5 June 1998

How knee-jerk fert policy can cost you dear

BEWARE the hidden cost of declining fertility caused by simple knee-jerk changes in fertiliser policy, warns John Hollies of the Potash Development Association.

"Effective cost cutting requires careful attention to detail. Just using less is likely to result in serious penalties." Unlike nitrogen, where the effect of using less is seen immediately, losses from inadequate phosphate and potash are less obvious but doubly grave, he says.

"Income is lost from reduced yield and quality. But there is also the ultimate cost of restoring fertility. This is often underestimated."

About 500kg/ha (400 units/acre) is needed to lift a soil index of 0 to 1, says Mr Hollies. "On some soils much more nutrient may be required." Currently that costs £150/ha (£61/acre) and £100 (£40/acre) for phosphate and potash respectively, he estimates.