On a cropping property, nitrogen fertiliser is usually the biggest single input cost, so the decisions you make about it each season add up quickly. Rate, timing, placement and source are the levers agronomists usually talk about when nitrogen management comes up, and each of them affects how much of what you apply turns into yield in place of loss.
Research backed by GRDC puts a figure on that loss, with average nitrogen use efficiency in Australian dryland cropping at around 40 per cent, which means more than half of what is applied never reaches the plant. It leaves through pathways like leaching, volatilisation and denitrification, and every one of those pathways shows up somewhere in your fertiliser records and, from there, in your emissions report.
That is why the same paddock decisions affect your emissions figures as well as your costs. Nitrous oxide lost from synthetic fertiliser is one of the standard inputs behind an on-farm emissions report. It carries a lot of weight in the calculation because gram for gram it has around 270 times the warming effect of carbon dioxide. Even a modest volume lost to the air can move your figures more than its size on paper would suggest.
What makes this useful to know is that improving nitrogen efficiency does not have to wait on a new product or a new technology. It starts with understanding a paddock well enough to see which lever is most likely leaking value in a given season, and adjusting from there. A good deal of money is going into the product side as well. GRDC’s ten-year, $115 million Nitrogen Mission is backing research into enhanced efficiency fertilisers and their potential to cut on-farm emissions while lifting how much nitrogen reaches the crop, and the levers on your side of that work are available now.
A Ruminati emissions report is calculated from records you already hold, fertiliser use among them, set against the national agricultural emissions guidance. That gives you a way to see the effect of better nitrogen management across seasons, this season’s figures measured against next season’s, whatever combination of rate, timing, placement or source gets you there.
