Farmers could significantly reduce phosphorus fertiliser bills and benefit the environment thanks to a novel product that converts unavailable phosphate into a crop-available form.

Many high calcium or high pH soils might appear to have adequate P indexes, but most of this essential nutrient is bound up as insoluble calcium phosphate and is not available to the crop, said Chris Martin, Agrovista’s head of soil.

“Phosphorus is critical for crop growth, playing a key role in cell biochemical functions and cell division. It is required in relatively large quantities during important plant development phases such as seed germination and rooting, as well as flowering and seed production,” he said.

Applying bagged fertiliser can help meet demands, but this can be expensive and inefficient. “Depending on soil type and pH, as much as 90% of P applied in this form can become insoluble and locked up, often within days,” he pointed out.

“If you can make use of what’s already in the soil, you can make significant reductions in both inputs and costs. By applying Phosphorus Liberator, growers can free up significant amounts of P, reducing fertiliser bills and improving efficiency from applied phosphate fertilisers and manures.”

This product contains carboxylic acid, which solubilises calcium phosphate, keeping the phosphate in solution, making it readily available for uptake through plant roots.

The product can be applied through a conventional sprayer pre-drilling, or tank-mixed with a wide range of pre-emergence herbicides at rates tailored to soil P levels and crop need. It is effective over a wide temperature range, is biodegradable and is not classified as hazardous to the environment.

Mr Martin said Phosphorus Liberator could have significant environmental benefits. “Reducing phosphate pollution into water courses continues to be a key driver in the UK meeting Water Framework Directive obligations and if the situation does not improve dramatically, legislation could very easily limit or even prevent phosphate applications across many fields throughout the UK.

“As the regulatory landscape changes in terms of fertiliser use, Phosphorus Liberator could become a go-to tool for those needing to unlock currently inaccessible nutrients within the soil, therefore reducing the reliance on traditional nutritional solutions.”

It is part of the Agrovista Innovation Range of targeted bioscience products.

Trial results:

Assessments carried out on a range of crops this season have reinforced earlier work demonstrating the value of Phosphorus Liberator.

Last autumn, oilseed rape plots treated with it at 10 l/ha had twice the root weight compared with those treated with DAP alone at 165 kg/ha, thanks to a 61% uplift in plant numbers and a 31% increase in individual plant root weights.

In winter wheat, a crop assessment conducted in Suffolk in January, 2020, showed a dramatic increase in rooting when it was was applied, compared with untreated. Root weight was up by 43% at the 5 l/ha rate and by 100% at the 10 l/ha rate.

The effect was still evident the following April. Tiller assessment showed the treated plots (5 l/ha and 10l/ha, respectively) had 1.56 and 1.62 tillers per plant, excluding the main stem, compared with 1.13 for the untreated. Where compound P had also been used, the figures were 1.84, 1.88 and 1.34 tillers, respectively.

Spring beans showed an even bigger increase. Plant numbers rose by 69% and foliar and root weights by 133% and 122%, respectively, when treated compared to untreated plots.

How to use Phosphorus Liberator

• Apply through conventional boom sprayer at traditional water volumes

• Widely tank-mixable with agrochemicals, including glyphosate and many pre-emergence herbicides

• Apply pre planting to early crop emergence

• Apply at 5 l/ha when used alongside phosphate fertilisers or organic manures

• Apply at 10 l/ha when applied alone.