Many arable farmers would benefit from switching autumn phosphate and potash applications to the spring, according to fertiliser manufacturer Yara.

That was just one of many messages behind the launch of Yara’s ACTYVA, Active Crop Nutrition Programme for Arable Crops.

Fertilisers continued to be highly cost-effective inputs, said the firm’s Mark Tucker.

For every pound spent on ammonium nitrate at 52p/kg to satisfy the needs of wheat and oilseed rape, growers could expect returns of £4.87 and £4.04 respectively at May 2009 crop prices.

Nutrient use

But there was still plenty of scope for improving overall nutrient use through better product choices, application rates and timings, Dr Tucker explained.

“We’re talking risk management – not risky management,” he said.

In particular Dr Tucker questioned growers’ practice of applying P and K in the autumn. “I reckon 85% apply theirs recreationally from July until the autumn.”

That was really only necessary on soils with indices below 1, he explained.

The better and environmentally safer option, avoiding possible phosphate lock-up and run off as sediment and potash leaching, was to apply those nutrients when spring kick-started crop growth – 70% of phosphate uptake occurred in just four to eight weeks then, he pointed out.

Returns

A switch to spring dressings could boost cereal and oilseed returns by up to £52/ha and £12/ha, trials showed.

ACTYVA brought together a wide range of information based on the company’s 50 years research into crop nutrition.

Reinforcing the potential for growers to improve their use of micronutrients Dr Tucker pointed to leaf analysis data from Yorkshire Lancrop laboratories.

These showed 57% of wheat crop samples analysed had less than optimum levels of potash. The picture in oilseed rape was even worse, 90% being below optimum for magnesium and 72% being deficient in boron.

“If you get it wrong you don’t necessarily see deficiency symptoms. But put affected plants besides healthy ones and the difference becomes very clear.”

Benefits

Other potential benefits of adopting the ACTYVA strategy of minimising risk and maximising return included an extra £40/ha through “little and often” sulphur supply.

Applying nitrogen to oilseed rape at flowering had given an average net return of £73/ha over the past four years.

The use of precision tools such as the firm’s N Sensor offered increased yields worth up to £122/ha.

However, better use of nutrients was about more than money, noted Dr Tucker. Reducing losses to the environment would help growers meet future compliance demands, he suggested.

“As we move forward efficiency of use will become more and more important.”