Results from YEN Nutrition shows that over 80% of crops submitted have nutritional concerns, as ADAS warns that farmers can no longer afford ‘guesstimate’ crop nutrition.

With fertiliser prices remaining high, and grain prices still rising, crop physiologists at ADAS are urging farmers to measure their fertiliser performance with grain analysis and benchmarking.

Crops primarily require nutrients through April and May when leaf canopies are expanding, and again for high yielding crops through June and July to feed grain nutrient storage. Farmers will need to have established soil supplies or applied extra nutrients in advance of these times, maybe supported by soil and leaf analysis. Therefore, the best time to assess nutritional success is at harvest with grain analysis, which can measure final nutrient capture by each crop and identify if extra nutrition was worth the spend, says ADAS.

Dry spring challenges

The firm’s grain analysis and benchmarking service, YEN Nutrition, has identified that farms often differ in their nutritional success. Most crops submitted for analysis after harvest 2021 – over 80% – had nutritional concerns, with management either being overly generous or consistently stingy with each of the 12 essential nutrients. Lower than optimal levels for nitrogen, sulphur and manganese was evident across the crop samples, leading ADAS crop physiologists to conclude the dry spring conditions of 2021 may have limited the crop’s ability to absorb adequate nutrition.

Grain phosphorus and potassium on the other hand was found to be variable and mainly less than assumed in RB209 (5.5 kg/t K2O). It can be estimated that farms with land needing maintenance dressings (soil P and K less than Index 3) benefited by £100 per average 10ha field in 2021. With current 2022 prices, that benefit rises to £350, they add.

Farm-to-farm variability

ADAS says that through benchmarking, it was clear that farm-to-farm differences were significant for N, P and K concentrations in grain, as well as for grain yield. Surprisingly, little variation in grain nutrients was explained by soil analysis (pH, P, K, Mg) showing how important grain analysis is for telling growers the whole story of how their crop and soil management affects their crop’s ability to capture each nutrient.

“The 2022 price hikes for both fertilisers and grains have massively increased the importance of getting nutrition right field by field,” says Roger Sylvester-Bradley, head of crop performance at ADAS. “Grain analysis can now identify whether any particular nutrient was limiting in any crop and benchmarking can show what the causes were. Putting these together could now transform most farms confidence in profitable crop nutrition.”

Roger says that they estimate average financial uncertainties in fertiliser decisions are now around £2,000 per field. “But you can’t manage, or improve, what you don’t measure, and compare. So why not check whether fertilisers have worked?”