Guidance on the late management of winter wheat in Wanrong County from 2023 to 2024

At present, winter wheat in our county is in the flowering and filling period, which is a critical period for wheat yield formation and fertilizer and water management. According to the survey, the soil moisture in the county is generally suitable, the overall growth of wheat is good, and the proportion of first- and second-class wheat fields has increased compared with before winter. In the field management of winter wheat in the later stage, the number of grains and the weight of the grain should be the goal, the focus should be on disaster prevention and loss reduction, the water and fertilizer should be reasonably regulated, and the harvest should be carried out in a timely manner to ensure a bumper harvest.

1. Rational water fertilizer management

The core of the later management of wheat is to maintain the normal physiological function of the root system, prolong the green leaf stage as much as possible, ensure the supply of photosynthetic products to the grains, increase the number of grains per spike, increase the 1000-grain weight, and carry out the regulation and management of water and fertilizer scientifically and appropriately.

(1) Watering appropriately due to moisture. When wheat enters the flowering and filling stage, the lack of soil moisture will lead to the degradation and shrinkage of florets and grains, and reduce the number of grains and grain weight per panicle. When the relative moisture content of the soil is less than 60%, it should be watered in time. Attention should be paid to controlling the amount of watering, and the amount of watering per mu of flood irrigation should not exceed 70 m3, the amount of watering per mu of sprinkler irrigation should not exceed 40 m3, and the amount of watering per mu of drip irrigation should not exceed 30 m3. Do not drought and water, fertilizer fields are watered less, to prevent greedy green and late maturity; Do not water in rainy days, and do not water in the first half of the month before maturity to prevent lodging.

(2) Foliar spraying. Foliar spraying during this period can make up for the lack of root absorption capacity, effectively increase the fertility supply of plants, enhance wheat stress resistance, prolong leaf functional period, accelerate grain filling speed, increase the number of grains per spike, stabilize 1000-grain weight, and improve yield and quality. Generally, 200 grams of potassium dihydrogen phosphate per mu are sprayed with 40~50 kg of water. For strong gluten wheat, fertilized yellow wheat fields, and affected wheat fields, it can be sprayed with an appropriate amount of urea mixture, 1~2 kg of urea and 100 grams of potassium dihydrogen phosphate per mu, 40~50 kg of water, foliar spraying 2~3 times, and the spraying interval is about 10 days. Foliar fertilizer spraying can also be carried out in combination with "one spray and three preventions", and at the same time, it is sprayed with insecticides, fungicides and plant growth regulators, which can prevent diseases and insects, prevent premature aging, and prevent dry and hot air.

2. Prevent and respond to meteorological disasters in a timely manner

In the late stage of wheat growth, there is still the possibility of drought and low temperature and cold injury, and disasters such as dry and hot wind, hail, strong wind, bad rain, diseases, insects and weeds also occur from time to time, which have an adverse impact on wheat production. Therefore, it is necessary to give prominence to the work of disaster prevention and loss reduction to ensure that the output is in hand.

(1) Drought. According to the forecast of the county meteorological department, the temperature will be high in May, the precipitation will be low, the overall moisture will decline, and there may be local drought. If there are watering conditions, when the soil moisture becomes worse, timely and appropriate watering to replenish the moisture. If there is no watering condition, a high-clearance self-propelled sprayer and a drone can be used for foliar spraying or waterwheel pulling water, and the "little white dragon" can replenish water.

(2) Low temperature chilling injury. In the first half of May, there is still the possibility of low temperature chilling injury, if the minimum temperature is lower than 5~6 °C, the duration is more than 8 hours, wheat may be damaged. Therefore, it is necessary to pay close attention to the weather forecast, and take measures such as irrigation, spraying anti-frost or spraying smoke before the arrival of low temperature to prevent and reduce the occurrence of low temperature and cold damage. Once it occurs, it should be watered or foliar sprayed with potassium dihydrogen phosphate and brassinolide in time to promote restorative growth.

(3) Dry and hot air. Wheat is often damaged by hot and dry wind, resulting in early maturity or wilt, and the grain weight is seriously reduced. Therefore, in areas where hot and dry winds are common, active preventive measures can be taken. The first is to pour the grouting water at the right time. Generally, watering during the milk maturity period, wax maturity period, and before the perennial dry and hot wind period can effectively reduce the microclimate temperature of wheat field, increase humidity, reduce the intensity of plant transpiration water consumption, and effectively reduce the harm. The second is to spray 2~3 times with 0.2~0.4% potassium dihydrogen phosphate solution at the stage from heading to grain filling, mix a small amount of boron fertilizer, increase the content of phosphorus, potassium and boron in the plant, and improve the stress resistance and filling rate of wheat. Third, 300 grams of vinegar or 50 grams of acetic acid can be added to 40~50 kg of water per mu and foliar spraying twice (with an interval of 5~7 days) to enhance the ability of wheat to resist dry and hot winds.

(4) Hail. Hail is a local occasional disaster in the late stage of wheat production, and once it occurs, it causes large losses to wheat. After hail, the leaves fall off, the ground coverage is small, the temperature of the wheat field is high, and the soil evaporation is large, so the appropriate amount of fast-acting fertilizer should be applied in time in combination with watering, and attention should be paid to foliar top dressing, and the disease prevention and insect control work should be done in time to promote the recovery of plant growth as soon as possible. Due to the strong adjustment ability of wheat population, there will be regenerated wheat after hailstorm, but the maturity period is late, so attention should be paid to the appropriate application of phosphorus fertilizer to promote early maturity.

(5) Gale. If there is windy weather during the grain filling period, it is necessary to stop field irrigation immediately to prevent the risk of root lodging and stem lodging due to excessive soil and plant water content. If the wheat lodging is in the later stage, it is necessary to avoid manual righting to prevent the expansion of the lodging area caused by mechanical disturbance. After lodging, the wheat field can be sprayed with potassium dihydrogen phosphate on the foliar surface of the UAV to enhance its stress resistance, and at the same time, it is necessary to pay attention to prevent the spread of diseases such as rust, powdery mildew and scab in the lodging wheat field.

(6) Bad rain. In the later stage of wheat growth, it encountered "bad rain", which affected the wheat harvest and led to ear germination, resulting in a serious decline in wheat yield and quality. In the event of "bad rain" weather, it is necessary to dispatch suitable drainage machinery, clean the ditches in time, remove the stagnant water in the field, promote the growth and recovery of wheat, and facilitate machine harvesting. It is necessary to mobilize crawler harvesters to participate in the harvest, and the first time can be harvested. For wheat with signs of germination and germination, organize mechanical harvesting immediately after the rain and sunshine; For lodging wheat fields, it is necessary to lower the header, reduce the vehicle speed, and reverse harvest to reduce losses. It is necessary to do a good job of drying and drying wheat to prevent direct accumulation and mildew.

3. Actively prevent and control diseases, insects and weeds

The plant protection department should increase the monitoring and census of pests and diseases, organize and carry out prevention and control in a timely manner on the standard fields, clarify the main control objects, take into account the secondary pests and diseases, use drugs scientifically, and comprehensively control them, and pay attention to the protection and use of natural enemies to give full play to the natural control role of natural enemies.

(1) Diseases. The heading and flowering stage focuses on the prevention and control of scab, rust, powdery mildew, etc. Highlight the prevention of scab, adhere to the "see the flowers, bloom and then fight", curb the epidemic of the disease, once the heading and flowering period in case of rainy weather immediately spray prevention; Cyanoxystrobin, prothioconazole, fluazole hydroxylamine, tebuconazole, propazole tebuconazole, cyanoene tebuconazole and other agents can be used. stripe rust adheres to the principle of "finding a little and preventing a piece", and controls the disease center in a timely manner; When the average diseased leaf rate in the field reaches 0.5%-1%, organize and carry out large-scale emergency prevention and control, and achieve full coverage of prevention and control in similar areas. Tebuconazole, fluconazole, propiconazole, propazole tebuconazole and other agents can be used. For powdery mildew and leaf rust, it can be combined with wheat "one spray and three preventions", and the scientific mixing of insecticides and fungicides can be implemented for comprehensive control.

(2) Pests. During the grain filling period, the focus is on the prevention and control of wheat ear aphid, and comprehensive medication is advocated to achieve multiple effects in one spray. When the amount of 100 ears of aphids in the field reaches more than 800 and the benefit-harm ratio (natural enemy: aphid) is less than 1:150, acetamiprid, imidacloprid, anti-aphid, pymetrozine, cyhalothrin and other agents can be used for spray control. In areas where conditions permit, it is advisable to release natural enemy insects such as aphids and cocooned bees for biological control.

(3) Grass damage. In wheat fields with heavy grass damage in the late stage of wheat growth, grass seeds tend to mature earlier than wheat and have a higher reproductive coefficient, especially grasses. It is necessary to manually pull out the weeds before they set fruit, reduce the amount of grass seeds left in the field, and prevent the spread of disasters. At the same time, it is necessary to pay attention to the prevention of weeds on the ground to prevent grass seeds from being brought into the field due to watering and tillage.

Fourth, timely harvester harvest loss

Harvesting at different maturity stages of wheat has a great impact on yield, and the end of wax maturity is the best time for wheat harvesting. It is necessary to pay close attention to weather changes, and at the end of wax maturity, when all the wheat plants are yellow, and it is not easy to pinch the wheat grains with fingernails, it is the most suitable harvest period for wheat. On the day of harvest, try to avoid the hot noon, harvest in the morning and afternoon, to prevent the high temperature at noon from causing the grain to collapse and cause losses. It is necessary to implement the measures to reduce the loss of machine harvesting, and carry out a comprehensive inspection and maintenance of the combine harvester before harvest to ensure that the machine can work normally throughout the harvest period. When the operation turns, the harvest should be stopped, and the harvest should not be turned while cutting, so as to prevent the harvester and walking wheel from overwhelming the uncut wheat and causing missed cutting. When the wheat population is dense, the yield is high, and the humidity is high in the morning and evening and after the rain, the operation speed should be appropriately reduced to prevent missed cutting. The stubble height is generally 5~15 cm, and the speed of the wheel is generally 1.1~1.2 times the forward speed of the combine harvester.