Red clover adds protein boost to growing sward
Managing grass swards for
improved protein content,
higher yields and lower
nitrogen losses were key
topics at Grassland 99.
Jessica Buss and
Emma Penny reports
OVER-SEEDING red clover into grass swards, using minimum cultivation techniques after first cut silage, can lift the protein levels in the sward and allow a second silage cut, but success may be weather dependent.
At Grassland 99, held at Stoneleigh, Warks, IGER Aberystwyth researcher Rhun Fychan said one difficulty with increasing the protein in forages is getting red clover into existing swards. But including red clover in a grass sward will increase total crop yield, silage protein content and save nitrogen fertiliser.
He offered three options for establishing clover which allow a grass sward to stay in production for a second silage cut, and which cost less than ploughing and reseeding. These include broadcasting seed, using a tine harrow to create a tilth and direct drilling.
These are being trialed with MAFF and MDC funding, but the best option may vary according to the farm situation, he added.
Mr Fychan recommended over-seeding after first cut silage, when the sward was open. "Red clover seedlings should emerge and establish before the grass takes off, but they will need some moisture."
Broadcasting seed on the surface and rolling it in was the cheapest option, but also the riskiest because seed would not germinate in dry weather, he said. This method costs about £112/ha (£45/acre), including 5kg/ha (2kg/acre) of seed at £25/ha (£10/acre), slug pellets at £12/ha (£5/acre) and P and K fertiliser.
"Using a tine harrow to pass over the sward two or three times produces a fine tilth, and can be done while the sward is open after first cut silage. But it needs some moisture to establish, so the weather is crucial," said Mr Fychan. He calculated that tine harrowing before sowing seed costs £127/ha (£51/acre).
The most expensive option, including machinery and materials, at £132/ha (£53/acre), is direct drilling into an existing sward. "This is not so weather dependent and can result in strong, fast emergence. But it tends to need a contractors machine, similar to one used for cereals," he added.
But Arthur Davies of IGERs Bronydd Mawr research station, Powys, warned that incorporating red clover into existing swards after first cut is risky. He believed red clover should be sown in a spring reseed during moist conditions.
• Over-seeding may succeed.
• Three possible options.
• Seeds need moisture.