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With the improvement of the planting income of large cherry facilities in greenhouses, the planting area in various places continues to increase; however, in recent years, drought and little rainfall have led to high summer temperatures, and long light hours have resulted in an increase in large cherry deformed fruits (twins or even multiples), affecting the yield of fruit trees; at the same time Because fruits and vegetables increase labor costs. Experiments have found that when the light intensity reaches 100,000 LUX or more, and the ambient temperature reaches 35 degrees for 5 hours for several consecutive days, the incidence of deformed fruit increases significantly; form. Therefore, in the temperature-sensitive period of flower bud differentiation, if extremely high temperature is encountered, measures such as covering the top of the tree for short-term shading to reduce the temperature and solar radiation intensity can effectively reduce the occurrence of double pistil flower buds, thereby reducing the deformity in the following year. the occurrence of fruit. The use of shade nets to shade and cool the big cherries in the facility has become a must-have operation every summer. In summer, in order to prevent high temperature obstacles, fruit and vegetable farmers often use the method of shading to reduce the temperature in the shed. In actual production, various shading methods are used, some are covered with black and silver-gray shade nets to cool down, and some are poured mud and ink on the shed film to cool down. These different shading methods definitely have different shading effects.
   Scientific and reasonable selection of sunshade nets
The main function of the shading net is to block strong light and reduce the temperature of the greenhouse. However, if you choose an inappropriate shade net, it will not only cause the plants to grow leggy, but also be unfavorable for flowering and fruit setting. Therefore, the screen must be selected scientifically and reasonably.
1. Do not judge the pros and cons of shade nets by color: the shade nets currently on the market are mainly black and silver-gray. The black shade net has high shading rate and rapid cooling, and is suitable for short-term coverage in fields that require careful management in hot summer; the silver-gray shade net has a low shading rate and is suitable for light-loving vegetables and long-term coverage.
2. The quality of the sunshade net is not determined by the color, the color of the sunshade net is added in the process of raw material manufacturing. Therefore, different vegetables should choose shading nets with different colors and different shading rates. For example, tomato is a light-loving crop. As long as it meets the sunshine time of 11 to 13 hours, the plants will grow robustly and bloom earlier. While the effect of light time on tomatoes is less important, light intensity is directly related to yield and quality. Insufficient light can easily lead to malnutrition, leggy growth, and reduced flowering. The light saturation point of tomatoes is 70,000 lux, and the light compensation point is 30,000-35,000 lux. Generally, the light intensity at noon in summer is 90,000-100,000 lux.
3. The black shading net has a high shading rate of up to 70%. If the black shading net is used, the light intensity cannot meet the normal growth requirements of tomato, which is easy to cause leggy tomato and insufficient accumulation of photosynthetic products. Most of the silver-gray shade nets have a shading rate of 40% to 45%, and a light transmittance of 40,000 to 50,000 lux, which can meet the normal growth needs of tomato. So tomatoes are best covered with silver-gray shade nets.
4. In order to achieve different shading rates, each shade net has different weaving densities. There are generally three types; the shading rate of two needles is 45%; the three needles are 70%; and the four needles are 90%. Therefore, when choosing a shade net, the shade net of that density should be selected according to the crops planted.
According to the growth characteristics of large cherry, its light intensity is the same as that of growing ginger, so it is recommended to use a 2-needle shade net.
   Avoid the following mistakes when choosing:
1. Fruit farmers who use shading nets are very easy to buy nets with higher shading rates when purchasing shading nets. They will think that the higher shading rates are cooler. However, if the shading rate is too high, the light in the shed is weak, the photosynthesis of crops is reduced, and the stems are thin and leggy, which reduces the yield of crops. Therefore, the sunshade net must be selected according to the light intensity of the planted crops.
2. The heat shrinkage characteristics of the sunshade net are easily overlooked by everyone. In the first year, the shrinkage is the most, about 5%, and then gradually becomes smaller. As it shrinks, the shading rate also increases. Therefore, the thermal shrinkage characteristics should be considered when fixing with the card slot.
Original Nanguo Beixiang