Crop Scene Investigation - 36 Solved: The case of the disappearing nitrogen

Monday, February 20, 2012

by BERNARD TOBIN

Kelvin had indeed followed agronomist Paul Sullivan's advice and applied the nitrogen his soybeans needed after they failed to nodulate. Unfortunately, an application error caused the nitrogen in one field to be spread only on 15-inch strips in the field.

As Kelvin explained to Sullivan, the fertilizer apron on the spreader, which delivers the fertilizer to the spinner, is controlled using the tractor's hydraulics. The spinner, which spreads the fertilizer across the field, is powered by the PTO. As Kelvin moved from field to field, he would cut power to both the apron and the spinner after finishing a field and then move on to the next field.

Unfortunately, when he entered the field in question, Kelvin restarted the apron but forgot to engage the PTO and restart the spinner. As a result, the fertilizer simply poured out in a 15-inch strip behind the spreader as it travelled the field. The soybeans in the strips received the nitrogen they required, and produced what looked like test strips of healthy, green soybeans in the field, while the majority of the crop was left nitrogen-deficient.

"We chalked it up to operator error, but the important message here is for growers to scout those first-time soybean fields to ensure they're nodulating," explains Sullivan. "When there's no nodulation, nitrogen needs to be applied.

As this field showed, there is a significant response to nitrogen and the crop will be better for it." Congratulations to John Coleman, Kippen, for his correct answer. In his response Coleman notes: "Been there done that." BF