Sward dynamics of a smooth‐stalked meadowgrass dominantwhite clover sward rotationally grazed by cattle and/or sheep

Abstract

AbstractThis experiment was carried out to study the responses of sward components (particularly white clover, Trifolium repens) to grazing management in a natural sward dominated by smooth‐stalked meadowgrass (Poa pratensis) syn. Kentucky bluegrass. Treatments during two grazing seasons (1989–90) were: cattle grazing alone (C); cattle grazing followed by topping (CT); cattle grazing followed by sheep grazing (CS); and sheep grazing alone (S). Mean target pre‐ and post‐grazing herbage masses were 2200 and 1100 kg DM ha−1, estimated by single‐probe electronic capacitance meter. Sward component dynamics were monitored using turf dissections, marked white clover stolons, and ring‐toss white clover leaf counts. Component and sward data for the C, CT, CS and S treatments respectively, were: number of white clover leaves m−2, 1295, 1384, 1408, 900 (s.e. ± 108); number of leaves per growing point, 3·2, 3·4, 3·0, 2·8 (s.e. ± 0·2); herbage accumulation (t DM ha−1), 5·16, 5·02, 5·87, 8·28 (s.e. ±0 08); rejected herbage (% pasture area) 39·7, 7·7, 16·0, 0 (s.e. ± 75); and annual net herbage production (t DM ha−1) 3·39, 4·35, 4·99, 8·28 (s.e. ± 0.07). Swards grazed by sheep alone contained less white clover, but regrew quicker and produced more herbage than other treatments. Close topping or grazing by sheep following dairy cattle grazing decreased sward rejection by cattle. These treatments maintained more of the pasture in better condition for subsequent cattle grazing, resulting in greater net herbage production than where no post‐cattle grazing treatment was used.