As soil temperatures have risen to stimulate crop growth, applying fertiliser at the optimum time is key for nutrients to be available to the plant, when prices have risen to record levels.

Alan MacKechnie, area sales manager at Origin Fertilisers in Scotland, offers some advice for farmers and growers looking to apply nutrition in the coming months.

Set the fertiliser spreader correctly

Straight nitrogen has been imported from a wider pool of countries due to the reduced production of nitrogen late last year in Europe and GB as a result of the high gas prices. Therefore, there is the increased risk of greater variability in granule colour, size, density, and crush strength – all of which affect the ability of the fertiliser to be spread across the desired area.

Consequently, farmers and growers may need to give more attention than normal to setting spreaders and be willing to tweak them if the product isn’t reaching the intended target. Gaining the best return from valuable nutrients requires expert advice, hence checking and calibrating spreaders for each product using calibration experts such as SCS, will be vital.

Sulphur key to making the most of nitrogen

Mr MacKechnie added that if straight nitrogen was secured when prices began to rise earlier in the season, it is still not too late to incorporate sulphur into a fertiliser programme to improve nitrogen use efficiency and add valuable nutrition to crops.

An application of 100kg of polysulphate (48%SO3, 14K20, 17%CaO, 9%MgO) would supply around 48kg of SO3 to the growing crop over the course of the season – enough for most cereal crops according to RB209. An application in May will still enhance the uptake of nitrogen as opposed to no application at all.

Sulphur, he said, is an essential nutrient that is key for protein formation and has a direct influence on improving crop quality. Crops with high nitrogen input tend to have increased sulphur requirements as it helps plants use nitrogen more effectively, hence overlooking sulphur will lead to some of the nitrogen applied not being available to the plant.

Broad-spectrum analysis can offer greater insight

Furthermore, if fertiliser has not yet been purchased, it is not too late to invest in a broad-spectrum soil analysis so that only deficient nutrients can be bought rather than spend on nutrients that are already at optimum level.

Mr MacKechnie added that farmers should remember Liebig's law of the minimum, which states that yield is proportional to the amount of the most limiting nutrient, whichever nutrient it may be. If the level of the deficient nutrient is increased, yields may be improved such that another nutrient becomes yield limiting, which can then be rectified in following years.

Be guided by a FACTS qualified advisor

Farmers and growers should check crop growth and look at the weather regarding applications timings. Seeking advice from a FACTS qualified adviser will help ensure plants are at the correct growth stage to make the most of nutrition.

With historic high prices, the guiding principles of the ‘4 Rs’ are more important than ever for planning fertiliser applications: Right product, Right amount, Right time and Right place.