Bill, a farmer who grows 3,000 acres of wheat, barley, oats and canola south of Melfort, Sask., had acquired another quarter in the spring of 2011. The new quarter had a history of canola-cereal rotations with canola yields in excess of 40 bushels per acre. Bill had high hopes for a great return on his new investment when he seeded the quarter with canola that spring.
Bill began to suspect something was wrong at the beginning of June when he noticed the leaves of the two-leaf-stage plants were cupping and the leaf margins were turning purple. As the crop progressed to the four-leaf stage, the symptoms appeared to be worsening. “My crop looks sick,” Bill told me during a phone call in mid-June. He asked me to visit his farm to confirm what he thought was a chemical injury to his crop. “Could be a drift problem,” he said.
Bill’s crop looked sick. Although the whole field was affected to some degree, the symptoms were more severe and occurred more often on knolls and hilltops than lower-lying areas.
Chemical drift could not be responsible for the damage, I told Bill, because of the widespread nature of the symptoms throughout the field. Although certain herbicides can cause symptoms in canola plants that are similar to those we were observing in Bill’s field, records indicated that herbicide injury due to residuals in the soil was also unlikely. However, I thought examining the field’s history might turn up some clues to explain the plants’ leaf cupping and purpling.
The soil was sandy loam, and Bill had applied a 90-25-0-10 blend fertilizer on the field — fairly standard for the area. It had been a wet spring, so at this point we couldn’t rule out a problem due to saturated soil. However, because the symptoms were more severe on the hilltops, this scenario was also unlikely.
The key to solving this casebook, I thought, was in these details — a historically high-yielding field with sandy loam soil and a canola-cereal rotation. What Bill was experiencing in his field was also a growing problem in many other fields across Saskatchewan and Alberta.
“You’ve got to act,” I said. “This problem is only going to get worse if you don’t do something about it.”
Will Bill’s hopes for a bumper crop be crushed? What’s causing the plants’ leaves to cup and the leaves’ margins to turn purple in Bill’s canola field? Send your diagnosis to Grainews, Box 9800, Winnipeg, MB, R3C 3K7; email [email protected]; or fax 204-944-5416 c/o Crop Advisor’s Casebook. Best suggestions will be pooled and one winner will be drawn for a chance to win a Grainews cap and a one-year subscription to the magazine. The answer, along with the reasoning which solved the mystery, will appear in the next Crop Advisor’s Solution File. †