In wintering cultivation of cucumber, "yellow ring leaf" generally appears, affecting the yield and economic benefits. This phenomenon is not caused by infectious diseases and is generally a physiological disease.
Symptoms occur more in the lower leaves. The edge of the beginning of the blade appears yellow, and the back edge develops along the edge of the blade toward the inside of the blade. About 2 to 3 centimeters in width appears chlorotic, followed by a yellowish green, which surrounds the leaf one week. It is called "yellow ring leaf." In severe cases, the yellow ring scorch and the leaves die.
Prevention methods increase the temperature in the solar greenhouse. Improve the structure of solar greenhouses, such as thickening walls; dig cold-proof ditch; increase the height of greenhouses, increase the angle of incidence of sunlight, increase the incidence of sunlight, and increase the utilization of sunlight; use plastic films with increased temperature, etc.; Grass seedlings; double-layer covering with non-woven fabrics in the greenhouse; hanging light curtains on the northern side of the greenhouse.
Deeply to the ground. Turning the soil deeper than 30 cm has two benefits: First, the soil is loose, the roots are strong, and the absorption capacity is enhanced. Second, the soil is loose, and the water storage is strong. When the temperature is high, the soil can accumulate more. The moisture reduces the number of watering when the cold winter temperature is low, and prevents the groundwater from being overheated by too many times. In order to solve the difficulties of turning over the greenhouse, we can use 200 grams of soil conditioner without deep plowing, add 100 kg of water, and spray an acre of ground. After spraying, loose soil of 50 to 100 cm depth can be loosened.
Increase the application of organic fertilizer, moderate application of ammonium nitrogen fertilizer. When using chemical fertilizers, pay attention to the proper combination of nitrogen, phosphorus and potassium. In the lower temperature season, potassium dihydrogen phosphate 0.2% solution was sprayed every 3 to 5 days to supplement the potassium supply of the plants. At the same time, it can increase the concentration of the cell fluid and enhance the ability of the plants to resist cold.
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