Dan’s curiosity about his first crop on a new parcel of land quickly turned to concern when he noticed some of the field peas he had planted that spring had stopped flowering. “A section of my field is ripening before the rest of it,” he told me one day in early July last year, “It doesn’t make sense.”
I headed out to Dan’s farm mulling over the details he’d given me. The plants were stunted and appeared to have stopped flowering on roughly 50 acres in the middle of a 350-acre field, he said. Dan, who grows 7,500 acres of wheat, lentils, peas and canola near Herbert, Sask., told me the rest of the field looked completely normal. He thought perhaps herbicide carryover was to blame. That was one of many possibilities we had to consider.
Looking out over Dan’s field of peas, I could plainly see an oval-shaped area of stunted plants. These plants seemed to be ripening, while the rest of the plants surrounding the area were still flowering. The healthy-looking plants appeared to be developing normally when compared with his other fields. I pulled up a few of the plants in the affected area and I noticed they had poor root and nodule development when compared with the healthy-looking plants.
The field had seen its fair share of rain that spring, so conditions were wet, but the field was well drained and there was no standing water. With the exception of the rain, weather conditions had been fair, so frost, hail and wind were not factors in this case. The seed had been treated, and an inoculant had been applied at planting. We concluded the seed could not be the cause of the damage because the plants surrounding the area of concern were healthy and developing well.
The damage to Dan’s field could have been caused by herbicide carryover or possibly drift from a neighbouring field. We examined the field for patterns associated with herbicide drift but we didn’t find any. We then contacted the previous owner for a record of chemicals applied to the field—no residual herbicides had been used over the past few years.
Next we considered the possibility that insects were damaging Dan’s crop. We checked for pea leaf weevils and aphids as well as damage from wireworms and cutworms. We found no evidence of an insect infestation.
Now that we had ruled out all of the other possibilities, we decided to compare the soil from the affected with the non-affected areas. We sent samples of the soil profile from a zero-to six-and six-to 12-inch depth for analysis.
When the results came back, Dan was surprised by what I had to say.
Why have the plants in the middle of Dan’s field stopped flowering, and why is their growth stunted? 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 best answer, along with the reasoning which solved the mystery, will appear in the next Crop Advisor’s Solution File.