Easy to exploit great flexibility of red clover…
Clover can play an important
part in lowering production
costs on livestock units.
Robert Davies reports on
the benefits and needs of
both red an white types
RED clover is a legume increasing in popularity because of its ability to fix atmospheric nitrogen and produce high yields of high protein forage.
KT team leader Raymond Jones, of the Institute of Grassland and Environmental Research, Aberyst-wyth, says it is easier to manage than some other protein rich forage crops and growing red clover imp-roves soil fertility and soil structure.
"It is a flexible crop, providing high quality silage and aftermath for finishing lambs or beef cattle. It is also suitable for conventional and organic systems."
Bloat can be a problem when red clover is grazed, but the risk when feeding red clover silage is negligible, adds Mr Jones. Hungry stock should not be turned into clover-rich fields and special care must be taken on chilly mornings.
Ewe fertility can be reduced when the crop is grazed, so breeding ewes should not have access to red clover for six weeks before and six weeks after tupping. A further concern for producers will be that clover rot and stem eelworm could cause problems if red clover is grown continuously on the same land. A six-year break is advised, when these are found.
When establishing a red clover crop, Mr Jones advises sowing varieties that are more resistant to this disease and pest. He also urges growers to avoid machinery movements between old and new leys.
He suggests several options for successful establishment – direct seeding followed by rolling, tine harrowing then broadcasting into an existing sward, or broadcasting and rolling. Seed must be sown no deeper than 1.3cm (0.5in) between April and August. Soil should be pH6 and phosphate and potash indexes must be more than 2.
For a mixed sward, the mixture should contain 9.6kg/ha (4kg/acre) of red clover and 19.2kg/ha (8kg/acre) of Italian or hybrid ryegrass. When grown under barley, the amount of grass seed can be reduced by 2.4kg/ha (1kg/acre). This method of establishment reduces weed problems, but for best results the cereal should be conserved as arable silage before full maturity, says Mr Jones.
A red clover/rye grass sward will fix 120-150kg of nitrogen/ha/ year (96-120 units/acre). The P and K removed as conserved crop must be replaced using slurry and bagged fertilisers. The annual requirement is 100-150kg/ha (80-120 units/acre) of phosphate and 250-300kg/ha (200-240 units/acre) of potash.
In year one, a red clover/ryegrass ley will yield about 13t of dry matter/ha (5.3t/acre). Average yield will decline over the anticipated three production seasons, but should still be about 10t DM/ha (4t/acre) in the third.
"A red clover, perennial ryegrass and white clover combination will produce excellent yields of high quality silage over three years and another two or three years of grazing and conservation cuts."
Mr Jones says red clover is best suited for silage. "Up to four cuts a year can be taken, but there needs to be a 6-8 week interval between mowings."
However, he warns that excess wilting after mowing leads to leaf shatter, high field losses and lower feed quality. The cut crop should be handled with care, using rubber tines when possible, and the silage should come in at 25 to 35% dry matter.
Because red clover silage has low soluble carbohydrate content and a high buffering capacity, he advocates using an inoculant additive to ensure good fermentation.
Silage quality should be good with a metabolisable energy content of 9.8-11.3 MJ/kg DM, 14-19% crude protein and a pH of 4-4.5. On average there will be less than 5% ammonia nitrogen in the total nitrogen content.
However, he warns that red clover is a short-term crop and to maximise its persistence sheep should not graze it over winter.
• Establish April to August.
• High yield in first year.
• Take silage in four cuts.