Technical guidance on promoting early ripening and protecting Autumn Grain by Maize in Northeast China

During the sowing period of corn in Northeast China this year, it encountered unfavorable weather such as drought and cold in late spring, and the sowing time in most areas was 5-7 days later than usual. Since July, most areas have experienced persistent drought, and the precipitation is generally less than that of normal years. The overall silking period of maize is about 5 days later than that of normal years, and the overall growth process has been delayed. At present, corn in Northeast China is in the period of grain filling. Taking into account the impact of El Nino this year, the northeast region may encounter autumn drought and early frost in advance, the Ministry of Agriculture organized experts to consult, formulate technical guidance for corn to promote early maturity and protect autumn grain in Northeast China, and earnestly strengthen field management to ensure that the particles are returned to the warehouse.

The first is to fight against autumn drought according to local conditions. Pay close attention to weather changes, according to the degree of drought in various places, guide farmers to scientifically save water and fight drought. Drip irrigation, sprinkler irrigation, micro-spraying, Xiaobailong and other high-efficiency water-saving irrigation measures can be adopted in areas with better conditions, while in areas with relatively poor conditions, water-saving irrigation methods such as wrong-time ridge irrigation and alternate ridge irrigation can be adopted to effectively reduce water consumption and cost, so that they should be fully watered, and strive to minimize the impact of drought.

The second is to control diseases and insect pests as a whole. In the year of El Ni ñ o, uncertain extreme weather is easy to cause diseases, insect pests, premature senility and other disasters. It is necessary to do a good job in dynamic monitoring, disaster forecast and early warning of diseases and insect pests in the late growth stage of corn, and reserve medicine and equipment and other related materials. We should adopt the combination of chemical and biological control, carry out unified control, mass prevention and control, and effectively prevent the outbreak of second-generation armyworm, aphids and red spiders.

The third is to strengthen field management to promote early maturity. For the plots affected by drought and delayed development, combined with irrigation, timely and appropriate topdressing of available nitrogen fertilizer to promote grain filling, nitrogen fertilizer should be applied deeply or covered with soil after application to prevent fertilizer damage caused by high temperature; in the later growth stage, measures such as releasing autumn ridges and pulling out grass can reduce the competition for water; through cutting open plants, bottom leaves, standing stalks and peeling to dry, improve ventilation and light transmission capacity, reduce disease infection, reduce nutrient consumption, and promote grain filling. Foliar fertilizer spraying or additional application of plant growth regulators were adopted to speed up grain filling maturity.

Fourth, we should take more measures to prevent early frost. Continuous high temperature and drought delay the growth and development of maize, late-maturing varieties and low-lying plots should pay attention to prevent the attack of early frost. Pay close attention to the early warning information of the meteorological department, irrigate in the evening two days before the frost to increase soil moisture and raise the air temperature near the ground; seize the key period of time, place grain husks, straws, weeds, sawdust, etc., wait for below-zero cold air to arrive and ignite fumigation, or set up wind barriers to the north in the field to increase the local environmental temperature and reduce the harm of low temperature frost.

Fifth, timely machine harvest to ensure a bumper harvest. The harvest time of maize was appropriately delayed before the early frost, so as to prolong the effective grain filling time, accelerate ear and grain dehydration, reduce grain water content, and improve maize yield and grain quality. Harvest will be carried out when the bracts are dry, the black layer appears and the grain milk line disappears. According to the variety characteristics and late drying conditions, mechanical rod picking and grain harvesting were popularized, and the straw was crushed and returned to the field at the same time. After receiving the goods, avoid stacking them in large piles, turn them over frequently, and store them on the stack or in the yard to prevent mildew caused by the accumulation of humidity and temperature.