Effective irrigation scheduling starts with a good knowledge of farm fields, crops and their water needs.
Sarah Sommerfeld, an irrigation agrologist with Saskatchewan Agriculture at Outlook, says farmers need to know their soil’s texture, its water-holding capacity and spring moisture content and water needs at different plant growth stages.
“Irrigation scheduling starts when the crop goes in the ground,” she said.
Sommerfeld said the goal of irrigation scheduling is to ensure water is available to the plant and is applied according to crop requirements.
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“It’s inhibiting erosion and inhibiting application of water that is not useful,” Sommerfeld said.
In field studies that examined scheduling this past growing season, both Sommerfeld and provincial irrigation agrologist Korvin Olfert of Swift Current were surprised to learn how much water an individual plant needs.
Olfert said mature plants will use eight millimetres of water per day, while young plants use much less. He stressed the need to keep soil at about 50 percent of its holding capacity to avoid plant stress.
“If you don’t have enough water, you’re giving up yield,” Olfert said.
“Without water stress, you can double yield with irrigation.”
The most water is required during flowering and seed set in annuals and following cutting or grazing of forages.
Average water use is specific to each crop and depends on factors such as the date of emergence, daily temperatures and climate.
Sommerfeld, who plans more scheduling studies in 2009, said data from her field work give her greater confidence in making recommendations to irrigation producers.
Irrigation development is ongoing in Saskatchewan, where up to 20,000 acres are added annually. Current efforts are focused on developing existing irrigation districts to make use of infrastructure already in place.
