Vegetables died at seedling stage, and root rot was found only after pulling out. How to treat it?

In the process of vegetable planting, it is one of the common phenomena that root rot causes seedling death. In order to fundamentally solve the problem, it is necessary to find out what causes the death of seedlings by root rot, so as to fundamentally solve the problem. Next, I will talk about the main causes and control measures of root rot in vegetable seedling stage in detail.

A, retting dead seedlings

1. Causes of dead seedlings after retting

The dead seedlings of retting roots mostly occur in the early stage of seedling development. When the soil humidity of seedbed is too high due to excessive watering and other reasons, or when it encounters continuous rain and snow, the weather with low temperature and less sunshine lasts for a long time. Due to the lack of oxygen in soil, the normal respiration and nutrient absorption of roots are inhibited, which will lead to the death of seedlings.

2, retting dead seedlings prevention and control measures

Dead seedlings caused by retting roots can be prevented from the following aspects:

Choose sandy loam land with high and dry terrain, convenient drainage, fertile soil and good air permeability as seedbed, and the previous crop had better not be a vegetable crop. Improve the technical level of seedling raising and control the temperature and humidity in the shed. In case of low temperature and weak light, measures such as artificial warming, supplementary light and intertillage should be taken to make the soil well ventilated and keep moisture. In addition, we can absorb water and reduce humidity by spreading fine dry soil and plant ash. Proper application of active calcium and potassium fertilizer can improve the disease resistance of seedlings. Second, burn the roots and kill the seedlings.

1, causes of root burning and seedling death

Seedbed soil fertilization is unreasonable, water is insufficient or the covering thickness does not meet the requirements. Especially after the application of immature organic fertilizer, if the organic fertilizer is watered too much, the soil temperature will rise sharply during fermentation, generating a lot of heat, leading to root burning. In addition, uneven mixed fertilizer irrigation and uneven bed edge surface will also cause root burning and seedling death.

2, root burning and seedling death prevention measures

The organic fertilizer in seedbed soil must be fully decomposed before it can be used, and the application of nitrogen fertilizer should not be excessive. Fertilizer should be applied sparingly in plant ash, and mixed with seedbed soil. When dividing seedlings, the soil of the seedbed should be compacted and leveled, and the seedbed should be watered and permeable. After sowing, cover the soil properly to eliminate the root burning factor of the soil, and water it in time at noon on a sunny day after seedling emergence. Third, freeze and kill seedlings.

1. Causes of freezing injury and seedling death

When extreme weather such as cold current and low temperature comes, it is impossible to increase the plastic film in time, especially when the ground temperature is too low, resulting in the death of seedlings from freezing injury; Or the seedling dividing time is unreasonable, the seedbed temperature is too low, and the seedlings cannot take root after dividing, resulting in the death of seedlings.

2, the prevention and control measures of frozen seedling death

Pay attention to the weather forecast during seedling raising. In case of extreme weather changes, increase the plastic film in time and try to keep it dry to prevent it from getting wet by rain and snow and reduce the heat preservation effect. Manual control, temperature control and humidity control are adopted. Reasonable increase of light, promotion of photosynthesis and nutrient accumulation of vegetables, proper control of watering, rational application of phosphorus and potassium fertilizer, increase of soil temperature of seedbed, guarantee of temperature requirements of seedlings and improvement of stress resistance. Fourth, improper seedling separation causes seedling death.

1. Causes of improper seedling division and seedling death

When dividing seedlings, too many seedlings are picked at one time, which makes the milk seedlings lose too much water and it is difficult to recover and die; The seedlings themselves do not develop well before seedling division, and the seedlings are divided too late, which leads to weak roots and the seedlings will die.

2. Preventive measures for improper seedling separation and seedling death

Try to avoid damaging the root system when raising seedlings, and let the seedlings bring more bed soil, and the number of seedlings together should not be too much. The seedlings are wrapped with wet cloth to prevent excessive water loss, and the seedlings with few roots, broken roots and weak diseases should be carefully picked out when they are raised. It is beneficial to improve the survival rate of seedlings to divide seedlings into small ones without dividing them into large ones. Divide the seedlings on sunny days. V. Root rot caused by diseases

Root rot, Fusarium wilt, blight and other diseases occurred in vegetable seedling stage.

1, causes of disease and seedling death

The main factors causing the disease are improper soil temperature, humidity, light and seedbed management. Too much watering or too much rain causes serious diseases; Generally, when the soil temperature of vegetable seedbed should be stable above 20℃, the seedlings will emerge quickly, grow vigorously, have strong disease resistance and light disease. There are many rainy and snowy days in the seedling stage, insufficient illumination, weak seedling growth, poor disease resistance and serious diseases; Improper management of seedbed, such as sowing too early, too dense, untimely spacing between plants, too hidden seedbed, etc. , are easy to cause disease.

2. Prevention and control measures of disease and seedling death

Choose sandy loam land with high terrain, dry, convenient irrigation and drainage, fertile soil and good air permeability as seedbed, and it is best not to be a vegetable crop in the previous crop. Manure for seedbed should be sterile fertilizer decomposed at high temperature. Do a good job in seed disinfection and germination. Once the diseased plants are found in the seedbed, they should be sprayed with appropriate chemicals immediately. Be sure to pay attention to the dosage of drugs when using, so as not to cause drug harm. Six, root rot caused by pests

When underground pests such as grubs, grubs and earthworms occur in large quantities, they cause harm and seedling death. You can choose the corresponding pesticides to kill insects. Also pay attention to the dosage of the medicine.

The above are the causes and preventive measures of seedling death caused by root rot in vegetable seedling stage. We can see that except for pests, it is basically caused by improper management at seedling stage. Therefore, in the seedling stage, fully understanding the growth attributes of vegetables and improving the field management level are the main ways to prevent the dead seedlings.