Tremendous rains in Ontario this year, with more on the way, have resulted in “wet feet” for some soybean fields. When wet conditions persist, the soybean crop will start to struggle.
To explain the science behind wet feet, Dr. Dave Hooker, field crop agronomist and associate professor at University of Guelph, joins Bernard Tobin for this Soybean School episode.
“The roots need oxygen to respire, and respiration is needed to produce that energy that makes the plant grow, makes the root grow,” says Hooker. “When those air-filled spaces are taken up in the soil we called it air-filled porosity, because when that is very low because of too much water, the plant can’t get enough oxygen to complete that respiration process.”
So how much water is too much?
Hooker says it depends on the soil type, structure, or crop rotation or history. About 15 per cent of soil pores need to be filled with air, if water fills those pore spaces for too long, a couple days for example, that’s when plants will undergo some stress, which can also be exacerbated by warmer temperatures.
For soybeans, nitrogen fixation will also halt, because to benefit the plant, the roots need oxygen to bring that nitrogen up through the plant. Right off the bat, roots will senesce and die off, adds Hooker.
Check out the full video of Hooker and Tobin in the field at the Ridgetown Campus below: