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

Wednesday, April 3, 2013

by BERNARD TOBIN

Bill's poor-performing winter wheat was planted in an area of the field where biosolids were not applied. The crop was basically suffering from poor nutrition.

When agronomist Paul Sullivan looked at the biosolids application map for Bill's wheat field, he immediately noticed that the phosphorus-rich biosolids cake had not been applied to an area that stretched 100 metres into the field behind Bill's house.

"The setback rules for biosolids application dictate that a 100-metre buffer needs to be maintained from water wells and that's exactly what we had in Bill's case," says Sullivan. That meant that the wheat planted in the remainder of the field was showing a fertility response to the biosolids and significantly outperforming the crop planted in the buffer strip.

Sullivan's diagnosis was confirmed when a soil test revealed the buffer strip contained nine parts per million for phosphorus while the rest of the field tested at 30 PPM. "Once I saw the results of the soil test, I figured that had to be the cause of the problem."

Sullivan says that what happened in Bill's field is a good example of what he's been hearing from Peter Johnson, wheat specialist for the Ontario Ministry of Agriculture and Food, on the importance of phosphorus in wheat.

"Peter maintains that putting on phosphorus can make a big difference in the crop, while additional potash can have very little impact," adds Sullivan. "We certainly saw that in this case. The evidence was right there for the eyes to see."

Congratulations to John Nyman, Picton, for his correct answer.

Crop Scene Investigation will return in the fall. BF