The growth of white clover (Trifolium repens) in five sown hill swards grazed by sheep.
Abstract
Growth of Trifolium repens was studied in 5 hill swards in Wales, sown 10-39 years before with seed mixtures containing T. repens and Lolium perenne and grazed by sheep. An increase in T. repens ground cover between Feb. and June was mostly due to a near-fourfold increase in leaflet size. The peak period for leaflet size was around 21 June. Plants appeared vulnerable to defoliation in early spring, with leaves very close together on the stolon and a lack of branch production. The smallest differences between the 5 study areas were in rate of leaf emergence and leaflet size and the biggest differences were in the amount of branch stolon extension. More leaves emerged on branches than on the stolon main axis during June, July and Aug., except on 1 study area where branching appeared to be inhibited by Agrostis tenuis [A. capillaris], acidity and Al. Branch production and growth from recorded nodes were greatest where T. repens ground cover was increasing from a relatively low level. The rate of stolon extension appeared sensitive to moisture supply. Management to encourage vigorous growth, therefore, would include providing both sufficient lime and sufficient moisture, controlling Agrostis, and avoiding both overgrazing in spring and undergrazing in summer.