What to do if the leaves of rape turn purple in winter? A few tricks to make the rape leaves green again
Explanation and rationale for the problem.
In winter, when temperatures are low and soil moisture is low, it is common for leaves to turn purple. The first thing to notice is the change in the paddle blades and find the problem. The factors that cause the purple color of leaves include nutrient deficiency, trace element deficiency, insect pests, drought and water shortage. After fertilizer deficiency, the cause of leaf color turning red is the lack of nitrogen and phosphorus, and some trace elements, such as sulfur and boron, will also make the leaves red. Most of the damage from insects comes from aphids, while drought and water scarcity are caused by a lack of soil moisture.
Insufficient fertilization is an important factor causing rapeseed leaves to turn red. When the plant lacks nitrogen, the edges of the leaves turn red and the middle turns yellow. When the leaves are yellow-red, the plant stops growing and the new leaves become very slow. Phosphorus deficiency also causes the leaves to turn red, and the edges and petioles of the leaves will turn purplish-red, and the back of the leaves will also turn purple. Under such conditions, the whole plant will appear thin and thin, and the newly grown leaves will become smaller and smaller.
When there is a lack of trace elements, it can also cause the rape leaves to turn red. In case of sulfur deficiency, the young leaves turn yellow, and then slowly grow lilac spots, and the edges will also be destroyed and warped. The dorsal surface and veins of the leaves are also purple. When boron is deficient, the leaves become thicker, brittle, purple, wrinkled, and even the entire leaf turns yellow and dies.
In addition, pests can also cause rape leaves to turn red. Aphids are a very common insect pest that generally inhabits the underside of leaves and is difficult to spot unless they are turned over. When attacked by aphids, the leaves of the entire plant will become crumpled, yellow, and finally yellow.
In addition, the lack of water is also a factor that causes the color of rape leaves to turn red. In the northern part of China, due to low temperatures and scarce rainfall in winter, there is a lack of soil moisture. If there is a lack of moisture, the leaves will turn red, and they will grow sluggishly, making them look short.
Countermeasure. In order to effectively deal with the problem of leaf reddening, a feasible method was proposed. First of all, in order to solve the problem caused by insufficient fertilizer, nitrogen fertilizers such as urea and ammonium bicarbonate can be applied, and 15 kg of urea and 35 kg of ammonium bicarbonate can be applied to one acre, and they can be washed and sprinkled in the ground. In addition, superphosphate can also be used as fertilizer, 35 kg of superphosphate per unit area is applied, it is sprinkled in a shallow ditch, and then covered with soil. If the sulfur is insufficient, you can sprinkle 2 kg of sulfur powder on one acre of land, or mix 50 kg of gypsum powder. In the case of boron deficiency, 02% borax solution at 7 days interval for a total of 3 times.
In view of the leaf spot phenomenon caused by pests, corresponding control countermeasures were proposed. First of all, it is necessary to choose appropriate pesticides to spray to control the harm of aphids; It is generally used to control wheat aphids.
If the leaves turn red due to lack of moisture, water the leaves at the right time. In order to keep the soil moist, the method of diversion canal irrigation can be used. After irrigation, fertilizer should be applied in time to promote its green turn and return to its normal growth state.
Brief summary. In northern China, due to factors such as lack of fertilizer, lack of trace elements, insect pests and drought, it is a common phenomenon for leaves to turn red. And put forward corresponding countermeasures. For the problem caused by insufficient soil nutrients, an appropriate amount of n and p can be added to the soil. Deficiencies in trace elements can be supplemented with sulfur and boron. Choose appropriate pesticide spraying to control pests. For drought and water problems, timely irrigation and fertilizer are required to accelerate the greening.
In short, leaf redness is common in winter, but only by taking effective control methods in time can we effectively avoid leaf redness and ensure its healthy growth. Therefore, the majority of farmers should pay close attention to the growth of leaves in the sowing process, and should take immediate measures to ensure the high yield and high quality of rapeseed once there is a problem.