After the spring temperature rises, the wheat gradually enters the turning green and the rising period. The phenomenon of yellowing and even death of the wheat seedlings often occurs. Failure to take timely measures to remedy will result in different degrees of reduction in production. There are many reasons for the yellowing of wheat seedlings. Commonly there are fertility deficiency, pest damage, low-temperature freezing damage, drought or waterlogging, etc., and attention should be paid to distinguish them and take remedial measures in a targeted manner.
Nitrogen deficiency showed field yellowing of wheat seedlings, thin seedling growth and poor tillering. Can apply urea 5 to 10 kilograms per acre, or 1 kilogram per acre with urea and foliar fertilizer plus water spray, every 10 days, according to the recovery of wheat seedlings to determine the number of spraying.
Insect pests are drought-prone in spring, suitable for wheat spiders to reproduce and endanger. The wheat spider sucked the wheat leaf juice with a sucking mouthpart, resulting in a needle-like white spot on the wheat leaf. In severe cases, the entire leaf became gray, gradually yellowing, withering and death. When the amount of insects in the field is high, avermectin, bufalin, and omethomethine can be used to control the spraying of pesticides. When applying pesticides, pay attention to the amount of sufficient water to make the liquid enter the roots of the wheat seedlings so as to improve the control effect.
Diseases The main disease of wheat during the period of turning green is sheath blight, which is mainly caused by invading plants. At the beginning of the disease, yellow dots were produced on the leaf sheath of the plant base, and later developed into yellow-brown fusiform or mottled lesions. Severely diseased stems are rotted at the base, young seedlings are not smoked, and severely yellowed. Can be used Jinggangmycin, hexaconazole, tebuconazole and other drugs, add enough water to the base of coarse seed spray prevention, severe disease field can be controlled once in 7 days.
After freeze-damaged wheat turns green, especially after jointing, it is very sensitive to low temperature, and it is prone to frost damage in case of severe temperature-reducing weather. The leaves of frozen wheat seedlings are dark green in color and resemble boiled water, and then gradually wither. The growth cones are initially opaque, and later the cells disintegrate and gradually wither and stop growing. To prevent cold damage to wheat, we must use varieties with strong cold resistance, timely sowing, reasonable close planting, cultivating strong seedlings for overwintering, and enhancing plant resistance to stress. In early March, the promotion will be the priority, and the temperature will be increased in time. After the occurrence of frost damage, nitrogen fertilizers, etc., may be appropriately added according to the degree of frost, so as to promote the recovery of the wheat seedlings.
In areas with low waterlogging or drought, or in poorly-drained fields, it is prone to waterlogging in continuous rainy weather. The growth of wheat roots is affected, resulting in thin and weak seedlings and yellow leaves. When it was dry, the whole yellow wheat field was relatively uniform and the wheat was short. We should open the "three channels" inside and outside the field, meet the continuous rainfall and drainage in time, and timely irrigation in case of drought, and apply a small amount of nitrogenous fertilizer in the rain.
Nitrogen deficiency showed field yellowing of wheat seedlings, thin seedling growth and poor tillering. Can apply urea 5 to 10 kilograms per acre, or 1 kilogram per acre with urea and foliar fertilizer plus water spray, every 10 days, according to the recovery of wheat seedlings to determine the number of spraying.
Insect pests are drought-prone in spring, suitable for wheat spiders to reproduce and endanger. The wheat spider sucked the wheat leaf juice with a sucking mouthpart, resulting in a needle-like white spot on the wheat leaf. In severe cases, the entire leaf became gray, gradually yellowing, withering and death. When the amount of insects in the field is high, avermectin, bufalin, and omethomethine can be used to control the spraying of pesticides. When applying pesticides, pay attention to the amount of sufficient water to make the liquid enter the roots of the wheat seedlings so as to improve the control effect.
Diseases The main disease of wheat during the period of turning green is sheath blight, which is mainly caused by invading plants. At the beginning of the disease, yellow dots were produced on the leaf sheath of the plant base, and later developed into yellow-brown fusiform or mottled lesions. Severely diseased stems are rotted at the base, young seedlings are not smoked, and severely yellowed. Can be used Jinggangmycin, hexaconazole, tebuconazole and other drugs, add enough water to the base of coarse seed spray prevention, severe disease field can be controlled once in 7 days.
After freeze-damaged wheat turns green, especially after jointing, it is very sensitive to low temperature, and it is prone to frost damage in case of severe temperature-reducing weather. The leaves of frozen wheat seedlings are dark green in color and resemble boiled water, and then gradually wither. The growth cones are initially opaque, and later the cells disintegrate and gradually wither and stop growing. To prevent cold damage to wheat, we must use varieties with strong cold resistance, timely sowing, reasonable close planting, cultivating strong seedlings for overwintering, and enhancing plant resistance to stress. In early March, the promotion will be the priority, and the temperature will be increased in time. After the occurrence of frost damage, nitrogen fertilizers, etc., may be appropriately added according to the degree of frost, so as to promote the recovery of the wheat seedlings.
In areas with low waterlogging or drought, or in poorly-drained fields, it is prone to waterlogging in continuous rainy weather. The growth of wheat roots is affected, resulting in thin and weak seedlings and yellow leaves. When it was dry, the whole yellow wheat field was relatively uniform and the wheat was short. We should open the "three channels" inside and outside the field, meet the continuous rainfall and drainage in time, and timely irrigation in case of drought, and apply a small amount of nitrogenous fertilizer in the rain.