What impact will continuous rainy days have on vegetable planting? How to deal with ensuring output and quality?
There are many continuous rainy weather this year, and vegetables are the crops most affected by the weather. Judging from the feedback from vegetable farmers, without such continuous rainy weather, both the growth of vegetable plants and flowering and fruit setting will have many adverse effects, making production management more difficult. So, what impact do rainy days have on vegetable production? How to deal with it?
Adverse effects of continuous rainy weather on vegetable growth
As long as continuous rainy weather lasts for more than 3 days, it will have varying degrees of impact on the growth of vegetables.
1. Leggy plants and weak flowers
In continuous rainy weather, leggy plant growth and weak flowers are particularly common in vegetables. This is mainly because under high temperature and low light conditions, plants will appear to be leggy. This leggy growth is caused by excessive nutrient consumption and accumulation of organic nutrients. In a low-light environment, the organic nutrients synthesized by photosynthesis of vegetable plants are inherently insufficient, and most of them are supplied to the vegetative growth of the plants. At the same time, as long as the plants appear to be leggy, the flowers will be weak.
2. Insufficient supply of organic nutrients
Organic nutrients are produced by leaves through photosynthesis and are the prerequisite for vegetables to grow plants and fruits. Without light, photosynthesis will be weakened and less organic nutrients will be produced. As long as the supply of organic nutrients is insufficient, many physiological diseases will occur. For example, cucumbers, pointed melons, and curved melons; tomatoes that do not swell or have hollow fruits; eggplants and peppers that do not swell after being seated; beans with drum beans, etc., are all physiological diseases. The poor commercial quality of vegetables is directly related to the insufficient supply of organic nutrients.
3. Vegetables suffer from nutrient deficiencies
When the supply of organic nutrients is insufficient on cloudy days, the key deficiencies are four elements: calcium, magnesium, boron, and iron. Calcium-deficient tomato navel rot, fruit cracking, and bud blight are all directly related to calcium deficiency. Calcium deficiency and boron deficiency in cucumbers will cause curved melons and scorched edges at the growing points. The most typical symptom of iron deficiency is after a cloudy day. , one sunny day yellow heads appeared on the entire growing point. These deficiencies all have a premise, which is poor stress resistance. Under this premise, simply supplementing boron and calcium may not necessarily work. Therefore, for deficiencies, it is extremely important to supplement medium and trace elements while improving stress resistance. .
4. Plant wilting
When a plant wilting appears on a sunny day after a cloudy day, the first thing to consider is whether there is a root problem. There are three main reasons for plant wilting: Physiological root retting or root diseases: On cloudy days, due to less organic nutrients being synthesized, most of them are supplied to the growth of the plant, and the organic nutrients allocated to the root system will be reduced. decrease, resulting in root necrosis. Root diseases: Root diseases can also cause plant wilting. Fungal root diseases include root rot and blight; bacterial root diseases include canker, pith necrosis and bacterial wilt. It is necessary to judge which disease it is based on the symptoms of wilting, including the performance of the marrow, vascular bundles, etc., and then symptomatic prevention and treatment can be achieved. Physiological water loss: After several days of continuous cloudy days and a sudden sunny day, the leaves require a particularly large amount of transpiration. The water supply absorbed by the roots cannot meet the transpiration needs of the leaves. At this time, the entire plant will lose water. Withered.
No matter what kind of situation causes wilting, corresponding countermeasures can only be taken after a clear judgment.
5. Major outbreaks of diseases
Continuous rainy days can easily lead to major outbreaks of diseases that require a high-humidity environment. For example, on a cloudy day after a rainy day in tomatoes, fungal diseases such as gray leaf spot, bacterial diseases such as brown spot and leaf spot, and diseases of medium temperature and high humidity such as late blight; diseases such as anthracnose and target spot that occur in cucumbers under high temperature and high humidity conditions Diseases, downy mildew and leaf blight occur frequently when the temperature drops; eggplant blight and leaf blight occur in high temperature and high humidity; pepper leaf blight, leaf spot and anthracnose in high temperature and high humidity; anthracnose, brown spot and anthracnose in beans under high temperature and humidity Cotton disease.
Response measures for vegetable planting after continuous rainy weather
After clarifying the impact of continuous rainy weather on vegetables, let’s talk about the countermeasures below.
1. Strengthen the control of vigour, and follow up the promotion of flowering
The prerequisite for promoting flowering is to control vigour. If the plant is leggy, no matter how you promote flowering, it will be useless. The nutrients produced by the leaves are called organic nutrients. They are produced during the day and run in the first half of the night. Where they run depends on the vegetable's judgment of the external environment. When the vegetable senses that the outside temperature is relatively high, it will exert force to transport it to the plant. When the temperature feels relatively high, the nutrients produced by the leaves are called organic nutrients. If it is low, such as in winter, the first source of nutrients is the fruit. Therefore, if you cannot control the growth well, you will not be able to promote flowers no matter how much you do.
Therefore, after continuous rainy days, it is recommended to spray triflutriol + medium and trace elements + biostimulants. The dosage of triflutriol should be controlled according to the growth of the plant. If the plants are still leggy after using tetraconazol, you can add potassium dihydrogen phosphate or the hormonal agent methylpiperium to control overgrowth and promote flowering at the same time.
2. Improve stress resistance and supplement organic nutrients after sunny days
After cloudy days, improve stress resistance while supplementing organic nutrients to alleviate plant wilting and physiological water loss. Do it one day in advance or on a sunny day, because the supply of organic nutrients in vegetables is insufficient on cloudy days. Therefore, organic nutrients must be supplemented to alleviate nutrient deficiencies. It is recommended to spray plant-derived auxins + plant-derived amino acids through the leaves.
3. Treatment of nutrient deficiencies
The premise of conditioning for nutrient deficiencies is to improve stress resistance. After the rainy day, if the new leaves at the growth point of the plant turn yellow, it is recommended to spray plant-derived amino acids + chelated iron on the leaves; if there are navel rot, scorched leaves, cracked fruits, etc., spray plant-derived amino acids + Medium and trace elements.
4. Roots must be nourished after cloudy days
Many of our vegetable farmer friends have a misunderstanding that plants will wilt after a continuous cloudy day. Supplementing nitrogen, phosphorus and potassium can make the plants wilting. Quickly resume growth, but as everyone knows, the root system of the plant is at its weakest at this time, and supplementing with a large amount of elemental fertilizers will only increase the damage to the root system. Therefore, as long as there are continuous cloudy days for more than 3 days, when watering again on sunny days, you must first stop applying nitrogen, phosphorus, and potassium fertilizers, whether they are compound fertilizers or water-soluble fertilizers. The first priority at this time is to nourish the roots. . There are two situations for root maintenance after cloudy days: Plant wilting: Plant wilting occurs after continuous cloudy days. In addition to physiological water loss, it is mainly caused by root retting or root diseases. Therefore, as long as the plants appear wilted, it is recommended not to water them first but to irrigate the roots first. The purpose of root irrigation is to sterilize and nourish the roots at the same time. Use root-nurturing fertilizer + trichloroisocyanuric acid to irrigate the roots, and use strong oxidants to reduce the number of pathogenic bases. The plant does not wilt: If the plant does not wilt, it means there is no root disease and you can just nourish the roots.
5. Prevention of diseases
As soon as the cloudy days end, diseases will begin to occur. Therefore, after the cloudy days are over, it is necessary to prevent the disease in time. Do not wait for the disease to become popular before carrying out prevention and control. By then it will be too late. It is recommended to spray difenoconazole + dicyanoanthraquinone + kasugamycin + propamocarb hydrochloride, so that both fungal and bacterial diseases can be well prevented. If the disease has already occurred, choose the corresponding therapeutic agent for treatment.
Continuous rainy weather will have many adverse effects on the growth of vegetables. By taking targeted countermeasures, these potential harms will be reduced to a minimum, thereby ensuring the yield and quality of vegetables.