Reseeding grass leys is an important job for many farmers, but the behind-the-scenes work that goes into growing a quality crop of herbage is often overlooked.

For Lincolnshire farmer Andrew Stovin, who farms in partnership with his father, Alan, and brother, Matthew, herbage has been part of the arable rotation for more than 60 years and now represents a significant proportion of the farm’s income.

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Seed purity and minimal seed loss are essential for a profitable crop.

The deep-rooting nature of grass helps build organic matter and alleviates compaction. Herbage offers a higher gross margin than winter wheat and provides opportunity for livestock integration.

“Herbage is very versatile. We essentially get three products and incomes from just one crop. These are: seed, sheep grazing and hay for the farm’s 60-cow suckler herd,” explains Mr Stovin.

He gives an insight into the process of seed production and explains why a simple switch to a Shelbourne Reynolds stripper header and investment in a seed cleaning plant has saved the business both time and money. 

Establishment

Herbage production begins by direct-drilling a two-year grass ley into winter wheat stubble in mid-September, set for a two-year harvest.

A total of 160ha of grass seed is grown at NM Stovin Farms, located between Louth and Alford on the Lincolnshire coast. Grass is grown on contract for Germinal and Barenbrug, and is composed of the following types:

• Amenity Slow-growing, lower-yielding varieties bred for football/rugby pitches, lawns and golf courses. One-third of this is grown across 160ha.
• Diploid agricultural Mainstream varieties with two sets of chromosomes per cell; 14 in total. Diploids provide a denser crop with more tillers per plant and more seeds per kilogram.
• Tetraploid agricultural Faster-growing grass with a higher sugar content and four sets of chromosomes per cell; 28 in total. The higher cell content leads to improved digestibility and utilisation by livestock.

Optimising yields

Mr Stovin uses a low seed rate of 8-10kg/ha to maximise the amount of light reaching the sward to promote yield.

As grass seeds are sensitive to drilling depth, he aims for a 15mm seed placement. A recent switch from a Vaderstad Rapid drill to a Horizon DSX has improved seed placement accuracy.

Yields range between 1.2-2.2t/ha depending on variety and whether it is in its first or second year of harvest.

Crops tend to be slightly lower yielding in their second year due to seedling volunteers, which is why grass leys are only kept for two harvests.

“Seedling volunteers are a significant barrier to yield. We always get a percentage loss out the back of the combine, which increases the density of the sward and reduces yield year-on-year.”

Grazing a neighbour’s flock of sheep between the first and second harvest helps minimise volunteer establishment, while also cycling nutrients and creating additional income.

Sward management

Managing a herbage sward differs from other seed crops. The aim is to develop a strong, upright canopy throughout the growing season, with a lodged crop at harvest. 

A flat mat of lodged grass reduces potential seed loss by sheltering the crop from the elements.

“Lodged grass forms a carpet that collects any dropped seed, which the combine can harvest rather than being wasted,” explains Mr Stovin.

Grass is a very fragile crop, and is susceptible to significant yield losses when struck by rain and wind.

A good plant growth regulator programme (PGR) is therefore key to avoiding early lodging to maximise light absorption during grain fill and keep disease pressure down.

“We usually apply one or two sprays of growth regulator, but this is very much dependent on how ‘growy’ the season is. In last year’s drought we only used PGRs across one-fifth of the area,” he says.

Growing a range of varieties with different heading dates, from early to late, helps avoid the grass maturing at once and reduces risk of seed loss.

Stripper header harvest

Rather than taking a direct cut with the farm’s conventional header, Mr Stovin switched to a specific grass seed stripper header manufactured by Shelbourne Reynolds five years ago. This cuts the grass ear off at the top of the stem and leaves the stem standing.

Cutting at 6-10kph, this more than doubled harvest output/day and came with a significant fuel saving as it eliminated the need to harvest the entire crop.

“The stripper header is quicker and cheaper to run, as we are no longer combining the entire crop. It is also more effective at hoovering up any potential seed losses.

“The beauty of the stripper header is that in catchy seasons we can take the crop off slightly greener – as high as 30% – and then dry down to below 14%,” he says.

Mr Stovin notes seed crops must be dried at a cool temperature to avoid negative effects on germination. “That’s why we store grass seeds in a 2-3ft-deep pile on a drive-on floor store,” he says.

After the seed has been harvested, the remaining grass stalks are either mowed for hay-making or mulched with a flail topper to return organic matter to the soil.

The crop fits well into the rotation, which is typically followed by two crops of winter wheat, then spring beans or spring barley.

“It’s a necessary requirement to have a one-year gap between planting new grass leys and a four-year gap when changing varieties.”

He also notes that second wheats are often higher yielding than first wheats due to organic matter breakdown in the soil.