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Ontario Grain Farmer Magazine is the flagship publication of Grain Farmers of Ontario and a source of information for our province’s grain farmers. 

Maximizing fertilizer usage this spring


it’s been a year to celebrate in Ontario, with outstanding yields for corn and solid yields for soybeans and wheat. However, with great yields, comes great responsibility. Growers must be careful to ensure soil fertility is adequate for next year’s crops, while keeping an ever-vigilant eye on the bottom line. 


“I can’t endorse soil tests enough,” says Ross Stone, a certified crop advisor of Perth Ag Partners agricultural input supplier in Listowel. “Without soil tests as a reference point, you have no way to decide how best to spend your fertilizer dollar.” Adding fertilizer to fields based just on what’s been removed by the crop is not a wise way to manage your soil fertility. “Yes, you’ll be adding nutrients back,” Stone asserts, “but it could very well be that all you are doing is maintaining an excessive or deficient fertility position; soil test to get a benchmark.”

To minimize fertilizer usage, it’s also critical to carefully examine soil test results field by field. “You should absolutely identify similar fields or areas and treat them differently than others, if results warrant,” states Stone. “You will reduce inputs on some areas of your farm and make sure yields are maximized in other areas by adding more nutrients that you perhaps believed were needed.” Soil pH can also affect the availability of major nutrients as well as micronutrients, so Stone says taking a close look at pH test results in each field is also worthwhile.  

Along with high yields, the 2010 season was also exceptional in terms of more reasonable phosphate and potash prices. “Some growers had previously cut back on the P and K they were using, but many already played catch-up this fall,” Stone says. “And with fertilizer prices expected to continue to increase, it’s probably wise to consult with your supplier about the best time to buy inputs.”

Lastly, growers who have not tried the Corn N Calculator at are highly recommended to do so by Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) corn specialist Greg Stewart and many others. The free software provides suggestions for pre-plant N and side-dress N application rates, factoring in soil type, crop heat units, long-term average yield or expected yield, previous crop, futures contract price and cost of nitrogen.

technologies put to the test
While there are many new types of fertilizers being marketed, “most of it is variations on an old theme, or else totally unproven and therefore suspect,” says Keith Reid, OMAFRA’s soil fertility specialist. Most of the biologicals and amendments fall into this latter category, he says, and few companies are even bothering to pursue registration for these products under the Fertilizer Act, which is a legal requirement for selling fertilizers in Canada.

Agrium’s ESN is a relatively new N-delivery technology that contains a urea granule within a micro-thin polymer coating. It allows water within the soil to move into the granule and dissolve the urea, which moves in solution into the soil. Reid says the concept here is that ESN can help to provide better N response by reducing the amount of N loss. “In short, it’s a risk-management tool more likely to provide a benefit if the farmer’s normal practice includes N applications that would trigger N losses,” he notes. That is, if growers are already managing N to minimize potential losses, the expected benefit from using ESN would be small. “There haven’t been a lot of field trials in Ontario comparing ESN to other N sources, but the few I’m aware of have not shown the same level of yield increase as in the US Corn Belt studies,” Reid observes.

Cargill’s Micro-Essentials product (MESZ) can also fill a niche for some growers, adds Reid. MESZ’s manufacturing process combines sulfur and zinc with a phosphate fertilizer, so that each granule contains all the nutrients. “The trials I have seen would suggest that this doesn’t provide any yield advantage over providing the same nutrients in a blend and it is not going to provide any advantage at all if the field already has adequate sulfur and zinc,” notes Reid. “But, it does provide insurance against segregation of a zinc premix in a bulk blend and, most importantly, it does provide a high level of convenience for the grower.” MESZ is useful to those growers, he concludes, who need supplemental zinc (or sulfur) with their corn starter, but don’t want the hassle of blending different products.

The GreenSeeker, produced by NTech Industries Inc. of California, is a technology that is attached to a tractor and uses corn canopy reflectance as a means to measure nitrogen requirements to determine where sidedressing may be required. Dr. Bill Deen, a professor in the Department of Plant Agriculture at the University of Guelph, has tested the Greenseeker at various leaf stages on commercial corn fields. “We found that growers that use technologies such as the GreenSeeker are as likely to over-apply nitrogen as they are to under-apply,” says Deen. 

For those growers who are attentive to their soil, fertilizer and production costs – in the case of soybeans and corn in particular – Stone believes the future looks bright. “There is more demand than is produced,” he stresses, “so careful growers should thrive along with their crops.” •


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