Experimental comparison of the nature conservation value, productivity and ease of management of a conventional and a more species-rich grass ley.
Abstract
A large-scale field experiment near Oxford, England, was used to evaluate two contrasting grass leys in terms of nature conservation value, productivity and ease of management. The leys were suitable either for green cover on land removed from arable production (as part of Set-Aside or similar schemes) or for low-input agriculture or amenity uses. One ley was a conventional mixture of cultivars of Phleum pratense (timothy), Lolium perenne (ryegrass) and Trifolium repens (white clover). The other was a more species-rich mixture, based on 19th century 'herbal' leys. It comprised six indigenous grasses and three forbs and excluded L. perenne and T. repens. The leys were managed both as hay and silage and were grown both with and without the appropriate fertilizer applications. Over a three-year period the more species-rich ley retained more sown species and accommodated more naturally regenerating species than the conventional ley. Loss of sown species increased at high fertilizer levels. Numbers of both sown and naturally regenerating species were lower under the silage than the hay cutting regime. These results are discussed in relation to the relative dominance of sown species. The more species-rich ley was also less productive and consequently easier to manage by infrequent mowing. It is concluded that carefully selected but simple mixtures of indigenous grasses and forbs are likely to satisfy a diverse range of management requirements, whilst at the same time benefiting wildlife and visual amenity in the wider countryside.