Smarter grassland management is needed, writes Dave Roberts
Grass can be used on sports fields or pastures, grows from sea level to mountain top, tolerates drought or flood and temperatures from sub zero to baking. It gets little of the recognition it deserves, yet Scotland is a country far more able to grow grass than many alternative crops and grassland covers over two thirds of a third of the country.
On Wednesday 18 May, Scotland’s Rural College (SRUC), on its Crichton Royal Farms in Dumfries, will host Scotgrass, an industry wide event focused on the growing, harvesting and conservation of grass for feeding livestock. However any display of glossy machines and the advice and research on show represents only part of the grass story.
Much of our grassland was once woodland, cleared for settlement and kept tree-free by farming and grazing pressure as numbers of cattle, sheep and even deer grew. Bar the narrow east coast strip from Caithness, through Angus and Tayside to the Lothians and Borders, Scotland’s climate, soil types and topography offer few opportunities for growing alternative crops.
Of the 82 per cent of Scotland’s agricultural area that is grassland only a third is intensively managed and sown with specific species or varieties. It is the dairy, beef and sheep farmers from those lowland areas who will visit Scotgrass seeking better, more efficient ways of utilising this home-grown crop.
Most grass growth in Scotland is at its maximum in May before, progressively, losing vigour and nutritional quality through the summer and autumn. The management challenge is to extend the growing season and maintain grazing quality as long as possible, conserving the surplus for the five months or longer stock will be indoors.
Wetter summers rule out sun drying grass for hay. More practical is chopping and packing it in clamps or plastic bales where, in the absence of air, it pickles, ready for use as a supplementary feed or basic winter ration. Sophisticated machines for greater harvesting throughputs, or with GPS technology to minimise fertiliser wastage will be on show at Dumfries.
These are not options outside the lowlands. Growing good grass in the less favoured, rugged uplands or islands relies more on people managing grazing herds or flocks than machinery. A shorter growing season and less productive grass species offer few opportunities for saving winter feed.
But such upland grasslands are also recognised for their diversity of species. Many of the valued herbs and wildflowers they support cannot survive the fertility of the lowland pastures and along with them come insects and other wildlife.
However animals like sheep or cattle, with rumen stomachs to help digest grass, produce methane, a greenhouse gas and major contributor to climate change. Also contributing are animal manures or other fertilisers used to boost grass yields.
But Scotland’s imbalance in land types means addressing climate change is not so simple. A simple switch to more plant-based human diets cannot be achieved without increased imports and we need some level of grazing to maintain those valued habitats and landscapes. Our knowledge about how to manage grass and grazing to reduce impacts on climate change is increasing. With so few opportunities to replace our grassland, managing it smarter is the key priority.
• Professor Dave Roberts is head of SRUC’s dairy research centre