21 June 2002

Beware cuts in N

PLENTY of scope remains to cut phosphate and potash use, but be very wary of over-economising on nitrogen, warn leading nutrition experts.

Far too many growers still fail to trim P & K dressings where soil indices are clearly high enough to support cereal production without downsides, says IACR-Rothamsteds Johnny Johnston.

But nitrogen is a different story, says Ecopts Ian Richardson. Using optimum nitrogen typically doubles crop output. So even if wheat dips as low as £50/t ammonium nitrate costing £115/t still gives a £3 return for every £ spent at optimum rates, he calculates.

Growers trying to economise should concentrate more on applying it correctly and targeting it properly, Mr Richards suggests.

Where variable rate applications were linked to crop need last year yields were 6-7% higher, notes Yorks farmer and contractor Clive Blacker. "And overall we used 10kg/ha less than before. There is huge potential for reducing input bills." &#42