2 February 1996

MANURE CAN POLLUTE SO BE CAREFUL

MAIZE ground is commonly used to dispose of large volumes of slurry and muck because the crop tends to be grown on lighter land and the fields are fallow late into the spring. But when too much manure is applied serious leaching and surface run-off losses of nitrogen and phosphate may occur.

Ken Smiths advice is to follow MAFF Codes of Good Agricultural Practice to avoid pollution and check efficient use of nutrients supplied by manures.

The best time to apply manures to avoid pollution is in early spring, he adds. Manures applied before December are likely to suffer nitrogen leaching losses during the winter. This may cause significant pollution and may be further aggravated unless the nutrients supplied are taken into account adequately when calculating further fertiliser needs.

"Much of the land that maize is grown on is accessible for field operation for a lengthy period in the spring," he says. "A strategy for applying muck prior to the main cultivation is sensible.

"When manure is applied in late winter or spring losses are small. So providing you know the analysis of the material supplied it is relatively easy to estimate what is available to the crop," he says.

He claims that failure to supply enough nutrients is rare. This also applies to magnesium, sulphur and manganese which need be applied only when a specific deficiency is identified. &#42