Crop Scene Investigation - 54: What did bones have to do with the health of Sylvain's corn?

Tuesday, January 6, 2015

by BERNARD TOBIN

Agronomists use a vast range of knowledge and experience to diagnose crop performance issues. But rarely do they use bones and skeletons to solve the mystery of a poor corn crop.

In late June, DeKalb agronomist Sean Cochrane received a routine request to assess a cornfield and make a replant recommendation. When he arrived at Sylvain's cornfield just east of Ottawa, the agronomist's first task was to walk the field with the farmer and his seed retailer. "The farmer was concerned because the corn was purpling and not responding well in the cool conditions," he recalls.

Sylvain had cleared the 20-acre field the previous year and had low expectations for the first crop, but he was concerned whether the purpling plants would produce anything and whether he should replant.

"It was June 26 when we walked the field and it was indeed virgin ground," recalls Cochrane, who noted burnt wood and large chunks of tree limbs in different parts of the field. "It was exceptionally sandy ground, almost blow sand. Strangely enough, it had very low organic matter for a piece that was fresh ground, so the purpling plants were not surprising."

Typically, purpling indicates a phosphorus deficiency, but Sylvain had applied the recommended levels of N, P and K. That led Cochrane to think the poor performance could be due to the inability of the plants' roots to take up needed nutrients because of the cool, slow growing conditions.

The five-leaf corn didn't look pretty, and yields would be low, but Cochrane felt it was a good stand with even emergence and would be worth keeping. No replant was necessary.

As Cochrane and Sylvain walked across the field, the farmer asked the agronomist for some field management recommendations on how he could get better yields the following year. "That's when we noticed these two spots where the corn was a foot and a half taller than the rest of the corn. I said: 'There's the answer to your purple corn. There's something in those two spots that has provided that crop with what it needs'."

Cochrane's curiosity grew as he approached the first patch of healthy corn. It measured about five feet in length and included two rows of healthy plants. "The soil type didn't appear to change and neither did the moisture – it was the same blow sand. But the corn was green and stood out. It was getting nearer to closing at canopy while the rest of the field was poorly developed."

It wasn't until they were directly on top of the spot and started looking down that they recognized small bones lying right beside and in between the row. Cochrane then walked over to the second location where the corn was also beginning to canopy. This spot was similar in size and, as he began to dig through the soil, he found a similar collection of bones. He concluded that deer had fallen and decomposed on each spot.

As he brushed the sand off the bones, Cochrane explained to the farmer why the corn in the two small patches was thriving, and what he could do to replicate that performance across the field.

Do you know what Cochrane told the farmer? Send your solution and 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