Soaring nitrogen prices are encouraging livestock producers to consider ‘alternative’ sources such as white clover, reports Barenbrug UK.
With UK-produced ammonium nitrate nudging £297/tonne in AHDB’s fertiliser price series – an increase of nearly 50 per cent on the year, taking it to its highest price point for seven years – clover’s in-built nitrogen- fixing ability has prompted more and more farmers to consider including the legume in late-summer overseeds, or autumn reseeds.
“White clover will fix up to 150kg/ha per annum, depending on soil and climatic conditions,” says Mhairi Dawson, Barenbrug’s R&D manager, “which can unshackle producers from their reliance on artificial nitrogen.
“And clover itself is higher in protein than grass alone, typically providing a crude protein (CP) content of 27 per cent. Every 10 per cent increase in the amount of clover in the sward translates into a 1 per cent CP increase in first-cut silage.”
Ms Dawson says that some livestock enterprises are now relying on white clover alone for their grassland nitrogen requirements. “There’s no decline in productivity, yet they’re still getting the environmental benefit and the vastly lower costs. Research has shown that the white clover/grass combination produces more dry matter than grass alone. Couple that with improved digestibility – typically clover has a D value of more than 75 per cent – and the result is more meat and milk from the same area.”
White clover also improves grassland resilience during times of stress, emphasises Ms Dawson, such as during drought, flooding or periods of high disease pressure. In wet, late springs or early autumns that prevent travel and the application of artificial nitrogen, clover can provide grass with atmospheric nitrogen instead, allowing it to continue growing.
For those looking to overseed, rather than include clover in a reseeding mixture, Ms Dawson recommends a maximum of 2.5kg/ha. “White clover supplies around 1.5m seeds per kilogram, so a little goes a long way.
“Its versatility in seeding is another attraction,” she points out. “Apply it with slurry or dung, spin it out from a spreader or even feed it through sheep by adding to a lick bucket or a molassed feed. By adding it while stock remain in the field, it will be pressed in by their hooves.”
Variety choice depends on cutting and grazing requirements, with small-leaved varieties best for heavy sheep grazing and the very largest best for silage.