Improving Nitrogen Efficiency

Fertilizer management can reduce emissions & input costs.

By Emily Croft

Farmers across Canada are seeking clarity for what the fertilizer emission targets set by the government mean for their crops.

In December 2020 the federal government announced targets for the reduction of greenhouse gas (GHG) emissions, including the goal of reducing GHG emissions from fertilizer use by 30 per cent of 2020 levels by 2030.

Many farmers were concerned that these targets would threaten traditional fertilizer use and productivity on Canadian farms.

“I think there’s a lot of confusion out there, on all sides,” says Karen Proud, president and CEO of Fertilizer Canada.

“The bottom line is Canadian farmers do an incredible job. But there are ways they can they do better and there are tools to help. We need to work with the government to make sure farmers have those tools and ability to use them through financials and other incentives.

“Optimizing fertilizer use is the way to go. We need to balance productivity with the need to reduce emissions.”

What does optimizing fertilizer use look like on-farm, and how will it affect crop yields and efficiency?

Emission sources & targets

The 2021 National Inventory Report described the sources of GHG emissions in Canada, attributing approximately 10 per cent to agriculture. The major emission of concern in relation to fertilizer use is nitrous oxide.

farmer collecting nitrous oxide in field
    Examining the benefit of 4R practices by collecting nitrous oxide gas emitted from a field study. -4R IRC Program, University of Manitoba photo

“Any time nitrogen is added to soil it will naturally be transformed by soil organisms and can result in nitrous oxide being produced and released. It’s a natural process,” says Dr. Mario Tenuta, professor of Soil Ecology in the Department of Soil Science at University of Manitoba.

John Heard, a crop nutrition specialist at the Manitoba Department of Agriculture and Resource Development, says that although total nitrogen losses may be small, the emission produced is powerful.

“The agronomically insignificant amount of nitrous oxide emitted by the soils, or from nitrogen applied to soils, is a powerful GHG.

“It is 300 times the equivalent of carbon dioxide if one per cent of nitrogen applied becomes nitrous oxide. An economically and agronomically insignificant amount of nitrogen loss becomes a big number due to that multiplier.”

What does the target of a 30 per cent reduction in emissions really mean?

“It’s a 30 per cent reduction in nitrous oxide, not a reduction in fertilizer use,” explains Tenuta, also noting that the reduction is voluntary.

The remaining concern with these targets is how emissions are measured.

Proud explains that “in Canada we don’t have an accurate picture of what our total emissions are.

“If we looked at data on how farmers use fertilizer, we would likely have reached 30 per cent reduction already because what the government estimates are based on is not an accurate depiction of how fertilizer is used today.”

Tenuta says that the lack of clarity surrounding emissions targets has received some negative feedback.

“It didn’t garner much attention at first but got attention this past spring. Various groups were not happy with the reduction target, but there seems to be some misunderstanding,” says Tenuta.

“Some folks against the emissions reduction target were arguing lack of communication from government and they assumed the reduction would be in fertilizer use. The government clarified that it was not fertilizer use, but it was emissions from fertilizer being added to soil.

“With the current system of accounting, the only way to reduce emissions is basically a reduction in fertilizer use. We know from research that there are many things that farmers can do to reduce emissions, and we need to get those practices into the accounting methodology. But if we wait for the methodology to catch up with reality of farming to reflect emissions better, we will be closer to 2030 and won’t have done anything.”

While farmers wait for a better process for quantifying emissions, what can they be doing on their farm to improve nitrogen efficiency and reduce emissions?

Lower emissions, increase efficiency

A combination of best management practices and new technology can help Canadian farmers get the most out of their nitrogen application.

“The 4Rs are a complete best management practices program that we feel strikes that balance between productivity and reducing emissions,” says Proud.

“The first is right source and is probably the most important. That means selecting nutrients that the plant actually needs. The next is rate. Determine how much of that nutrient the plants need to replenish nutrients in the soil without losing any to the atmosphere.

“The third is right place. Ensure you put fertilizer in the best place for plant to take up nutrients. This includes practices like banding, that place nutrients at root rather than broadcasting.

“The final 4R is right time. That relates to fertilizing at the optimum time of year to provide the plant with the nutrients it needs at the time it needs it.”

Dr. Claudia Wagner-Riddle, a professor at the School of Environmental Sciences, University of Guelph, explains that many new products, practices, and technologies that are being researched to reduce emissions are based on the 4R program.

“Some of our work has looked at something called an enhanced efficiency fertilizer. It has an inhibitor added to slow down nitrogen fertilizer transformation in the soil and it improves efficiency by giving the plant more time to take up nitrogen. That reduces losses that occur when plants aren’t actively taking up nitrogen,” explains Wagner-Riddle.

farmers applying fertilizer to field
    Applying treatments of different enhanced efficiency fertilizers in a field trial. -4R IRC Program, University of Manitoba photo

“It shows lots of potential and there are lots of other researchers looking at it. It averages out to 30 to 40 per cent reduced emissions, depending on conditions.”

Wagner-Riddle says that splitting the timing of application is another approach.

“Some people have termed it a ‘wait and see approach.’ It works in some cases but may be harder on very large farms.

“This is moving from applications that are ‘just in case’ to something more managed, in terms of waiting to see how much fertilizer is really needed. This would look like applying starter at beginning and topping it up throughout the season.”

Another approach is to adjust placement of the fertilizer.

“If you use a blanket rate, you may be overapplying in some places and undersupplying nitrogen in other places. Do more due diligence in how you adjust rate depending on landscape,” says Wagner-Riddle.

“The issue is that we don’t know what the weather will be like. I think we can do a bit of applying just in case while we do more homework on soil type, condition, and observing weather to adjust rates accordingly.”

Tenuta adds that producers should also stay away from early fall applications, explaining that nitrogen added too early has more time to transform and be emitted as gas.

These practices are all applicable on farm, but what are the costs and benefits to the producer?

Is it feasible?

In recent years, crop producers have seen a rapid increase in input costs.

“We saw that with Russian invasion of Ukraine, fertilizer prices doubled, or almost tripled, in some areas. The hit to input costs was massive for our crop growers,” explains Tenuta.

“With a bump up in fertilizer cost, people are saying, ‘If I tweak management, I could maybe save some money.’ It makes a big impact when investment in fertilizer has gone up twice as much, and by changing amount of fertilizer you use you can change bottom line.”

Tenuta says that now that fertilizer prices are increasing, it’s a good time to review how improving efficiency of nitrogen use not only reduces emissions but can save producers money by reducing nitrogen losses.

“Historically, best management practices have been an easier sell to farmers because what's been beneficial for environment was also beneficial for agronomic efficiency,” Heard adds.

But he also explains that some of these practices “are simply an additional cost to the farmer.”

Tenuta recommends taking an approach that balances improved nitrogen efficiency and production.

“With an improvement in nitrogen management, see if you get a yield boost. If yes, then that’s great. If no yield boost is seen, then the farmer needs to think about recovering the cost of that practice.

“If you don’t see an increase in yield, who pays for that increased nitrogen management?”

Tenuta also suggests that producers evaluate if they can adjust rates to account for reduced nitrogen losses.

“We recommend they test and experiment on their farm. If they don’t get yield boost, test out reduction of application by the cost of the practice.

farmers setting up air sample intakes in field
    Valerie Freemantle and Firdaus Sulaiman set up air sample intakes to measure nitrous oxide concentrations in a corn field. This info is used to calculate emissions from the soil. -Claudia Wagner-Riddle photo

“Maybe the practice comes out to five to 12 per cent of the fertilizer cost. Then the farmer can look at decreasing the application rate by five to 12 per cent and see if any yield is lost.”

Proud says that reducing emissions doesn’t have to be a cost to producers and is already used on many farms.

“Using best practices has been shown to increase crop yields by being efficient and really targeting what the crop needs to grow,” explains Proud.

“Over the years we’ve seen increases in these practices being used on-farm. In 2021, we estimated that 58 per cent of acres farmed were following 4R practices across regions we looked at.”

Mark Burnham, a crop farmer from near Coburg, Ont., says he’s been using some of the 4R best management practices on his farm and has seen good results in terms of nitrogen efficiency.

“Right now, we use a Farmers Edge program to do zone sampling on all of our acres, and from that we do variable-rate fertility of all products. We side-dress as well. We are injecting the product into the ground instead of dribbling it on top,” explains Burnham.

“We haven’t really got to the point of using inhibitors, but we are definitely considering it this year with prices of nitrogen being where they are. But we are not there yet.

“Weather plays a huge factor in wheat nitrogen efficiency. If you don’t get the weather you need, then you put 120 pounds out and you don’t get the bushels – efficiency isn’t as great.”

Wagner-Riddle says, “the barriers to these practices so far have been cost, but with the price of fertilizer being what it is and issues with supply, I think more and more farmers are concerned with that and are looking at ways to improve nitrogen use efficiency.

“It’s not going to be all overnight and that’s where I think we need to do a better job – as researchers, government, and farm organizations – to communicate to farmers what that means for their farm. Because farms are so different, it’s not like a blanket recommendation.”

As accounting systems continue to improve for emissions from fertilizer use, more incentives and technologies may be developed to ensure that increased efficiency and environmental sustainability are enough to justify implementing best management practices on farms across Canada.

Heard says that the issue is complex and evolving.

“This is new and ongoing research. We can’t go back to textbooks and look for answers on this. Each year we have new data to add, and we have to keep up to current research.” BF

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