Ministry of Agriculture 2014 Technical Guidance on Promoting Early Maturity and Preventing Early Frost in Soybeans in Northeast China

This website news  This year, some areas in Northeast China suffered severe low-temperature spring waterlogging in spring, soybean sowing was significantly delayed compared with normal years, and some areas experienced periodic overcast and rainy weather with little sunshine during the flowering and podding stage, slowing the growth process, and the maturity period may be later than normal. The meteorological department predicts that, affected by the possible moderate-or-stronger El Nino event, the first frost date in Northeast China this year may come earlier. In order to promote normal growth and development of soybeans and ensure safe maturity, the Ministry of Agriculture organized experts to put forward technical guidance for Northeast China on promoting early maturity and preventing early frost in soybeans, focusing on “draining water to reduce waterlogging, foliar fertilizer spraying, and artificial smoking.”

(1) Drain water to reduce waterlogging and promote growth. In August, Northeast China is still in the flood season, with relatively more rainfall. For low-lying areas or plots prone to waterlogging, measures such as mechanical drainage and trench digging should be used to promptly remove accumulated water in the fields and stagnant water in the plow layer. After drainage, promptly straighten and earth up the plants, wash off the silt on the surface, and promote soybeans to return to normal growth as soon as possible.

(2) Spray foliar fertilizer to promote early maturity. Foliar fertilization during the flowering and podding stage can accelerate the soybean growth process and promote normal maturity. Generally, urea plus monopotassium phosphate is sprayed on the leaves, with an amount of 350-700 grams of urea plus 150-300 grams of monopotassium phosphate per mu, and trace fertilizers may be appropriately added according to soil nutrient deficiency conditions. Generally, 25 grams of ammonium molybdate and 100 grams of borax are used per mu, mixed with water and sprayed; the spraying time is preferably after 4 p.m., and spraying may be done 2-3 times during the flowering and podding stage. Farmers with the means may also spray high-concentration foliar fertilizers such as brassinolide and growth regulators such as mepiquat chloride and chlormequat, to effectively supplement nutrients and enhance the plant's stress resistance and cold resistance. At the same time, by pulling out large weeds in the field, increase field ventilation and light penetration, and promote soybean growth and development.

(3) Artificial smoking to prevent early frost. Closely monitor weather change trends. At 2-3 a.m., when the temperature drops to the critical temperature of 1-2 degrees C at which crops suffer damage, adopt the method of artificial smoking to prevent early frost. At the upwind edge of immature soybean plots, place straw, leaves, weeds, etc. and ignite them, letting them smolder slowly, so that the ground is covered with a layer of smoke, raising the near-ground temperature by 1-2 degrees C, changing the local environment, and reducing frost damage. The smoking piles should be dense and evenly distributed, and the smoke should cover the entire field surface as much as possible. In addition, burning chemical substances such as red phosphorus in the field to form a smoke screen also has a frost-prevention effect.

(Soybean Expert Steering Group of the Ministry of Agriculture, National Agricultural Technology Extension Service Center)