Protected fall N improves efficiency

Nitrogen stabilizer products have a good fit where farm labour and time are limited

Dan Hacault likes to use nitrogen stabilizer products on his farm for time management, convenience, nutrient efficiency, cost effectiveness, and making it easier for him to manage seeding when working by himself… and oh, yes, on-farm field trials show his yields are holding steady as well.

Hacault, who has downsized to crop about 1,300 acres near Swan Lake in south-central Manitoba, has been working to improve input and time efficiencies on his farm for several years. He was one of the early adopters of variable rate fertilizer technology.

Now, to further improve time and input efficiencies, he has also switched to fall-applied nitrogen using two different nitrogen stabilizer products. He hires a custom applicator with a float to apply granular Super U (46-0-0) nitrogen and for other parts of the farm he also uses his own equipment to apply liquid eNtrench from Dow AgroSciences.

“We are farming fewer acres, and it is hard to find labour, it just made it much more efficient to apply the nitrogen in the fall,” says Hacault. “But because nitrogen losses can be high I wanted to use protected fertilizer products.”

Aiming to have the products applied about mid-October, Hacault used banding equipment in 2014 to apply eNtrench to about 200 acres of land to be seeded to canola in the spring of 2015. At spring seeding he placed granular phosphate with the seed and sidebanded liquid sulphur. Super U was float applied to the remainder of his crop acres also in the 2014 fall. The nitrogen stabilizer component is actually injected inside the Super U prill. It can be fall applied to the soil surface without incorporation.

With the liquid eNtrench nitrogen, side banding places it in the top two to three inches of the soil profile. Hacault says research shows even though the nitrogen is banded, there is still risk of nitrogen losses when shallow banded if unprotected fertilizer is used.

Hacault says so far he hasn’t seen where one product has a better fit than the other. “Having the granular product float applied is very convenient,” he says. “They can do the whole farm in a day and a half. But the Super U is considerably more expensive than the eNtrench product.”

Hacault had most of his acres treated with the granular nitrogen in the fall of 2015, but will be spring-applying eNtrench nitrogen to part of his farm at seeding in 2016. “I also found the products worked equally well with all crops,” says Hacault who this year is producing hybrid rye, oats for a contract market in the U.S., canola and some wheat.

He has conducted his own on-farm strip trials to see if there is any measurable difference according to the combine yield monitor. One recent trial compared eNtrench against Super U against a spring-applied unprotected liquid nitrogen. “We had the three different treatments and all performed equally well,” says Hacault. “I mainly wanted to see if there were any nitrogen losses with these fall applied products. And as far as the yield monitored showed all were equal. The protected products did exactly what the literature says they will do. In this area with soil and moisture conditions we can have as much as 60 per cent nitrogen loss mainly due to leaching, so if you can protect that nitrogen that is quite a savings.”

Dr. Rory Degenhardt, Dow AgroSciences (DAS) research scientist says the nitrogen stabilizer products have the best fit in areas where moisture and environmental conditions are most conducive for nitrogen losses. “In higher rainfall areas leaching and denitrification can certainly be an issue,” he says. “And it can also be a concern on irrigated land in the brown soil zone. Losses can vary from area to area and from year to year, but losses in the 10 to 50 per cent range are not uncommon.”

DAS actually produces two nitrogen stabilizer products. eNtrench is a liquid nitrogen product, while N-Serve can be used with anhydrous ammonia. Both products are designed to do the same thing, which is to slow the conversion of ammonium nitrogen to the nitrate form. Nitrogen is quite stable in the ammonium form, but with the combination of moisture and warming temperatures eventually it converts to nitrite and then to nitrate. And in the nitrate form it is vulnerable to leaching and denitrification losses.

Degenhardt says the stabilizers in eNtrench will certainly protect it over winter and will gradually release with warming conditions in the spring, usually having some influence until early to mid-June.

Hacault says he is looking to be as efficient with crop inputs as possible. “Our fertilizer bill hasn’t necessarily gone down but now we are getting improved yields on the most productive acres and not loosing nutrients to the environment.

“And when you look at these nitrogen stabilizer products, on one hand they are more expensive, but when you consider your time, and equipment, getting the crop seeded in a timely manner and potential for nutrient loss, I really believe the cost is about the same, and perhaps even offers some savings.”

About the author

Field Editor

Lee Hart is editor of Cattleman’s Corner based in Calgary.

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