Stuart Evans: Undersowing yields sustainable production benefits 

Facing the challenge of controlling inputs and reducing weed burdens as an organic dairy farmer, Stuart Evans has responded by undersowing grass and clover with arable crops. Find out how this productive system works. 

Farming 105 hectares across two units in Carmarthenshire, he moved to Lan Farm, Meidrim, in 2019 on a Farm Business Tenancy (FBT). He previously milked cows on a tenanted farm near Fishguard for 10 years. 

Now situated closer to his father, Haydn’s home farm of Parceithin, Stuart can rear youngstock there. This enabled him to increase his herd of British Friesians from 80 to 115, alongside 60 followers. 

Organic challenges

The farm is producing 3,648 litres of organic milk from forage, accounting for 60% of total production, and supplying the consumer dairy brand Rachel’s Organic. 

The Evans family have been under organic stewardship for over 30 years, meaning they can’t use glyphosate or pesticides. This has driven them to refine their crop rotations over time to remain profitable while mitigating risk from weeds, diseases, and pests. 

Soil first

Stuart believes good soil health is the foundation for healthy crops. Soil samples are taken annually, and he keeps meticulous records, measuring grass growth weekly and recording the results.  

“We do basic soil sampling and address any issues with lime. Farmyard manure and slurry are targeted to silage fields to replace lost P&K,” he explains. 

As artificial fertiliser can’t be used, Stuart says using clover is key to naturally fixing nitrogen in leys. While nurturing soil health, clover also supports production and is integral to his reseeding strategy. 

Reseeding for quality yield 

Approximately 15% of the farm is reseeded annually. Five-year grass and clover leys are undersown with arable silage and a brassica break crop is used to reduce weed and pest burdens.  

“You must have a five-year break following red clover because there’s a high risk of clover rot (sclerotinia trifoliorum) and stem eel worm (Nematoda) parasitic strain. Sclerotinia is a soil-borne fungal pathogen which can reduce productivity,” explains Paul Morgan from Germinal.  

Crops are inspected for diseases, but Stuart says none have been observed yet, which he attributes to the long break between crops. 

Stuart used stubble turnips before, but in 2024 sowed Redstart, a hybrid brassica combining kale and forage rape, that produced a good grazing yield. 

Grass fields are ploughed, power-harrowed and brassica seed is broadcast at 5kg/ha in August. The field will be ploughed again in spring, and five-year grass and red or white clover leys will be undersown with an arable mix of peas and oats.  

“We drill the arable silage and then broadcast grass seed over the top,” explains Stuart. 

The arable silage crop acts as a nurse crop, helping the grass establish with less competition from weeds. It’s then cut eight weeks after sowing and layered into the clamp alongside grass silage. “Cutting the silage early allows sunlight to reach the grass, helping it grow”, explains Paul. 

With one-third of the farm now reseeded, he hopes that as more land is reseeded, overall grass yields will rise from 6t/acre to 10t.  

Germinal forage lifts production 

When reseeding in May 2024, Stuart used an organic forage seed mixture combining Germinal’s Aber High Sugar Grasses and AberPasture white clover. 

First grazed in August 2024, a 2025 measurement has since shown that the paddock outgrew the others by 1.2t DM/ha from February until the end of April. 

“Growth has been phenomenal,” says Stuart. “It has grown 29.1kg dry matter per hectare per day on average since February, despite the slow start we have had to spring, and it is very palatable. 

“Butterfat increased 0.21% and protein 0.13% when cows grazed the reseeded fields,” he adds, explaining this equates to an increase of 175kg of milk solids monthly. The overall yield is around 6,000 litres at 4.1% butterfat and 3.2% protein. 

In 2025, Stuart has since sown an organic red clover silage mixture from Germinal. This contains AberClaret, a longer-lasting red clover that can persist for up to five years. He aims to take three to four cuts per year from silage leys, with the last one baled. 

“We have been using clover for thirty years. Red clover offers high production value and adds protein to the cows’ diet, helping us to reduce the amount of concentrate we feed. Cows are currently fed around 1.2t of cake annually,” Stuart explains.   

Feeding system 

Split block calving begins on 15th February and runs for nine weeks, while another 70 animals calve over 12 weeks from 15th August.  

Cows are turned out to graze in February while calving. They are strip-grazed and typically enter covers of 2,900kg dry matter/ha and exit paddocks when residuals hit 1,600kg DM/ha.  

The herd remains outside until September, when they are housed at night. In October, milkers transition onto brassicas by day, weather depending. 

“We feed bales when the cows are out by day and housed at night and save the clamp for later in the season.” 

Once fully housed, they receive grass silage, peas, and oats, ensiled in layers in the clamp. This is fed in a ‘cut and carry’ system using a skid steer and sheer grab to keep machinery costs minimal.  

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