The growth and development of vegetables are inseparable from water at all stages. Scientific water management is an important cultivation technique for obtaining high-yield and high-quality vegetables.
The photosynthesis of vegetables, the absorption of mineral nutrients by roots, the transport and accumulation of organic nutrients, and other physiological and biochemical processes require water participation.
Water demand for different types of vegetables
â— Cabbage, green leafy vegetables, cucumbers in melons, small radishes in root vegetables
This type of vegetable is a type that has a large water consumption and a weak water absorption. The leaf area is large, the tissue is tender, the roots are shallow, and the air and soil moisture are required during growth and development, and the demand for water is large.
When cultivating the land, pay attention to selecting soil with good water retention and timely irrigation. It grows well in the wet and frozen season, with high yield and good quality.
â— melons (referring to watermelon, cantaloupe, bitter gourd, etc.) vegetables
These kinds of vegetable leaves are large and nicked, and some leaves have velvet hair, which can reduce the transpiration of water, and have developed root system, deep into the soil, can absorb the bottom water of the soil, and have strong drought resistance. Generally, the stems and leaves are luxuriant, the leaf area is quite large, the fruit is thick and fleshy, and the water consumption is high. Especially after fruit setting, the fruit develops rapidly and needs more water. If the drought persists, it will not form timely malformation.
The loofah in melons is the most resistant to moisture and can continue to grow after flooding. According to the measurement, the amount of transpiration of 1g of dry matter in watermelon is 700g, which is higher than that of ordinary vegetables. Watermelon is suitable for sunny and hot dry climate, and leaves do not show snoring because its cell protoplasm has high tolerance to water shortage, but it still needs to pay attention to irrigation.
â— Onions and garlic, asparagus in perennial vegetables, etc.
The leaves of this kind of vegetables are cylindrical, band-shaped, and pseudo-leaf, the leaf area is very small, the leaf surface is less transpiration, and the root absorption is weak, so higher soil moisture is required, especially in the stage of edible organ formation. It is also necessary to keep the soil moist.
â— Vegetables such as solanaceous, root vegetables, beans, etc.
Compared with cabbage and green leafy vegetables, the leaf area is small, the tissue is hard, the leaves are often velvety, the water consumption is small, and the water absorption is medium. The root system is more developed than cabbage, but it is not as good as watermelon and pumpkin, so the drought resistance is not strong.
Beans and vegetables are more drought-tolerant, the seeds are rich in protein, and the water is too much after sowing, and the rot is lost. The amount of water should be less when flowering, and the water should be sufficient after podding. The farmer said that "dry flower wet pods" is the reason.
â— Aquatic vegetables
It is a type of vegetables that consumes very little water and has a weak ability to absorb water, such as white, sputum, and sputum. Plants should be immersed in water in whole or in part to grow. The stems and leaves are tender, the transpiration is vigorous under high temperature conditions, the root system is underdeveloped, and the root hair is degraded, so the absorption is very weak. To grow in ponds or paddy fields that maintain a certain water level.
The demand for water in vegetables at different times
Generally, there must be sufficient water when the vegetable seeds are germinated.
At the seedling stage, the root system is small, the water absorption is not much, and the soil moisture is strict, and the watering should be controlled.
All kinds of vegetables should be watered before and after transplanting, and more water should be poured when forming soft and juicy edible organs.
When flowering, the water should not be too much. When the fruit grows, it should be watered a lot. The nutrient storage organs should be strictly controlled before watering.
Keep the seeds dry when they are ripe, otherwise the quality of the seeds will be affected.
Vegetable demand for air humidity
The normal growth and development of vegetable crops requires not only proper soil moisture, but also suitable air humidity. According to the difference in the relative humidity requirements of vegetables, it can be roughly divided into the following four types.
Vegetables such as cabbage, green leafy vegetables, and aquatic vegetables: The relative humidity of the air is required to be 85% to 90%.
Potatoes in the yam, cucumbers in the melons, root vegetables (except carrots), broad beans in beans, peas, etc.: The relative humidity of the air is required to be 70% to 80%.
Vegetables such as kidney beans, cowpeas, and lentils in solanes and beans: The relative humidity of the air is required to be 55% to 65%.
Vegetables such as watermelon, melon, pumpkin, and onion and garlic in melons: The relative humidity of the air is required to be 45% to 55%.
Precautions for watering vegetables in greenhouses
â— Pay attention to watering time
The greenhouse is best to be watered in the early morning on a sunny day. At this time, the ground temperature is close to the water temperature. After watering, the root system is stimulated and easy to adapt. At the same time, the ground temperature rises quickly and there is enough time to remove the moisture in the shed. Watering in the afternoon will cause the ground temperature to suddenly change, affecting the physiological functions of the root system. It is not advisable to water in the afternoon, evening or rain or snow.
â— Pay attention to the amount of watering
Watering the greenhouse, it is not suitable for flooding. First, large-water flood irrigation wastewater will reduce the ground temperature, cause fertilizer loss, hinder the absorption of fertilizer by roots, and affect its normal growth and development. Second, flooding of large water is easy to increase the humidity of the air in the shed, and high humidity is an important factor in inducing various diseases.
â— Contradiction of warming and dehumidification
On the day of watering vegetables in winter and spring greenhouses, the ground temperature should be restored as soon as possible, the greenhouse should be closed, the indoor temperature should be raised, and the ground temperature should be raised with high temperature. After the temperature rises, it is necessary to ventilate and dehumidify in time to reduce the indoor air humidity to a suitable range to ensure the healthy growth of the crop.
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