Some species of vegetable crops, such as alliums, are especially responsive to the addition of phosphorus. As such, fertilisers high in phosphorus are often applied as starter fertilisers as an aid to establishment. The high cost of phosphorus-containing fertilisers and the possibility of tighter application restrictions intent on protecting water courses, has stimulated interest in technologies that improve the availability of phosphorus reserves in the soil.

Agrii Release is a cation complexing agent, which when applied to the soil surface, has been shown to improve phosphorus availability by breaking the bind between metal ions in soil and phosphorus molecules. These ions attach to the phosphorus molecules making them unavailable to the plant. The Agrii trial sought to establish whether the use of complexing agent would work in much the same way as seen with water conditioners used to treat the effects of hard water.

To investigate the potential Agrii Release, crop screening trials were conducted in the 2021 season.

“Soil analysis performed post-application revealed increases in the available phosphorus. This served as confirmation of its potential. The next stage was to assess the benefit to treated crops,” David Townley, Agrii agronomist who oversaw the trial says.

In 2022, Agrii Release was applied at the standard rate of 4 litres/ha to a commercial carrot crop in Suffolk.

“The results were impressive. From a modest application rate, treated crops yielded roughly 20% more than the untreated control. This higher yield is principally a result of longer (3 to 4 mm/carrot) and heavier carrots (6 to 7 grams/carrot) in the treated group resulting in a marketable yield 12% more than the farm standard (untreated),” Mr Townley says.

“The drought and high temperatures of summer 2022 clearly impacted gross yield, but the effect of Agrii Release was reassuringly positive,” he adds.