GRAZING SHEEP AND CATTLE TOGETHER OR SEPARATELY - EFFECT ON SOILS ANDPLANTS

Differences in gazing behavior suggest opportunities to improve forage use when cattle and sheep graze in the same pasture, but a better und erstanding of their effect on soils and plants is needed. Angus cows ( Bos taurus) with calves and ewes (Ovis aries) (1/2 Dorset, 1/4 Finn, 1 /4 Rambouillet crossbred) with lambs grazed Kentucky bluegrass-white c lover (Pea pratensis L.-Trifolium repens L.) pastures from spring unti l autumn in a study of the effects on soils and plants of grazing catt le and sheep together and separately. The experiment was a randomized block design with three replications conducted during 3 yr. There were 6 cow-calf pairs per replication of cattle alone and 6 ewes with 11 l ambs per replication of sheep alone. For the mixed-grazed pastures, th ere were 6 cows plus 6 ewes, each with their respective offspring, per replication. Grazing sheep alone increased soil bulk density (1.47 vs . 1.38 g cm(-3)), extractable soil P (140 vs. 80 kg ha(-1)), and perce ntage bluegrass (36 vs. 25%), but decreased percentage white clover (3 vs. 10%) compared with grazing cattle alone. Grazing sheep and cattle together resulted in soil bulk density and extractable soil P of 1.45 g cm(-3) and 115 kg ha(-1), respectively, Grazing sheep and cattle to gether resulted in a higher B horizon soil pH (6.7 vs. 6.4 and 6.5) an d percentage organic mater (1.9 vs. 1.5 and 1.7) than where cattle or sheep gazed alone, respectively. Percentage bluegrass and white clover present in the sward where both animal species grazed was 37 and 5%, and there were fewer forbs (12%; P < 0.08) than when cattle or sheep g razed alone (18 and 15%, respectively). Grazing both animal species to gether appeared to have beneficial effects on several botanical compos ition and soil characteristics over grazing cattle and sheep in separa te pastures.