In the winter, the greenhouse is used to grow cucumbers. It often encounters cucumbers with good growth in the early stage. When the melons are ripened or the melons are about to be meloned, some of the melon seedlings gradually or suddenly shrink, and the whole plant will die. The author goes to the countryside to investigate agriculture. When you are in production, it is heartbreaking to see this symptom.
Why do greenhouse cucumber seedlings appear to be wilting? From the situation of a large number of investigations, there are several reasons for the formation. First, the concentration of fertilization is too large, especially when applying chemical fertilizer near the root and neck of cucumber, it is easy to burn the melon seedling; the second is to apply organic fertilizer with higher nitrogen content. In the process of decomposition, ammonia gas is generated. When the temperature rises, the concentration of ammonia gas is too large to cause wilting and dead seedlings; the third is continuous rainy or snowy after the snow, because the melon seedlings often cause wilting or death; The high temperature release air is too large, or the film is damaged, the cold wind invades, causing the wilting dead seedling; the fifth is that the root nematode damage will also cause shrinking dead seedlings. Among the above various reasons, some are caused by human error, and some are extended by physiological diseases, but improper application of fertilizer and water should be the main reason. The following corresponding techniques should be used to prevent it.
First, a reasonable operation of fertilizer and water. The root system of cucumber is relatively developed, but most of it is concentrated in the soil surface. In order to promote early roots and multiple roots, prevent fertilizer and water operation errors from inhibiting the growth of root populations, attention should be paid to fertilization and watering: first, use fully decomposed organic fertilizer or bio-organic compound fertilizer as base fertilizer; second, control the amount of base fertilizer. In particular, the bio-organic compound fertilizer with high nitrogen content should not exceed 75 kg per acre. The third is to use the quick-acting nitrogen fertilizer to top dress, one should be applied deep, and the second should be slightly away from the cucumber root; When planting melon seedlings, plant less water, and then pour back to Qingshui as appropriate. The temperature is low, the soil moisture is high, encountering rainy weather, less pouring or not pouring back to Qingshui; fifth, when the temperature is high and continuous drought, only in the case of continuous drought The water in the shed is infiltrated, and it is not possible to flood the water.
Second, scientific control of the shed temperature. Generally, it is not ventilated at the initial stage of planting. It is kept at 25 °C ~ 30 °C during the daytime, and 12 °C ~ 15 °C at night, not less than 10 °C. As the melon seedlings continue to grow, it is necessary to adjust the temperature and temperature in time. One can prevent the occurrence of diseases, the second can avoid the aging of plants, and the third can supplement carbon dioxide. However, the regulation of temperature must be conducive to the growth of cucumber. Generally, the temperature rises to 30 °C during the daytime, and the membrane is closed when it drops to 28 °C in the afternoon. The nighttime temperature during the melon period should not be lower than 12 °C.
Third, strengthen the protection of greenhouses. First, often divert the gully around the shed to keep the channel open, so that it can be drained in time, especially to quickly filter the water; second, check whether the shed film is damaged or exposed every day, pay attention to repair, keep warm and warm Third, before the coming of the wind, cover the straw curtain and lock the rope to prevent the film from being damaged.
Fourth, prevent underground pests and diseases. The nematode disease causing the wilting of cucumber is caused by underground nematodes. Root-knot nematodes are generally distributed in the soil layer of 3~9 cm on the surface. The roots of the affected roots form nodules and gradually enlarge. After the root tissues are destroyed, the absorption and transportation of fertilizer and water are hindered, making the plants short, the leaves turn yellow, and the leaves are swollen or severe. death. For the prevention method, Yangda organic complex fertilizer granules with controllable pests and diseases can be used, 25 kg per mu as base fertilizer, or 1:300 times liquid of Yangda organic complex fertilizer liquid fertilizer, sprayed 3~4 times or Once rooted, it can inhibit root-knot nematode disease and promote cucumber yield.
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