Nitrogen applied to crops that are frosted over do not stay in the soil.

The trial established that relying on nitrogen to carry-over from 2021 was insufficient to meet crop demands, and to maximise grain yield and economic return in 2022 crops needed additional nitrogen to be applied.

Laconik chief executive officer Darren Hughes (pictured) said he received a lot of questions from growers at the time, after their 2021 crop was frosted, what happened to the nitrogen they had already applied.

It was a pressing issue, especially with the price of nitrogen rapidly rising.

"Growers didn't want to waste money that they didn't essentially have to spend," Mr Hughes said.

When comparing grain yields from the carry-over nitrogen treatment to the 'grower standard' treatment, there was a penalty of up to 1.46 tonnes per hectare in wheat and 0.19t/ha in canola.

This translates into an economic loss of $390/ha and $75/ha respectively.

"That loss is pretty significant in a year like last year, you don't get those years very often at all, so you have to maximise profitability when those good years come along," Mr Hughes said.

"The key learning was it is easy to skimp on nitrogen early on in the crop, but our soils are deficient so there should be quite a bit of nitrogen going into 2023."

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He said the assumption by agronomists was that nitrogen carried across, but when he did the soil tests on the sites, 90 per cent of the soils were deficient in nitrogen.

Soil samples were collected in March and July from each site at intervals of 0-10 centimetres, 10-30cm and 30-60cm.

Except for two sites, nitrate and ammonium levels were well below the desired range.

Farmers are encouraged to soil test to see what level of nutrients are in their soil, which acts as an important guide to inform decisions.

"It is a useful guide to give you an indication of how much nitrogen is in your soil, and after all the soil tests that I've seen, there's not a lot of nitrogen in the soil," Mr Hughes said.