Corn growers concerned about nitrogen loss

Tuesday, June 7, 2011

by BETTER FARMING STAFF

It has been a challenging start to the growing season but most growers across Ontario have likely finished planting corn, says the province’s corn expert.

Greg Stewart, the Ontario Ministry of Agriculture, Food and Rural Affairs corn industry lead, estimated Monday that about 85 per cent of the province’s corn crop had been planted.

Farmers east of Toronto intent to get that final 30 per cent into the ground “certainly could have,” says Stewart. In areas where heavy clay soil predominates, such as in the Niagara region and Southwestern Ontario, “I’m thinking they’re still going today (Monday).”

He says farmers have been calling the province’s CropLine with some concerns about corn planted mid-May or earlier that didn’t come up very well after sitting in saturated conditions.

The level of the residual nitrogen supply for crops planted around May 9 is another frequent question: How much of the nitrogen applied around that date might have disappeared?

Stewart says he’s not concerned about the disappearance of the nitrogen supply so much in lighter soils, ranging from loam to sand, as he is in really heavy soils that sat in saturated conditions.

That’s because in Ontario, “a lot of our nitrogen gets lost from saturated conditions where it goes through denitrification and goes off as N2 gas.”

To estimate the loss, he recommends taking soil nitrate samples once the field has dried out “and try to get a feel for, Are we low, medium or high in terms of the amount of nitrate that we’re seeing in the profile?”

At least the sampling will “gives you some sort of a place to start,” he says. BF