Conventional farming can make you lazy – if a field isn’t growing well, you can just throw more fertiliser at it.

And Stephen Colwill was no different.

“But I am now a complete convert – I’ve been converted to organic as much as my farm has.”

He keeps 74 ewes and 30 British Holstein dairy cows at New House Farm, Launceston, Cornwall and rears all his calves to 15-18 months old.

The 61ha (150 acre) tenanted farm finished organic conversion in 2001 and grass yields have now recovered to pre-conversion levels, he says.

“And the land is in much better heart that it was when I was conventional farming.”

Mr Colwill has 28ha (70 acres) of permanent pasture; 3ha (7.4 acres) of forage peas mixed with oats; 10ha (25 acres) of spring oats and winter triticale; and 19ha (47 acres) of red and white clover leys with grass.

“I try to be as self-sufficient as I can.”

The red clover leys are sown at a rate of 7.4kg/ha (3kg/acre) of Milvus red clover to 22kg/ha (9kg/acre) of late perennial ryegrass.

Mr Colwill takes two to three cuts of silage from the leys, which last about three years.

These are followed by one or two years of oats or triticale, and one year of whole-crop peas with oats.

“I quite often use stubble turnips before the peas to give some green cover over the winter.

Then I undersow peas with a white clover and grass mix in April – I find it the best way to get it established.”

The white clover is sown at a rate of 2.5kg/ha (1kg/acre), with 1.5kg/ha (0.6kg/acre) of red clover, 3.7kg/ha (1.5kg/acre) of Timothy and 25kg/ha (10kg/acre) of ryegrass varieties, sometimes with the addition of 2.5ka/ha (1kg/ha) of herbs.

Leys usually last six or seven years, and more distant fields are cut once a year for hay, with in-bye pastures cut twice a year for silage.

“I’ve been pleasantly surprised by our yields.

I’m getting as much silage now as when I was conventional, although arable yields are lower.

Livestock also prefer the natural pasture – before they grazed around the hedges, but now they graze fields much more evenly.”

Mr Colwill has had problems with low fertility in ewes grazing red clover at tupping time, but has not struggled with bloat in the cattle.

The key is not to allow them onto clover with empty stomachs, he says.

“I strip graze the leys in the daytime and put cattle onto permanent pasture at night to give them a break.”

Potash, not nitrogen supply, is the farm’s biggest problem, particularly in cutting leys.

But lime costs have fallen since Mr Colwill stopped applying ammonium nitrate.

Micro-nutrient levels also appear to be higher, he adds.

“Grass seems to be of better quality – we are getting better results from our organic silage than we did with the conventional cuts.”

Milk yields are now about 6000 litres a cow – just 500 litres down on the conventional levels.

Slurry from cows is put through a weeping wall, and the resulting dirty water pumped onto fields, leaving the solid muck to be composted and spread throughout winter, weather permitting.

“You can’t leave it all until the spring because of milk taint.”

olivia.cooper@rbi.co.uk