Silage Advisory Centre

“Estimating the total cost, including labour and machinery, to be around £190/acre, a 7:1 return on investment is a real possibility over the duration of a typical medium term ley. With increased reliance on home produced feed being a key contributor to the increased profitability, renewing an old pasture is a sound investment.

Assuming a milk price of 25p/litre and even a conservative increase in pasture yield and quality, an effective reseed could well be worth £275/year in extra milk from forage in the first year. That’s a handsome return on investment over a period of five years. Higher growth rates and tighter stocking densities are possible with lambs and beef finishers, grazing reseeded pastures, means that similar arguments also apply to the beef and sheep sectors.”

Table:  Typical Reseeding Benefits

“Such results are, however, dependent on reseeding being carried out effectively. To ensure a ‘best practice’ approach, Mole Valley Farmers has developed its Grassland Reseeding Checklist, which identifies a number of key essentials for cost-effective reseeding. This begins with the initial decision of when to reseed and works through the entire process of soil testing, sward destruction, cultivation, sowing, fertiliser and early sward care. 

In the first instance, it’s important to identify the right fields for reseeding, this should be based on ryegrass content rather than the age of the sward. Ryegrasses are easy to distinguish from less productive fescues, bents and meadow grasses, by the pinkish-red tinge to their stem bases. Once they drop to below half the sward content you really need to be thinking about reseeding.

If you want the best possible establishment and the least possible out of production, you should be reseeding in August or early September, allowing the old sward to be kept in the grazing or silage-making system right up to July or early August, if required. Warm soils mean better, more rapid establishment, providing there is sufficient moisture. The new sward then has the winter to develop, with tillering encouraged and frost kill minimised by pre-Christmas sheep grazing, coming into the next season full of heart and productivity.

Effective destruction of the old sward including established perennial weeds is critical to success too. While a simple surface kill may reduce trash, a full rate glyphosate spray is essential to really tackle perennials like docks, thistles, couch, Yorkshire Fog and other weed grasses.

Seedling grasses need a clean start if they are to establish well and dominate the new sward. It can be heartbreaking to see a nice new ley wrecked by couch and other perennials pushing through the seedbed early and out-competing the young ryegrasses.

Use of an effective glyphosate spray will minimise the time taken out of production and maximise reseeding timeliness because it can be applied ahead of the last grazing or silage cut. It is important to allow about 5 days after spraying for the herbicide to penetrate right to the root tips, but then the field can be grazed or cut for silage safely and cultivated immediately afterwards. 

Cultivations should produce a fine and firm seedbed, without delay, to preserve as much soil moisture as possible. If you allow the ground to dry out significantly you could have a disaster before you have started. You will also be on a hiding to nothing if you don’t make sure you get the soil P, K and pH status right. It is well worth having the soil tested and correcting any imbalances. You should also check the ground for compaction and poaching too, and subsoil any suspect or unduly damp areas to improve drainage. Otherwise, you will just encourage weed grasses, rather than the productive ryegrasses you have sown.

When selecting seeds mixtures, livestock farmers should look no further than the official Recommended Lists, and insist on the right blend of ryegrass and clover types.

Mole Valley Farmers Premier Leys are selected from the ‘Recommended’ varieties which give you the assurance of independently tested performance, I always select listed varieties for their combination of yield and other desirable characteristics, like early spring growth, sugar content, ground cover, disease resistance and digestibility, matching them to specific grazing and cutting uses for productive lifespans.
I would also include a decent amount of clover. Research has shown it can increase the productive value of swards by over £70/acre, reduce nitrogen fertiliser requirements and significantly boost July and August grazing in particular.  Some farmers will leave clover out of the mixture initially to allow more effective early weed control and establish the clover later.

Advances in breeding mean there are some excellent new varieties available, most notably the Aber HSG high sugar ryegrasses bred at IBERS, Aberystwyth.  It’s vital not to dilute your mixtures with lesser varieties, best practice means insisting on 100% quality throughout the mixture and varieties that are balanced to achieve a specific objective.”

Recommended medium term ley for milk production (grazing/cutting)

MVF Premier Hi-n-Sile (No 8)

Recommended long term ley for livestock grazing and cutting

MVF Premier Cut-n-Graze

“I recommend shallow drilling, if possible, as grass seeds generally prefer burial, rather than being left on the surface. Broadcasting is perfectly acceptable, providing the seed is harrowed in afterwards. In either case, roll before and after sowing to maximise moisture retention and soil/seed contact.  The seedbed needs to be firm enough to ride your push bike over it without sinking in.

Avoiding seedbed N in most cases, treating the new sward around seedling emergence to minimise frit fly damage as well as using a selective weed killer (clover-safe, if required) to knock seedling weeds on the head as early as possible.

Doing the reseeding job to a ‘best practice’ protocol means using the high quality inputs and applying a high level of care and attention. Over the lifetime of the ley, the extra cost of best practice is negligible compared to the significant production benefits the new pasture will deliver.”