Ministry of Agriculture Issues Technical Guidance on Combating Summer Drought and Protecting Autumn Grain in Huang-Huai-Hai Summer Maize
Maize Expert Steering Group of the Ministry of Agriculture
(July 30, 2014)
Since June, precipitation in most of the Huang-Huai-Hai region has been below normal, with sustained high temperatures in July, and drought conditions developing rapidly in some areas. At present, summer maize in the Huang-Huai-Hai region is at the large trumpet stage, with some entering the tasseling and silking stage, which is the period of greatest water demand and greatest sensitivity to water shortage. In response to the adverse effects of the continuously developing drought on the growth and development of summer maize, the Ministry of Agriculture organized experts to formulate technical guidance on combating summer drought and protecting autumn grain in Huang-Huai-Hai summer maize, proposing to focus on “science-based drought resistance, classified guidance, simultaneous fertilizer and water application, and disease and pest control”, earnestly strengthening field management, and minimizing disaster losses to the greatest extent possible.
(1) Open up drought-resistant water sources extensively, and irrigate as much as possible. At present, maize in the Huang-Huai-Hai region is in the critical period of female and male ear development, and maize plants have an increased demand for water. Drought will reduce the number of viable silks and kernels, and will also make tasseling difficult, forming “neck-stuck drought”. It is necessary to overcome the mentality of relying on heaven and waiting for rain, make full use of all drought-resistant water sources, dig ditches and channels, drill wells and lift water, accelerate irrigation progress, expand the irrigated area, and strive to irrigate every ridge and every mu possible. At the same time, according to actual conditions, adopt water-saving technologies such as sprinkler irrigation, furrow irrigation, sectional irrigation, small-border irrigation, pipeline water conveyance, and alternate furrow irrigation to improve water use efficiency and reduce the adverse effects of high temperature and drought on maize.
(2) Apply measures according to land, seedlings, and soil moisture, and do a good job in classified management. In the allocation of water resources, limited water sources should be allocated mainly to medium- and high-yield fields with good moisture conservation effects and large yield-increasing potential. For plots with different seedling conditions, irrigate maize that has grown to the large trumpet stage first, and then irrigate maize that has already tasseled and shed pollen or is around the jointing stage. In water-scarce areas of hills and slopes, moisture can be conserved by shallow hoeing to reduce surface water evaporation and prolong the drought tolerance time of maize. For maize that has already tasseled and shed pollen, adopt manual supplementary pollination to reduce the impact of high temperature on seed-setting rate. For areas that have not yet formed agricultural drought, prepare all drought-resistance preparations early, and for plots with severe damage and total crop failure, replant and reseed in a timely manner to make up for disaster losses.
⟦NL> (3) Apply fertilizer and water together to promote growth and development. For irrigated plots, where conditions permit, shallow intertillage should be carried out after irrigation to cut off the capillaries in the surface soil layer and reduce field water evaporation. In places where precipitation has recently occurred, apply ear fertilizer in a timely manner, applying 15-20 kg of urea per mu to promote rapid maize growth. For plots where the drought has not been relieved, spray foliar fertilizer in a timely manner, with potassium dihydrogen phosphate at 800-1000 times dilution or Handilong at 500-1000 times dilution, to lower temperature and increase humidity and improve the drought resistance of plants. For plots with delayed growth period and small or weak seedlings, increase urea application to accelerate the growth process.
(4) Prevent diseases and control insects to reduce damage and losses. Wetness breeds disease, drought breeds insects. Sustained high temperature and drought can easily cause relatively severe outbreaks of armyworms, aphids, corn borers, and others. According to pest and disease information released by plant protection departments, carry out emergency control in a timely manner. Scientifically grasp the timing and dosage of pesticide application; apply pesticides in the morning and evening, appropriately increase the number of applications, and reduce the pesticide concentration to avoid phytotoxicity. Choose pyrethroid, organophosphorus, or insect growth regulator insecticides for spraying, or use phoxim, chlorpyrifos, or Bt granules applied into the maize trumpet to control pests. Where conditions permit, adopt mechanical control and aerial control operations to improve control efficiency. Areas with sufficient rainfall and good soil moisture should pay attention to controlling diseases such as dwarf mosaic disease, rough dwarf disease, and leaf blight.