How to coordinate the yellowing of leaves at the seedling stage of cotton, how to regulate the yello

Cotton leaves turn yellow at the seedling stage"scaled"Cotton deficiency"。The pale yellowish-green leaves of the seedlings belong to nitrogen deficiency.

Symptoms of nitrogen deficiency: the leaves of the seedlings are pale yellowish-green, which turn yellow with the growth of the plant, and often appear red of different shades later, and finally form brown, and the leaves dry up and fall off prematurely. Since the growth of the main stem (primary stem) is inhibited at an early stage, the plant is short and stunted.

The number of leaves and branches on the plant decreased, the fruit branches were few and short, and the formation of cotton bolls in the middle and upper parts was affected. Symptoms are likely to manifest in the seedling stage and flower boll stage.

Note: In reality, because the bottom fertilizer uses less nitrogen fertilizers such as urea, and the proportion of nitrogen demand at the seedling stage is high, the symptoms at the seedling stage and bud stage are more prominent. However, in the middle and late stages, excessive topdressing of urea leads to excess nitrogen, resulting in vigorous growth of plants.

Fertilization method: the first choice for topdressing nitrogen fertilizer is urea, the same amount of fertilizer, generally cotton fields can be topped once in the budding period. Foliar sprays can be applied in the early stage"Strong man"500 times + concentration of urea, 1% 3% diammonium phosphate aqueous solution can be mixed in the middle and late stages, and nitrogen and phosphorus can be supplemented.

There are all kinds of trivial things to do. However, every morning, I find a cup of hot water at the head of my bed; Every morning, the food that I brought to class was packed into my school bag; Every afternoon when I got home from school, it was already 7 o'clock, and the hot dinner was already on the table; Before going to bed, I usually had a cup of hot water and a warm quilt, all of which I naturally accepted. These silent movements and actions have turned into wisps of clear water that flow into my heart, making me feel warm every time.

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There are many causes of yellowing, which can be physiological diseases (caused by the environment, such as light, fertilizers, water) and can be non-physiological diseases (caused by some pathogenic organisms, such as fungi, bacteria, nematodes) or insects (pests of stinging and sucking mouthparts).

Specifically, you have to see what causes it, and tell the landlord a simple identification method: if a large piece of cotton is yellow, and there is no spread of infection, it is a physiological disease, and the landlord can pay attention to water and fertilizer control. If there is a disease center and there is a phenomenon of spreading infection, and there is a mold layer or small black spots at the affected area, the fungal disease (treated with a pesticide such as 20% etherstrobin suspension).

If you can see the gaps in the damage of insects, or there are small mosquitoes like flying insects, it is a pest, and it is generally treated with a spray of imidacloprid or something.

The yellowing of cotton is generally caused by the environment (light, water, temperature), and the yellowing will be controlled if the environment is improved.

It may be cotton yellow wilt, spray with Zhuang Feng, and bring a little medicine to fight aphids in it.

<> cotton leaves are yellow, urea, potassium sulfate, potassium chloride and other fertilizers should be used. Due to the lack of nitrogen fertilizer and potassium fertilizer caused by the yellowing of cotton leaves, should be supplemented with top fertilizer, generally apply kilograms of urea and kilograms of potassium sulfate or potassium chloride per mu, and focus on the collapse of the difference before chemical control of the cotton field, 3-5 grams of water per mu with 40-50 kg of water evenly spray Hui round mist, which can control the excessive elongation of the upper fruit branches, strengthen ventilation and ventilation, and have the effect of preventing cotton leaves from yellowing.

If she's busy, she's either too dry, or she's thinking too much, so she's going to have a relationship.

The phenomenon of burnt leaves may be to give him some insect medicine when he is sick to see if it is useful.

**Cotton I think it is a physiological disease, the root system of high-temperature cotton is not good, or it is caused by high temperature evaporation after rain, you can spray some foliar fertilizer in the evening.

Most of the occurrence of cotton wilt occurs at 28 degrees Celsius, which is easy to break out.

If it is this temperature according to the blight**.

Nail cream can be used. Oxazalin plus pentachlor. Spray with fomidics or tetramycin or fludioxonil or Bacillus subtilis plus rooting agent.

At present, there is no effective agent that can prevent and control the occurrence of Verticillium wilt, and we must adhere to the measures of prevention and comprehensive prevention and control in production, and we must adapt measures to local conditions, sooner rather than later, in order to receive good results.

Do a good job of quarantine and protect disease-free areas. Quarantine is an effective measure to prevent problems before they occur. When transferring seeds, it is necessary to carry out the procedures for the allocation and quarantine of seeds. Cotton seeds in the sick area should be disinfected first, and the cotton seeds in the isolation area should be planted for one year to prove that there are no pathogens before they can be planted in the disease-free area.

Pesticides treat the seeds. 10 ml of fludioxonil suspension seed coating agent to 100 ml of water, stir evenly and mix 10 kg of cotton seeds, which has a good preventive effect on cotton seedling disease. In the new occurrence area of wilt and verticillium wilt, cotton seeds should be depiled with sulfuric acid, and then 50% carbendazim suspension kilogram to 50 kg of water, 20 kg of cotton seeds soaked at room temperature, 12 14 hours after fishing and drying until the seed sprouts are white and then sown, which can control the occurrence of wilt and verticillium wilt.

Scientific management of cotton. The first is to control the amount of fertilizer according to the law of cotton growth, that is, from the seedling stage to the budding stage (mid-to-late May and early to mid-June), less fast-acting nitrogen fertilizer and more slow-release calcium, magnesium, phosphorus and potassium fertilizer and organic matter fertilizer are applied, accounting for about 10% 15% of the total fertilizer amount; From budding to flowering stage (early June to early July), nitrogen, phosphorus and potassium fertilizers should be applied lightly and steadily, accounting for about 15% and 20% of the total fertilizer amount; From flowering to boll setting (early July to early August), nitrogen, phosphorus, potassium fertilizer and organic matter fertilizer should be reapplied, accounting for about 60% of the total fertilizer amount; From boll setting to flocculation period (mid to late August to early September), nitrogen fertilizer or cotton special compound fertilizer 5% (containing nitrogen, phosphorus and potassium 22% and 13%) should be applied according to local conditions.

Balanced fertilization. In the early stage of the disease, spray the diseased plants with agents such as dichlorfen.

I'm not familiar with cotton, for your reference! Thank you!

Is there a way to solve the phenomenon of yellow leaves in the early stage of emergence? This should be due to the lack of certain substances, I think this should be possible to add, this should be very good.

If the leaves like this are browned at the beginning of cotton emergence, it may generally be a lack of nutrients.

It must be too hot, right?

You can take a look. Is there something nearby? Disease. Is it too hot?

According to your description, it is possible that it is cotton wilt. Cotton wilt is a serious disease in cotton production, which has been more serious in the cotton area, and the dead seedlings are serious, causing greater damage and loss, so it is of great significance to seize the favorable opportunity and select effective agents to prevent and control cotton wilt.

1. Harmful symptoms.

Cotton wilt disease can occur from seedlings to adult plants, and the disease is most prevalent before and after budding. It can be summarized into 5 types: (1) Yellow reticulation type:

The veins of the diseased plants turn yellow, the mesophyll remains green, the leaves are partially or mostly yellow reticulated, and the leaves gradually shrank and wither. (2) Yellowing type: the edge of the leaf is partially or mostly yellowed, shriveled and withered.

3) Purple-red type: the leaves turn purple-red locally or partially, and the leaf veins are also purple-red, shrunken and withered. (4) Cover Ming quietly wilt type:

The leaves suddenly lose water, the leaf color becomes slightly dark green, the leaves become soft and thin, and the whole plant is green and dry and dies, but the leaves generally do not fall off, and the petioles are curved. (5) Shrinkage type: When there are 5-7 true leaves, most of the top leaves of the diseased plants are shrunken, deformed, dark green in color, shortened between nodes, shorter than healthy plants, and generally do not die.

The xylem of the rhizome section of the diseased plant turns black-brown.

Second, the incidence of the disease.

Cotton wilt mainly overwinters in diseased seeds, diseased plant residues, soil and manure. The transportation of seeds and fertilizer is the main cause of the disease in the new diseased area, and the agricultural operations such as farming, management and irrigation of cotton fields in the affected area are important factors for the close transmission. The roots, stems, leaves, and shells of diseased plants can grow pathogen spores when high humidity, which can spread with air currents and rainwater and infect surrounding healthy plants.

The onset of cotton wilt is closely related to temperature and humidity, generally the soil temperature begins to show symptoms at about 20, when the soil temperature rises to 25 -28, the peak of the disease is formed, when the soil temperature rises to more than 33, the disease is inhibited, and there is a temporary hidden disease, and when the soil temperature drops to about 25 in autumn, the second peak of the disease appears. In summer rainstorms or rainy years, the disease is severe due to the drop in soil temperature. Low-lying, heavy soil, alkaline, poor drainage, partial application of nitrogen fertilizer and application of unrotted bacterial fertilizer, continuous cropping of cotton fields, extensive tillage and cotton fields with many root nematodes reappear.

3. Prevention and control methods.

According to the growth and appearance of cotton in the former cotton field, combined with the application practice in recent years, the key measures for the prevention and control of cotton wilt are mainly as follows:

1. Strengthen cultivation management: on the basis of applying sufficient base fertilizer, increase phosphorus and potassium fertilizer to improve disease resistance, and apply aseptic net fertilizer. Fast-acting nitrogen fertilizer should be applied to the sedan block of the seriously ill field. At the same time, it is necessary to clear the ditch and manage the moisture, cultivate and weed and loosen the soil in time.

2. Chemical prevention and control: In the early stage of the disease, use 50 hundred grams, 20-30 grams or 25 hundred grams of 40-50 ml, or 30-40 grams (3-4 packs) of Shigao to 40-50 kg of water, or irrigate the roots into 500 times the liquid. The fields with heavier disease can be sprayed again every 5-7 days, or the roots are irrigated again, and at the same time, potassium dihydrogen phosphate solution plus 1 urea solution foliar spray is carried out every 5-7 days, 2-3 times in a row, and the disease prevention effect is more obvious.