Technical Guidance on Promoting Early Maturity and Preventing Early Frost in Northeast Corn, issued by the Ministry of Agriculture in 2014

Website news  During this year's corn sowing and emergence period in Northeast China, climatic conditions were generally favorable, with good matching of light, water and temperature, and corn growth was overall better than the usual level, but in some areas low temperatures and spring waterlogging delayed the sowing period of corn, and the growth process was postponed. At present, Northeast corn is at the tasseling and silking stage, and is successively entering the key period of booting and grain filling and yield formation. In view of the possibility this year, under the influence of an El Nino event, of autumn drought and earlier-than-usual first frost in Northeast China, the Ministry of Agriculture organized experts to formulate technical guidance on promoting early maturity and preventing early frost in Northeast corn, so as to effectively strengthen field management, ensure safe maturity of corn, and make every effort to achieve a bumper autumn grain harvest.

First, prevent drought and drain waterlogging to promote growth. The period from 10 days before tasseling to 20 days after tasseling is the period in the life of corn with the greatest water demand, the largest water consumption, and the greatest sensitivity to water. According to soil moisture and seedling growth, timely and appropriately irrigate with tasseling and grain-filling water to effectively prevent “autumn drought” and promote large ears and full grains. In August, Northeast China is still in the flood season, and low-lying waterlogging-prone plots should promptly be drained and depressions opened to release water and reduce soil moisture, avoiding severe yield reduction caused by lodging due to waterlogging damage.

Second, apply fertilizer rationally to increase grain number and grain weight. According to soil fertility, seedling growth and earlier fertilization, apply topdressing in a timely manner. For fields with sufficient basal fertilizer and intertillage topdressing and good growth, no further topdressing may be needed; for fields with insufficient fertility, at the large trumpet stage, combined with irrigation or effective rainfall, open furrows beside the rows and apply fertilizer deeply, applying 25-30 kg of urea per mu, or use 150-200 g of potassium dihydrogen phosphate per mu mixed with 30 kg of water for foliar spraying; high-yield fields may appropriately increase the amount, to accelerate the growth process, prevent premature leaf senescence, enhance root vitality, and increase grain number and grain weight.

Third, use pesticides scientifically to prevent disease and control insects. In view of the possible heavier occurrence this year in Northeast China of corn borer, armyworm, aphids, as well as northern leaf blight, southern leaf blight, brown spot and other diseases and insect pests, monitoring and early warning should be strengthened, pesticides should be selected scientifically, green prevention and control technologies such as using Trichogramma to control corn borer and black light lamps or sex attractants for trapping and killing should be promoted, and multiple measures such as high-clearance self-propelled mechanical spraying and aerial control should be comprehensively used to carry out emergency control and unified prevention and control at the appropriate time. For plants with disease, promptly remove the lower diseased leaves and take them out of the field for centralized burning, to reduce sources of pathogen infection.

⟦NL> Fourth, promote early maturity and prevent frost damage. Adopt measures such as loosening autumn ridges, removing large weeds, cutting off empty stalks and diseased plants, removing lower leaves, removing ineffective ears, stripping and drying on standing stalks, and spraying potassium dihydrogen phosphate to improve field ventilation and light transmission conditions, reduce nutrient consumption, and accelerate grain filling. Prevent removing the middle and upper stems and leaves of corn too early, and promote transfer of nutrients to the ear. For late-maturing varieties and low-lying plots, place chaff, corn straw, weeds, etc. at the upper windward side and ignite them for fumigation to increase the local environmental temperature. Where conditions permit, spray plant growth regulators such as mepiquat chloride and chlormequat to enhance stress resistance and cold resistance.

Fifth, harvest late at the appropriate time to dehydrate and improve quality. Before the arrival of early frost, delay corn harvest as much as possible, make full use of corn after-ripening, and extend the effective grain-filling time; it is best to carry out mechanical harvest when the bracts are dry, the black layer appears, and the milk line of the grains disappears. Spray corn dehydrating agent 10 days before harvest, at 60-100 ml per mu, mixed with 15-20 kg of water and sprayed on the three leaves at the ear, to accelerate grain dehydration, reduce moisture content, and improve yield and quality. For plants that remain green and mature late, harvest in time for silage as feed. After corn harvest, stack by methods such as arranging in rows, putting into cribs, placing ears on house roofs, and selecting and classifying ears, to accelerate dehydration and prevent grain mildew.

(Ministry of Agriculture Corn Expert Guidance Group, National Agricultural Technology Extension Service Center)