8 September 1995

Dilemma on heavy land

GROWERS with heavy clay soils are on the "horns of a dilemma" when it comes to putting some of the Task Force guidelines into practice, according to NFU pesticide specialist Chris Wise.

Earlier cultivation advice, often based on reduced working, was aimed at maintaining a well-fissured, open soil. This was to improve drainage and aeration for good crop rooting and growth.

Adopting the Task Force advice, like ploughing, could destroy years of work building up that structure, Dr Wise concedes. It could also reduce the already short autumn working window.

Essentially individual growers have to balance the need to control the movement of IPU against other husbandry needs, he says.

Rhone-Poulencs Austin Davies points out that many affected growers have already had to shift to ploughing to incorporate straw after the burning ban.

farmers weeklys midlands barometer grower David Brightman notes that the guidelines refer to ploughing only as deeply as "practical". "On our clays that means shallow," he says.

He subsoils "everything" in the belief that the operation helps shrink the large naturally occurring cracks and creates more widespread fissuring to allow greater IPU adsorption. Running heavy discs over the surface produces a fairly fine tilth to absorb moisture and retain the IPU where it is needed, he explains.

Fine, consolidated seed-beds are needed to retain IPU. But creating them may not always appeal to heavy land growers.