it and loosen the soil after watering.

III. Fertilizer damage

The application of farm manure and bean cake to wheat seedlings is not completely mature organic fertilizer, or too much seed fertilizer is used, and the position of fertilization is very close to wheat seeds, which will cause wheat seedlings and seeds to be easily burned by fertilizer, which will directly lead to the yellowing of leaves or leaf tips.

Remedy: watering and leaching should be carried out every week and continuously irrigated 1-3 times according to the specific fertilizer damage.

IV. Diseases and insect pests

There are many diseases and insect pests that make wheat leaves yellow and withered at seedling stage, which are generally sheath blight, total erosion disease, grub, golden needle worm and mole cricket.

1. Sheath blight: in the period of wheat seedling, it harms the underground stem of wheat, hinders the transport of water and nutrients, develops gradually with time, and finally leads to the yellowing of the leaves of wheat seedlings.

2. Total erosion disease: when the wheat seedling is damaged at the seedling stage, the primary root and the base of the root will turn dark brown, the upper leaves of the surviving wheat seedlings will become lighter, the leaves at the bottom will be yellowed, and the wheat plants will become dwarfed. the root can be pulled out easily.

3. Mole cricket: in autumn, the young roots of wheat are bitten off or bitten into hemp, resulting in the death of wheat seedlings, and can also move on the surface of the soil, separating the roots and soil of wheat seedlings, resulting in the yellowing of wheat seedlings.

4. Grub: the peak of its damage is from September to October in autumn and from April to May in spring. It will bite off the rhizome of wheat seedlings and cause the seedlings to yellowing and withering.

5. Golden needle worm: in the larval stage, by biting the germinated wheat seeds and the rhizome of wheat, it can also drill into the intersection of seeds or rhizomes, resulting in the formation of withered seedlings of wheat seedlings, resulting in the yellowing and death of the whole seedling.

6. Root rot: root rot is easy to occur in wheat seedling stage, which will make wheat seedlings yellow. when it becomes serious, it will wither and rot all the roots.

Remedy: after the occurrence of root rot, 70% methyl topiramate wettable powder 800-1000 times solution can be used for along-ridge root irrigation.

5. Lack of elements

1. Nitrogen deficiency: it will lead to short and weak wheat seedlings, few tillers and weak tillers, which can easily lead to yellowing of leaves, withering of leaf tips and yellowing of old leaves.

Remedy: you can apply about 10-15 kg of urea per mu, or 7-12 kg of ammonium bicarbonate per mu, and if there is still nitrogen deficiency after turning green, you can continue to apply about 15 kg of urea per mu, or when the wheat seedlings turn yellow, spray 2% urea on the leaves, and apply it again after an interval of about a week.

2. Phosphorus deficiency: the secondary roots and tillers of wheat seedlings are very few, the color of the leaves is dark green, the leaf tips are yellow, the newly grown leaves will be turquoise, and the leaf tips are purplish red, which will eventually lead to fewer small grains in the spikes of wheat.

Remedy: after the occurrence of phosphorus deficiency, about 7-10 kg of diammonium phosphate or 10-20 kg of calcium superphosphate can be applied per mu, or 80 kg of 3% 5% calcium superphosphate aqueous solution can be sprayed on the leaf surface per mu. Spray once every other week to 10 days, even 2 to 3 times.

3. Potassium deficiency: generally, it starts yellowing from the tip of the old leaf of wheat, and then goes all the way down the vein. The part of the macula is obvious and will be mosaic yellowing. In the later stage, the yellowed leaves will stick to the ground, and the stems of wheat plants are small and thin. Lodging and premature senility are easy to occur.

Remedy: if remediation is carried out at the wheat seedling stage, about 5-10 kg of potassium chloride or potassium sulfate can be applied per mu, or about 30-50 kg of plant ash per mu. If remedied in the middle and later stages of wheat growth, 10% plant ash solution can be sprayed on wheat leaves per mu, once every other week, 2-3 times.

VI. Other reasons

The ability of soil fertilizer conservation is poor, the soil is barren, and the base fertilizer is insufficient when sowing seeds. Wheat seedlings will yellowing because of the long-term lack of fertilizer.