Time to take a slow walk around the Grassland

Making the time to assess grassland quality will be time well spent this spring according to NWF’s Commercial Manager Rupert Stafford.

“2007 was a difficult grass growing year with the wet weather making grassland management a real challenge,” comments Mr Stafford.  “But higher milk prices will mean dairy farmers are keen to make the most of grass again this season, while record fertiliser prices mean they must focus on maximising both yields and quality.”

Mr Stafford believes a great many swards will have suffered from damage as a result of poaching and waterlogging last year.  This will lead to a lower proportion of ryegrasses and a larger population of weed grasses which will have been quick to colonise any space within the sward.

“Weed grasses will reap havoc with both grazing quality and quantity,” explains Mr Stafford.  “A good quality grazed ryegrass sward will produce around 12tDM/ha which will supply enough energy for 24,000 litres of milk over the season.  A sward with only 50% perennial ryegrass, with the remainder being weed grasses will yield upto 2tDM/ha less which is equivalent to enough grass to produce nearly 4000 litres of milk.”

He also stresses that weed grasses are less effective converters of fertiliser into plant material.  A 50:50 ryegrass: weed grass sward will use nitrogen fertiliser 35% less efficiently than a pure ryegrass ley.  He estimates that at today’s prices this will cost around £45/ha in lost potential.

“Taking the time to walk fields as soon as possible to assess the quality of the grasses present will be well worthwhile.  By walking the fields you will get a good idea of the proportion of ryegrass in the leys and can decide on what action to take to get the most from your grass.”

Perennial ryegrass is easily identified as it has a crimson red base. Grasses without this will tend to be less desirable species.

Mr Stafford advises that if there is more ryegrass than weed species, then the pasture will probably respond to harrowing or rolling to remove ruts, followed by usual fertiliser applications.

If the sward is somewhere around 50% ryegrass then consider looking to rejuvenate the sward by slot seeding or overseeding.  A reduced seed rate of around 13kg/ha can be used and at less than £15/ha the cost of the operation is considerably less than a full reseed.

If the sward is less than 50% ryegrass, and certainly if it is below 25%, then a full reseed really is the best option.

“Despite the higher costs associated with a full reseed, there is usually a short pay back period. A vigorous new ley can produce 25% more DM/ha than a tired mixed species ley, allowing the establishment costs to be recovered in the first year.”

Whether rejuvenating or reseeding it is essential to consider the seed mixture to use. Mr Stafford advises farmers select a mix designed for the use to which the field is primarily put and look to use the new high sugar varieties to maximise the kgDM produced per kgN applied.

“Consider using a high proportion of clover in any reseeding mixtures. Fertiliser prices are likely to remain high for the foreseeable future so the benefits of nitrogen-fixing legumes will be even more important.

“Despite higher fertiliser prices however, grazed grass is still a very cost-effective feed provided that all steps are taken to maximise the yield and the response to nitrogen through the maintenance of an optimum sward composition. The starting point for this is the assessment of all grass fields and early decisions about the best strategy for each field,” Mr Stafford concludes.