Fertilizer — prepare for worst-case scenario

Post-seeding application is one option, while healthy seed and timely 
spraying can boost crop prospects

Prepare for the worst-case scenario, then things may not be as bad as you think.”

That’s Ray Dowbenko’s advice for dealing with the tight fertilizer situation.

The senior agronomist with Agrium thinks there may be shortages this spring, but not everywhere.

“A lot will depend on your relationship with your retailer and your retailer’s relationships with truckers and the plant,” he said. “If the season is fairly normal and starts in the south and moves north in the usual pattern, we can probably stay ahead of demand. A situation where seeding starts at the same time all through the province will be more challenging.”

Shortages in all fertilizers, except potash, stem from last year when world fertilizer prices, especially for phosphates were low. Then export demand picked up in late winter, and rail congestion hindered fertilizer delivery. As well, an auxiliary boiler at Agrium’s Carseland plant blew up this spring, taking out 100,000 tonnes of urea production.

Dowbenko suggests talking to your retailer about your needs and whether you might have a long or a short wait. Then take another look at last fall’s soil test nutrient levels.

“With last year’s yields, most fields probably don’t have a lot of residual nitrogen,” he said. “But you may have a field or two that didn’t produce as well for some reason. Maybe you can move crops around a bit to put those with higher N needs on fields with a little more soil test N. I’d say use those fields for a crop that needs N earlier in the season.”

This is also a year when good agronomic management pays dividends, he added.

“Productive, well-farmed soils have a good level of organic nitrogen that can be mineralized into plant-available forms during the growing season.”

A cereal such as wheat needs N between the three- to five-leaf stage and tillering to produce to its yield potential. Applying N later pushes up protein content rather than boosting yield, said Dowbenko. Canola, ideally, needs N at the rosette stage before bolting. But it continues to branch and produce pods for some time, so N later in the year would likely push yields up.

“Crops really need nitrogen by about three weeks after seeding,” said Dowbenko. “They can hold on till then. But with delayed fertilizer application, the nutrients need to be available. You have to judge whether to use dry product or a liquid formulation and how to apply it. Dribble banding is one option that may be more efficient than broadcasting. But don’t forget about the potential losses with surface-applied urea.”

Volatilization is worst at high soil temperatures under moist conditions, especially followed by dry, windy weather and in fields with lots of crop residue. Sandy soils with low organic matter, high pH, and high lime content create the conditions for higher losses. Urea is most susceptible, but UAN (28-0-0) is not as stable as ammonium nitrate (34-0-0).

Only a little rain, 2.5 millimetres, is needed to incorporate urea into the soil. But losses from urea applied in July can be more than double those following May application — 88 per cent compared to 40 per cent on zero till. The urease inhibitor, Agrotain, can limit losses, but Dowbenko said he hasn’t seen extra value in SuperU (a urease inhibitor with additives).

Pulses are one way to cut nitrogen needs. Peas, beans or lentils need little nitrogen but they do need inoculant, and JumpStart can help them use soil-bound phosphate more effectively.

If you have to ration fertilizer Dowbenko advises doing everything else you can to support the crop.

“Use healthy seed, even screen for bigger seeds and seed by target plant population, especially for canola,” he said. “Seed to the perfect depth and don’t skip any herbicide or other pesticide. A crop with limited nutrients will be more susceptible to disease and competition from weeds, slower to close the canopy, and lose more moisture from bare patches. Use every management tool to do the best you can to compensate for that nutrient shortage.”

There is one small benefit from this year’s tight supplies, said Dowbenko.

“This year is really a wake-up call for farmers,” he said. “We’ve been saying for years that they need more on-farm storage for fertilizers. It saves money because spring prices are always higher, but lack of storage really leaves you at the mercy of logistics.”

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