Growers forced to cut back on NPK fertilisers this winter and further forward are being advised to leaf tissue test this winter as crops might already be suffering from nutritional deficiencies.

Chris Bond, commercial technical manager for crop nutrition at FMC, said high prices and short supplies of fertiliser could exacerbate already deficient soil situations this year, with phosphorus and potassium shown to be lacking.

“Through extensive tissue testing at FMC, we’ve seen deficiencies of phosphorus rise from 5% in 2019 to 16% in 2021. We’ve also seen an increase in potassium deficiencies, rising from 31% in 2019 to 54% in 2021,” he pointed out.

“With the shortages of NPK fertilisers, phosphorus and potassium deficiencies this year could rise even higher and as a result crops could suffer, particularly in the early stages of spring, when cold and usually wet soils make it even more difficult to access any available nutrition form the soil.

“Phosphorus is an important nutrient for crops as it forms the energy source of the crop as ATP. This means it encourages good establishment and root growth and will be required in the spring to get crops moving again after winter dormancy.

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“Potassium is also vital as it is involved in water management and the transport of nutrients around the plant, improving overall crop quality and health,” he said.

Mr Bond advised growers to work with their agronomist and carry out leaf tissue testing this winter and into the early spring period. “Tissue testing can help to give growers a better understanding of whole crop nutrition at crucial points in the growth cycle.

“If tissue testing highlights crops having a deficiency of either phosphorus or potassium, growers can make foliar applications of the nutrients to top up levels in the plant. Foliar applications can be particularly effective if the crop is struggling to access sufficient nutrient during periods of rapid growth.

“By tissue testing, growers can stay on top of the nutritional requirements of their crops and have a better chance of combatting any issues that arise from NPK fertiliser shortages,” he concluded.