Advanced fertiliser boosts potato yield and quality

New fertiliser technologies that match nutrient supply more closely to plant requirements through the growing season can increase potato yields – and improve tuber and skin quality.

Controlled release fertiliser (CRF) technology can increase nitrogen use efficiency (NUE) and reduce the carbon footprint of production while polysulphate-based  potash fertilisers have been shown to increase yields and consistency of tuber size.

“These are exciting results for UK potato producers,” says agronomist Scott Garnett from crop production specialists ICL Growing Solutions.

“Faced with the need to optimise use of crop inputs and produce high yields of top quality potatoes in the most cost-efficient way possible, these new trials suggest fertiliser choice can have a major impact on productivity and environment.

Multi-nutrients

“Polysulphate is a naturally occurring multi-nutrient fertiliser mined from underneath the North Sea that when boosted with potassium to produce PotashpluS has the formulation of 23% SO3, 37% K2O, 8% CaO and 3% MgO.

“One of its unique properties is that it has prolonged release characteristics that deliver nutrients in line with the potato plant’s specific nutrient needs over critical stages of the growing cycle.

“In UK trials, where PotashpluS and muriate of potash (MOP) were applied to provide the same 340kg of K2O/ha application rate of potassium to potatoes, PotashplusS delivered an 8% increase in yield over MOP.

“This is attributed to the soluble magnesium, sulphur and calcium supplied by PotashpluS, even when the soil was not magnesium deficient.

“The tuber dry matter was higher in the PotashpluS treatments at 20.6% compared to the 19.8% when MOP was applied and this is a significant improvement when it comes to ease of processing potatoes. The PotashpluS potato tubers were also judged to be more consistent in size, showing less variation.”

CRF technology has proven itself in commercial potato production and independent trials, says ICL speciality fertiliser manager Andrew Judd.”

Optimum delivery

“Unlike other fertilisers, CRFs are designed to release optimum daily quantities of nutrients to crops over a specific timescale.

“This ensures nutrient availability can be matched to the specific crop requirements more effectively, which leads to higher NUE and reduces nutrient losses.

“Another major advantage of CRFs is that they can reduce the number of fertiliser applications required through the season. This reduces farm traffic, labour costs and time as well as helping to reduce potential soil compaction problems.

“This combined with other environmental benefits, such as reduced nutrient leaching, mean CRF could play a key role in helping UK potato production meet its future sustainability goals.”

CRFs works by covering granules with a semi-permeable coating that allows water to pass through it to dissolve the nutrients contained within, he explains.

“The process is temperature sensitive. As soil temperature rises, cracks develop in the coating, drawing in water to dissolve the nutrients inside.

“The water then carries these out into the soil for the plant roots to take up. When soil temperature decreases, nutrient release slows down.

“The continuous release of nutrients through the main part of the growing season when plants need them most, means only one application of CRF is usually required compared to the many often needed with conventional fertilisers.”

Proven results

In one particular trial in Belgium, a 26% increase in potato yields for CRF compared to the grower’s usual ammonium nitrate (AN) based regime was recorded, Mr Garnett adds.

“In other trials in Holland, the income gain from such benefits was 14% for CRF compared to a conventional CAN-based two-application approach and we’ve seen similar yield lifts over regimes using urea treated with DMPP nitrogen inhibitors.

“Furthermore, independent analysis of 19 trials in Holland showed the combined benefits of CRF technology to reduce the carbon footprint of potato production by 11%.”

Similar results are now being repeated closer to home with major lifts in productivity, financial performance and environmental benefits seen in UK trials, says Mr Garnett.

“One UK trial carried, for example, showed the controlled release of nitrogen from CRF increased NUE to 82% and boosted seed potato yield by 10%, delivering an extra £736/ha compared to the grower’s standard AN-based practice.”