13 August 1999

Clover leys build soil fertility

CLOVER is the engine powering one May lambing flocks rotational grazing policy as it enters organic conversion.

Farm manager Charles Mclean told visitors at the Signet/SAC May lambing open day at Sheep-drove Organic Farm, that the 1400 Mule and Masham ewe flock needs clover and grass.

"Its the roast beef and Yorkshire pudding of the whole system. Grass leys are part of whole farm rotation, while white and red clover leys are used to build soil fertility and break weed cycles."

A total of 137ha (340 acres) at Sheepdrove are organic, while a further 404ha (1000 acres) are in conversion and the balance, 207ha (511 acres), will be put into conversion next year.

Despite not being enthusiastic about converting to organic farming initially, Mr Mclean cannot wait to become fully organic. "We are in a half-way house situation and that is difficult to manage."

Whether its part of an organic system or not, Mr Mclean realises clovers potential for improving lamb production. But it can cause problems which he didnt have when producing lamb conventionally.

"Ewes and cows can become overfat, which means there are fertility concerns." Condition needs to be monitored up to tupping as a result, but lambs grow rapidly, he added.

White and red clover leys are split across the 364ha (900 acres) of grassland, with one-third of leys being red clover, grown for forage. White clover leys are grown for four to five years on the remaining area to break weed cycles in arable crops and replace fertility.

The normal rotation across the farm is one year winter wheat, one year spring wheat followed by white or red grass clover leys undersown into wheat in March.

"We aim to undersow in the second week in March, when wheat is at third leaf growth stage. May is definitely too late for this."

Mr Mclean said this establishment technique is sometimes too successful, causing harvesting problems. "We set the header 6in below the wheat ear, otherwise the combines sieves become full of green material." Stubble is knocked down by grazing cattle or using a flat roller, he added.

With 140 suckler cows sharing grazing, Mr Mclean rotates grazing annually between cattle and sheep to keep pasture parasite free. The aim is for ewes to lamb in May on clean pasture, so lambs grow unchallenged. &#42