Crop Scene Investigation - 43: Why did some of Bill's winter wheat perform poorly?

Sunday, March 3, 2013

by BERNARD TOBIN

Winter wheat can tell you a lot about what's going on in your soils, says agronomist Paul Sullivan. With the growth of winter wheat acres in eastern Ontario, he and his colleagues are quickly learning to look below the surface for clues to what's happening above ground.

"It's a crop that really gives you visual indications of what's going on in the soil," says Sullivan, who followed his own advice last March when getting to the root cause of some poor-performing winter wheat in a field near Kinburn.

When Sullivan first talked with Bill about his meagre wheat, the farmer described how the plants at the top of the 33-acre field were shorter and less thrifty. They also had less top growth and fewer tillers than the plants in the remainder of the field.

The problem extended about 100 metres into the field. At that point, the plants changed considerably with a healthy, vigorous wheat crop inhabiting the rest of the uniform silt loam field.
"Bill thought it was just a case of water laying in that part of the field behind his house and setting back the crop," recalls Sullivan. But, on closer examination, that theory didn't hold up.

"The year before, he had water and ice damage in some fields, but this was different. This area was just too large," recalls Sullivan. "With the location of this field, we thought snow drifts might have caused snow mould that could have set back the crop. But Bill said snow cover was not an issue in many parts of the area in question."

The field had been planted on Oct. 8 with Princeton, a hard red winter wheat. The seed was treated and planted into soybean stubble after a light tillage pass.

"We quickly ruled out anything to do with seeding rate or timing," Sullivan explains. "There was no difference in seeding depth compared to the better part of the field and the bad area did not follow any seeding patterns that we could identify. There were no tillage or residue patterns that could make that kind of impact."

Sullivan also ruled out drainage as a potential problem, noting there was no pattern of water sitting in the field that matched the location of the poorer crop.

He then turned his attention to fertility. Bill planted the wheat with his drill and broadcast fertilizer to ensure the crop had enough starter nitrogen. "The fertilizer application was 23-0-30 at 150 pounds per acre, so we figured that was plenty for the field."

Sullivan was confident fertilizer was not a factor because Bill had applied biosolids to the field. Many of the agronomist's clients have been using biosolids originating from the city of Ottawa and have enjoyed strong crop performance resulting from the high phosphorus levels these products deliver.

An application map is made for every field where biosolids are applied. Sullivan keeps a copy of these maps in the client binders he maintains for each of his farmer customers.

"When I pulled out the map and took a closer look at the application pattern, we suddenly realized what had happened," says Sullivan. "It was obvious why that part of the field was performing poorly compared to the rest of the field."

What did Paul Sullivan see on the application map and how did it affect the wheat crop? Send your solution along with complete contact information to Better Farming at: rirwin@betterfarming.com or by fax to: 613-678-5993.    

Correct answers will be pooled and one winner will be drawn for a chance to win a Wireless Weather Station. The correct answer, along with the reasoning followed to reach it, will appear in the next issue of Better Farming. BF