When doing field technical services to farmers, it was found that cotton fields in many plots had premature aging in light or heavy areas. Through communication, many farmers either did not notice the premature aging of cotton on their farms, or did not pay attention to the premature aging of cotton. Although some farmers discovered the premature aging of cotton, they did not know how to prevent and remedy it, and even some farmers made mistakes. The premature aging of cotton is regarded as premature cotton. 1. What are the symptoms of premature cotton aging? Even the best cotton varieties are prone to premature aging and related problems if they do not have scientific cultivation and management techniques. There are many reasons for the occurrence of premature aging, which have varying degrees of impact on the yield and quality of cotton. To capture the high yield and high quality of cotton, the most important thing in the middle and late management is to prevent premature aging. The premature senescence of cotton mostly occurs from late August to early September. After the cotton plant grows into the flower and boll stage, because the absorption capacity of the root system is weakened, it cannot supply more water and nutrients to the upper part of the ground. Especially when the cotton enters the full-flowering stage and the growth center turns to the reproductive organs such as the bud and the bell, the reproductive organs such as the bud and bell have Competing with vegetative organs for organic nutrients produced by leaves further inhibits vegetative growth. At this time, the cotton plant has set up a certain number of bolls in the middle and lower part, and the upper cotton plant can have a red stem ratio of more than 90%, the growth point becomes sharp, the flower position moves up, the top flower bud is lurking, and no new fruit branches are extended. , The number of fruit branches is 2 to 4 layers less than normal; the root system is exhausted, the roots are shallow, and the roots are few, and the ability to absorb fertilizer and water is greatly reduced; the leaves are thin and yellow, the buds are small, the flowers are weak, the peach is small, the buds and bells fall off more, the lint is low, and the quality changes Inferior, the maturity of the seeds is poor. 2. There are many reasons for premature cotton aging The root cause of premature aging of cotton is the inadequate nutrition of the cotton plant during the fluffing period, which causes the cotton plant to age and die prematurely. The common causes of premature senescence of cotton plants are as follows. Fertilization is unreasonable. August is the period when a large number of cotton blooms and bolls, which is a key period for cotton to reach high yields, and it is also the peak period for cotton to require fertilizer. If flower-bell fertilizer and peach fertilizer are insufficient or not applied at all, the contradiction between vegetative growth and reproductive growth will be aggravated, the upper fruit branches will not stretch, the cotton leaves will yellow quickly, and the stamina will be obviously insufficient. Especially in the early-growing cotton fields, because the peaches sit earlier and the load is heavier, they are more prone to premature aging. In the boll period of cotton, insufficient potassium fertilizer is very harmful. The lack of potassium in the cotton field will reduce the utilization of nitrogen fertilizer by the cotton plant and reduce the boll weight; it will also reduce the resistance of the cotton plant to fusarium wilt; in particular, the leaves will scorch and fall off earlier. Severe potassium deficiency can cause red leaf stem blight in cotton fields, causing a large number of leaves to fall off and premature senescence. This disease is easy to occur even when nitrogen and phosphorus fertilizers are sufficient. It should be particularly reminded that the genetically modified hybrid insect-resistant cotton that is now commonly planted is very sensitive to potassium fertilizer. Compared with conventional cotton, the amount of potassium fertilizer needs to be more than doubled. In addition, trace elements such as boron, calcium and magnesium can promote the growth and development of cotton roots and improve the absorption function of the roots. If it is lacking, it will cause poor root development and cause premature aging. The weather is abnormal. Drought or waterlogging in the early stage of Lei Ling will cause serious underdevelopment of the root system and cause irreversible damage to the root system. In the middle and late stages of drought, if there is no irrigation or drought resistance is not timely, it is difficult to absorb and use fertilizers, and nutrients cannot keep up, leading to premature aging. In the middle and late stages of cotton growth, if continuous rainy weather occurs, there will be sudden diseases such as angular leaf spot, black spot, brown spot, blight and other diseases infect the leaves, which will cause premature aging due to impaired leaf function and affect photosynthesis. Pests and diseases. Diseases and insect pests can cause premature aging, especially in cotton fields with serious damages such as Verticillium wilt and red spiders, cotton aphids, cotton bollworms, etc. The vascular bundles for nutrient transport are damaged, the cotton leaves are damaged, the organs that produce and transport nutrients are damaged, and premature aging It goes without saying. other factors. Early sowing of early-maturing varieties will artificially advance the growth period, causing the senescence of the root system to meet the blooming and bolling period, and premature aging; if early sowing encounters cold spring, low temperature, slow root growth and serious diseases, it is easy to lead to nutrient supply in the later period Premature aging occurs if it does not go up; heavy wind and rain can cause serious lodging of cotton plants, damage to the root system, and premature aging. 3. Prevention of premature aging of cotton is more important than cure In recent years, the occurrence of premature aging of cotton is more common, and the occurrence is more early, and the damage is more and more serious, which has a great impact on the yield and quality of cotton. At the same time, because there are many factors that cause premature aging of cotton, and there are many potential factors, so, Preventing premature aging of cotton cannot wait until the occurrence of premature aging and then "make up for it", but should take precautions and prevent them in advance. Strengthening fertilizer and water management in the middle and late stages is an effective measure to control the premature aging of cotton fields. It is suggested that cotton growers should not have enough base fertilizer or less top dressing. At present, cotton plants are showing weak growth, thinning leaves, and light-colored cotton fields. When the cotton is in the blooming period, early measures should be taken to prevent cotton from occurring. Premature aging. Fertilization management. It is necessary to reapply flower bell fertilizer according to the seedling condition, climate and soil strength. If the flower bell fertilizer is insufficient, reapply top-cap fertilizer in time. The best time to apply top fertilizer is after topping the heart, from the end of July to the beginning of August. For the varieties prone to premature senescence with many Fuqian peaches and Futao peaches, topdressing should be applied to fields with heavy sandy soil, low-lying soil and poor soil, and thin stems and branches. Topdressing must be applied before August 15th, and it can be applied in the middle of the big cotton industry. Do not get too close to the roots, so as not to damage the roots and burn the roots and cause premature aging. The occurrence of red leaf stem blight is the main cause of premature senescence of cotton, and the disease is mostly caused by a serious lack of potassium in the soil. When basal fertilizer is applied, 5-10 kg of potassium sulfate or potassium chloride should be added at the seedling stage. . After cotton enters the blooming period, the root vitality weakens and the ability to absorb fertilizer is poor. In the middle and late stages of cotton, timely foliar spraying of urea has quick effect and high fertilizer efficiency, and has obvious effects on preventing premature aging, reducing shedding and increasing boll weight. Drip management. The flowering and boll period is the peak period of water demand for cotton (accounting for 45% to 65% of the total water demand). If the cotton plant grows well in the early stage, the lack of water will cause premature senescence of large trees. If there is continuous heavy rain after drought, Prone to sudden death premature aging. In the hot weather, you should observe frequently. Once the cotton plants are found to be wilting at noon, they should be watered in time to maintain the root system, improve the nutrient delivery of the cotton, and ensure that the fertilizer efficiency is played in time. Do a good job in pest control. The functional period of normal leaves is generally about 8 weeks. However, due to the effects of insect pests such as cotton bollworm, cotton aphid, cotton bug, spider mites and diseases such as fusarium wilt, verticillium wilt, red leaf stem blight and other diseases, the leaves are damaged or fall off. The function of the leaf is improved, and the premature aging is accelerated. Therefore, we must prevent and control pests, reduce diseases, and extend leaf function. Timely control. Adhere to the principle of "small amount and many times, light in front and heavier in front" of methenamine administration. Disclaimer: Some articles on this website are transferred from the Internet. 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