Drought Hits Corn in Northeast China: Ministry of Agriculture Releases 2014 Techniques for Drought Resistance and a Bumper Harvest
According to this website since July, precipitation has been low and temperatures high in central and western Inner Mongolia and western and southern Liaoning, with soil moisture depletion and severe summer drought; corn plants have wilted and leaves have yellowed to varying degrees. The meteorological department predicts that there will be no effective rainfall in the drought-affected areas in the near term, and the drought will continue. “Start of Autumn” has passed, and spring corn in Northeast China is at the tasseling and silking stage, the peak water demand period and the stage most sensitive to water shortage. To effectively respond to the current drought and possible continuous summer-autumn drought, the Ministry of Agriculture organized experts to formulate technical guidance for drought resistance and a bumper harvest of spring corn in drought-affected areas, proposing to focus on “resisting high temperatures, preventing continuous drought, promoting grain filling, and ensuring maturity,” with scientific field management, disaster resistance and loss reduction, and every effort to secure a corn harvest.
(1) Irrigate early to create soil moisture and protect seedlings. Make full use of drought-resistant water sources and water-saving drip irrigation projects, giving priority to ensuring water use for high-yield fields and fields at the critical water shortage stage. According to seedling growth and changes in soil moisture, promptly adopt shallow irrigation with small amounts of water to maintain normal grain filling and seed setting in plants. Where conditions permit, adopt drip irrigation, sprinkler irrigation, furrow irrigation, “Xiaobailong” and other irrigation measures to replenish water in time and expand the effective irrigated area. Where conditions do not permit, use methods such as staggered ridge irrigation and alternate irrigation in every other ridge to reduce water consumption, lower field temperatures, and minimize losses caused by drought.
(2) Topdress fertilizer to promote growth and strengthen stalks to protect ears. In combination with irrigation and watering, promptly topdress ear and grain fertilizer, applying 10-20 kg of urea per mu, placing it deeply to the side in furrows, avoiding surface broadcasting, to promote downward rooting of corn, enhance nutrient and water absorption capacity, and promote strong stalks and large ears. At the late grain-filling stage, use a high-clearance sprayer to apply foliar fertilizer or plant growth regulators, using 0.5-0.7 kg of urea plus 0.2 kg of potassium dihydrogen phosphate per mu, diluted with 50-100 kg of water, to lower temperature and increase humidity, increase moisture in plant ears and leaves, accelerate grain filling and maturity, and increase grain number and grain weight.
(3) Scientific field management to reduce disasters and losses. One to two days after watering, lightly hoe or shallowly plow once to break soil crusting and reduce water evaporation. For fields where drought has delayed development, promptly carry out artificial supplementary pollination to increase the seed-setting rate. At the late growth stage, through measures such as loosening the autumn ridges, pulling large weeds, cutting empty plants, and removing lower leaves, improve ventilation and light penetration, reduce water competition, lessen disease infection, and ensure full grain filling. For spring corn fields with severe yield reduction or total crop failure, promptly replow and plant open-field vegetables or forage crops. For corn fields where grains are difficult to form, carry out silage in a timely manner to make up for yield losses.
(4) Strengthen monitoring and control pests and diseases. Strengthen monitoring and early warning, closely watch the occurrence trends of corn borer, third-generation armyworm, aphids, leaf spot disease and other pests and diseases, and carry out emergency control and unified control at appropriate times. Scientifically select control agents, grasp reasonable timing and dosage, appropriately increase the number of applications, reduce the concentration of the agents used, and improve control effects. For leaf spot diseases, first remove 1-2 diseased lower leaves and destroy them centrally, then spray 50% carbendazim or 70% thiophanate-methyl 500-fold solution, or 75% mancozeb 500-800-fold solution for control. For corn borer, 6-8 days after the peak silking stage of the female ear, spray with 4.5% beta-cypermethrin 1500-2000-fold solution or 2.5% kung fu 1500-2000-fold solution. For armyworm, spray with diflubenzuron or 4.5% beta-cypermethrin 1500-2000-fold solution and other agents for control.
(Ministry of Agriculture Corn Expert Steering Group, National Agricultural Technology Extension Service Center)