Water Use of Corn

  • Jun 07
    Danielle MacCallum
    Water Use of Corn By Danielle MacCallum on June 7, 2022
    Categories: Ask the expert, Crop Physiology, Grain Corn, Production, Silage Corn, Tips

    Corn crops typically require approximately 500 to 550 mm (19-22 inches) of water per growing season to reach optimum yield potential. Peak water use occurs from mid-July to mid-August when the crop requires about 7mm of water per day. However, the average annual precipitation in Alberta tends to fall short of this level, with a particularly large deficit in the areas that have the adequate CHU levels to support corn production.

    Adequate water is crucial in the development of corn, as soil water depletion levels less than 60% can begin to have negative impacts on yield. Alberta already has in place extensive infrastructure for the irrigation of corn. There are currently 1,684,160 acres of irrigation available in Alberta; the majority of which are designated within irrigation districts and the remainder privately held. These acres are in the southern region of the province, most of which receive adequate CHU levels to support corn production.

    It is important to make sure that water availability is not restricted during peak use times to ensure optimum pollination and yield. During the tasseling and silking stages corn is very sensitive to stress. At that time, high seasonal temperatures combined with low soil moisture availability may reduce yields an average of 5 per cent per day; under more severe temperature-moisture conditions, reductions can run over 10 per cent per day; and under extreme stress corn fertilization might not even occur, resulting in total crop failure from poor pollination, tassel desiccation, and missing kernels (https://www.extension.purdue.edu/extmedia/nch/nch-18.html). 

    (Alberta Irrigation Management Field Book)

    This degree of drought stress is very extreme and only occurs when the plants are not able to recover overnight. If your corn has rolled leaves one day but they have unrolled the next morning, then you are not experiencing the amount of drought stress that would incur the yield loss percentages listed above. Leaf rolling conserves water by decreasing the surface area of the leaf exposed to sunlight and reducing transpiration as well as photosynthesis.

    Leaf rolling.