SWIFT CURRENT, Sask. – Producers who want to use alfalfa in crop rotations should be sure to remove it after three production years, says a researcher from the Semiarid Prairie Agricultural Research Centre here.
Otherwise, the soil moisture will be depleted and forage production will drop off.
“Three years would be a good fit in a rotation,” Russ Muri told a conference.
Producers are looking at incorporating alfalfa into rotations in order to minimize input costs.
Muri said the obvious benefit of adding alfalfa to a rotation is the 270 pounds per acre of nitrogen that it can put into the soil.
The plants’ deep roots can also mine the soil for leached nitrogen from fertilized annual crops previously grown on the field.
Forage crops are competitive with weeds, he said, pointing to a survey of Canadian farmers in which 83 percent reported fewer weeds after an alfalfa rotation. They reported good suppression of wild oat, green foxtail and Canada thistle. Forages can also break up disease and insect cycles.
But the downside is the complete depletion of available water.
