Diagnosis and skillful treatment of red and yellow seedlings in rape seedling stage

Two kinds of abnormal seedlings of red leaves or yellow leaves often appear in rape seedling stage. Red and yellow seedlings should be treated and treated in order to transform in time. Dry red leaves: rape seedling stage, if there is no rain for a long time, or lack of soil moisture, rape grows slowly due to lack of water, the plant is short, and the leaf color is light red. To solve this problem, furrow irrigation should be carried out in time to resist drought, combined with the application of pre-winter fertilizer, so as to promote the transformation of rape to normal growth. Waterlogging damage to red leaves: too much Rain Water before winter, poor drainage caused by soil waterlogging, poor absorption function and the formation of stiff seedlings, the leaf color was dark red. For red leaves damaged by waterlogging, three ditches should be opened with high standards, and the ditches should be cleared in time to eliminate waterlogging, reduce the groundwater level and eliminate waterlogging damage. At the same time, it is necessary to plough and loosen the soil in time, raise the ground temperature, strengthen the roots and promote growth. Pest red leaves: rape leaves become red, atrophied and stiff when the aphids are seriously harmed at the seedling stage. For the redness of leaves caused by aphids, great heroes, lice aphids and Yichuanjing should be selected in time to promote the recovery of rape growth. Freeze-damaged red leaves: if the weather changes suddenly at the seedling stage, the leaves will turn red due to a sharp drop in temperature. To solve this problem, it is necessary to combine ploughing and cultivating soil with 50 kilograms of wood ash per mu, or spraying 0.3% potassium dihydrogen phosphate solution on leaves, which can reduce the freezing injury. Lack of fertilizer red leaves: rape lack of fertilizer, will show different symptoms of red leaves. For example, phosphorus deficiency is purplish red, potassium deficiency is brownish red, boron deficiency is purplish red and the leaf margin is inverted. For red leaf seedlings caused by phosphorus deficiency or potassium deficiency, appropriate amount of phosphorus and potassium fertilizer can be applied, or 0.2%-0.3% potassium dihydrogen phosphate solution can be sprayed on the leaves. For red leaf seedlings caused by boron deficiency, 0.2% borax solution can be sprayed twice, or 500g / mu of borax combined with rehydration roots. Lack of fertilizer yellow leaves: lack of nitrogen in the seedling stage, the plant is short, the leaf color is obviously faded green to yellow, and the old leaf is yellowish red. The seedlings were zinc deficient, the plants were short, and the new leaves were yellowish white. Rapeseed seedlings lack of sulfur, the plant is light green, the leaves fade green and yellow, and the leaves are few and small. For yellow seedlings with nitrogen deficiency, an appropriate amount of available nitrogen fertilizer can be applied. For yellow leaf seedlings caused by zinc deficiency, 0.1%-0.2% zinc sulfate solution can be sprayed twice in time. For yellow leaf seedlings caused by sulfur deficiency, 10 kg gypsum powder per mu can be applied in combination with ploughing. Disease yellow leaves: rape seedlings infected with virus disease, leaves curled, wrinkled, green uneven and yellowing. The yellow and green markings were formed in Brassica campestris. After the disease of Brassica napus, yellow-brown spots appeared in the leaves. If yellow leaves occur due to viral disease, the central disease plant should be removed in time to reduce the source of the disease. At the same time, the mixture of virus A, Yuanjing (or great hero, Sijihong, etc.) and 500 times edible vinegar can be used to control aphids and control diseases. Acid damage to yellow leaves: planting rape in acidic soil will produce acid damage and make the leaves yellow. This kind of yellow leaves are generally not withered, but they fall off easily. In this regard, 100 kg of plant ash or 50 kg of lime can be applied per mu to reduce soil pH and eliminate acid damage.