CF CropTec Focus on Encouraging Greater Understanding of Fertiliser Use Efficiency (NfUE) and Soil Testing

Helping growers understand more about Nitrogen Fertiliser Use Efficiency (N f UE) and the critical role of accurate soil testing in optimising N applications was the main focus of the CF stand at CropTec 2019.

In 2019 farm trials, the combined approach has delivered increases in margin over fertiliser costs (MOFC) of £280/ha in some crops whilst in others 10% higher yields have been seen from 15% less N, says the company’s arable agronomist Allison Grundy.

“Whether you look at it from a production efficiency or environmental point of view, getting the most out of bought-in fertilisers will be one of the most important management areas UK growers will face in the coming years.

“Keeping N applications to the economic optimum required to deliver yield and quality whilst achieving the maximum return on investment is a key objective for all growers and understanding N f UE and the importance of soil N supply is absolutely fundamental to this.”

In simple terms, N f UE is a measure of Nitrogen fertiliser recovered by the crop, she explains

“N f UE gives growers a valuable picture of how much Nitrogen fertiliser is actually used by the crop and an insight into the impact their fertiliser choices are having on their production efficiency.

“It can also highlight where potential environmental concerns might lie which is an increasingly important factor in modern production.”

Trials have shown ammonium nitrate (AN) convincingly outperforms straight urea in wheat production in terms of N f UE with an average value for Nitram (34.5%N) of 74% compared to just 66% for urea, she says.

“This difference of 8% N f UE is the equivalent of an additional 16% total loss of Nitrogen from urea and in crops with an application rate of 200kg/ha N this would be equivalent to a loss of 32kg/ha N.

“In other words, simply using Nitram resulted in crops recovering an extra 16% or 32kg/ha N than they would have done with the same application rate of urea.”

As well as making the correct fertiliser choice to maximise N f UE, understanding the contribution soil N is making to crops is also critical, Allison Grundy adds.

“Unlike conventional soil N tests, CF N-Min measures not only the Soil Mineral Nitrogen (SMN), the amount of Nitrogen in the soil at the time of testing, but also accurately predicts

Additionally Available Nitrogen (AAN) which is what will become available to the crop between the spring and harvest.

“Adding these to an estimate of N already contained in the crop gives a true picture of Soil Nitrogen Supply (SNS).

“This can then be used with CF N-Calc to produce fertiliser recommendations based on yield and quality aspirations whilst minimising the potential environmental impact and ensuring the investment in Nitrogen is made full use of.”

Combining the commitment to improve N f UE with N-Min can have a significant effect on margins too, she says.

“In 2019 trials alone, we’ve seen this approach increasing margin over fertiliser costs by £280/ha in oilseed rape and adding 1.0t/ha to wheat yields.

“In Spring barley we’ve seen a 10% lift in yields combined with a corresponding 15% drop in N requirement.

“It’s a relatively simple way for growers to increase their own production efficiency and help industry meet future environment objectives.”