MIAMI, Man. – Perry Gemmill’s first experience with field mapping and variable rates came in 2005 when he contacted Farmers Edge Precision Consulting, a new firm in Pilot Mound, Man.
Gemmill, who farms 1,600 acres about eight kilometres from Pilot Mound, had read about variable rate and prescription maps and decided it was time to take the plunge.
He contracted with Wade Barnes from Farmers Edge to make zone maps of the entire farm. The map of his east-west half section field designated as N 33-2-11 is typical of many fields on the farm. Gemmill said this map has taught him a lot in just two years.
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“It’s very flat land. Just looking at it, you wouldn’t think there could be so many variations. There are spots where we had been putting on way too much fertilizer and other spots where we were far below our potential yield because we weren’t using enough.
“But, you know, field maps and data are only as good as the guy reading them. Otherwise it’s just pretty pictures. You need a good guy to interpret the maps.”
Gemmill apparently made the right choice of who could interpret the maps because in March 2006, the Prairie Certified Crop Advisor Board named Barnes the CCA of the year.
Gemmill said he used to put down 80 pounds of nitrogen straight across the whole field. He now uses different rates for the eight colours in his zone map for N 33-2-11.
“This makes so much more sense. Wade showed us that 80 lb. was far too much in some zones and not nearly enough in other zones.
“We had been soil sampling for years with GPS, so we could always hit the same spots. We’d get a bunch of samples together from one continuous field like this and mix them all together in the pail. Now, how much sense does that make? One sample site can throw off the entire field recommendation.”
Gemmill still uses GPS, but now it guides him to the sample sites in his management zones.
“So now we have zones where we’ve cut back to zero fertilizer, with no drop in yield. We had been wasting a lot of fertilizer over the years in those zones.
“And we’ve got zones where we had no idea before how good the soil could be. We’re up to 130 lb. of N in those zones and getting higher yields. It’s a more logical way to distribute fertilizer across the field.”
Gemmill thinks the only way to realize the full benefit of variable rate is with a combination of cost savings in some zones and increased production in others. One or the other will not give the necessary economic benefit.
He is now fully variable rate with nitrogen across the whole farm, but is not yet set up for variable rate on other nutrients. However, he has cut back on phosphate across the whole farm because of the information from Farmers Edge and he has eliminated some other fertilizer costs.
“Last year I had 700 acres of canola and the soil test called for 20 lb. of sulfur on 100 acres of it. We looked at the data and made a decision not to apply sulfur. Then in late June or early July, Wade did tissue tests in that 100 acre spot and the results said we had no sulfur deficiencies.”
Gemmill said those are the kinds of savings made possible by field mapping, reading the data and using better management.
