21 July 1995

Custom spreading for precision input

IF YOU want to reap the benefits of precision input systems, use US-style custom fertiliser spreading services.

The amount of data needed to govern inputs "on-farm" will swamp most farmers. "Instead it needs processing centrally by companies with the necessary crunch capability," says John Mann, president of American precision input company Soilteq.

A wealth of information including soil sample results, soil type, topography, water-holding capacity and fertiliser types has to be loaded into computers to come up with accurate nutrient maps and fertiliser recommendations.

Add to that several years of yield maps for a reliable guide to progress, and most farmers "wont want to mess with it", he says.

"Were going to have more data than we know what to do with. Most farmers will say heres my yield map. Youve got the soil map. Now go and make sense of it."

That information could go on a disk for the farmer to direct his own tractor-mounted hardware. But Mr Mann believes the cost and necessary training would be prohibitive. "Each on-board computer costs £4750. And training even full-time operators takes a huge amount of time."

Rotational tool

Customised dressings may not be needed every year, adds Richard Cartwright of Hants-based SOYL. He believes farmers will want to use his machines as a rotational tool, to correct deficiencies of immobile nutrients like P and K. Farm machines will apply standard dressings in the interim.

&#8226 Legume yield maps are being used to predict residual nitrogen supply to following crops in the US. "There is a direct correlation between yield and residual N," says Mr Mann. It could be adapted for peas and beans in the UK, he suggests.