The role and future of pasture science in South African ecosystems

Ecosystems are increasingly being disturbed and made artificial as the agricultural industry intensifies, urbanisation proceeds and management malpractices degrade the natural vegetation. All man-induced changes are not detrimental, however; in fact, many appear to be advantageous. A holocoenotic ecological view must be taken if grazing and other practices are to be seen in the right perspective in relation to the ecosystem.Item was scanned at 300 dpi. Scanner used HP Scanjet 5590Pp. 11-12: Publikasies van die Universiteit van Pretoria (Nuwe Reeks)http://explore.up.ac.za/record=b106160

Feed and habitat preferences among some large herbivores on African veld.

Impala and springbok are attracted to disturbed areas, while kudu are adaptable to degraded vegetation. Springbok, impala, nyala, warthogs, blue and white-tailed gnu prefer short grass, whereas buffalo, zebra and waterbuck prefer taller grass. Blesbok, white-tailed gnu and sheep are markedly area selective. Blue gnu, zebra, blesbok, sheep, impala, buffalo and white rhinoceri show a decided preference for burnt areas. During winter and dry periods springbok, sheep and white-tailed gnu include more karoo shrub relative to grass in their diets, and impala more savanna trees and shrubs. The diet often consists of 25 to 80 plant species, but only 10 to 20 are preferred and principal forage species. The literature indicates a large degree of overlap in the browse and graze species selected by different domestic and wild herbivores, as well as in habitat preference and feeding height. Browsers select between plant species as markedly as grazers do. Carrying capacity should be determined for different seasons. It is essential to reduce the stocking rate of grazers to account for the amount of common graze eaten by mixed feeders and browsers: similarly, that of browsers to cater for the amount of common browse eaten by the other two feeding groups.Keywords: blesbok; browsers; buffalo; carrying capacity; feeding; feeding behaviour; forage; grass; grazers; habitat; habitat preference; herbivores; impala; karoo; kudu; large herbivores; nyala; savanna; sheep; springbok; stocking rate; warthog; waterbuck; zebr

Utilization and preference rating of various subtropical pasture species and mixtures.

The percentage utilization and preference demonstrated by Bonsmara beef cows was measrued twice (December 1976 and March 1977) on 18 subtropical grasses, legumes and grass-legume mixtures under supplemental spray irrigation. Clipping before and after grazing, with a two to three day period of stay, was carried out on six week old regrowth. Degree of utilization based on a six point scale was recorded twice daily, thereby allowing preference ratings to be related to time and grazing pressure. The following average rating of preference, in descending order, was obtained: Digitaria milanjinana, Panicum maximum cv. Sabi, Medicago sativa, Panicum coloratum cv. Makarikari, P. coloratum cv. Bushman Mine, Sabi Panicum/Glycine wightii, Brachiaria brizantha, Cynodon dactylon cv. Coast Cross I, C. nlemfuensis cv. Estcourt, Pennisetum clandestinum cv. Whittet, Anthephora pubescens, Cenchrus ciliaris cv. Molopo, C. ciliaris/Siratro, Vigna vexilata, Macroptilium atropurpureum cv. Siratro, Eragrostis curvula/V. vexiliata, G. wightii, E. curvula cv. ErmeloKeywords: anthephora pubescens; brachiaria brizantha; cenchrus ciliaris; clipping; cows; cynodon dactylon; cynodon nlemfuensis; digitaria milanjinana; glycine wightii; grasses; grazing; grazing pressure; irrigation; legume; legumes; medicago sativa; panicum coloratum; panicum maximum; pasture; pennisetum clandestinum; percentage utilization; preference; preference rating; regrowth; subtropical grasses; utilization; vigna vexiliat

Groei en produksie van 'n aantal aangeplante weidings onder beweiding.

The growth and production of a number of cultivated pasture species in the grazed condition, were measured by means of the difference method. From the data obtained in the trial it became clear that green material can be supplied right through the year if there is possibility of irrigationLanguage: AfrikaansKeywords: Continuous grazing; Cultivated pastures; Dry-land; Exclosures; Irrigation; Subtropical species; Temperate specie

A comparison of pasture and fodder crops for the production of slaughter lambs in the Pretoria-Witwatersrand-Vereeniging (PWV) area.

A number of pasture and fodder species were evaluated for the production of mutton with weaner lambs. Animal performance and meat production under three stocking rates, which were classified as light, medium, and heavy, were obtained with the aim of identifying best pasture/fodder for every season. The pastures/fodders included were Lolium multiflorum cv. Midmar and Triticum x Secale pastures under irrigation. Avena sativa and Vicia dasycarpa pasture mixture and maize crop residues under rainfed conditions and Medicago sativa and Digitaria eriantha hay for the winter months. The spring pastures were L. multiflorum cv. Midmar, Lolium perenne cv. Nui and Dactylis glomerata cv. Hera under irrigation, while the summer pastures included Digitaria eriantha var. eriantha and M. sativa cv. Cuf 101 pastures under rainfed conditions and Cynodon dactylon cv. NK37 under irrigation. Of these, the Midmar pasture for the winter and spring, maize crop residues for the winter, Hera for the spring and Cuf 101 for the summer seemed to be the best pasture of those tested in their season of use, from an animal production point of view.Keywords: afrikaans; animal performance; animal production; avena sativa; cynodon dactylon; dactylis glomerata; digitaria eriantha; fodder; hay; lambs; lolium multiflorum; lolium perenne; maize; meat production; medicago sativa; pastures; performance; rainfed condition; seasonal production; south africa; stocking rate; stocking rates; university of pretoria; vicia dasycarp

The evaluation of four Eragrostis curvula ecotypes with grazing sheep.

Four ecotypes of Eragrostis curvula, namely, Cape Province 5, Ermelo, Pearston 204 and Makwassie 150 were evaluated in a grazing trial with sheep, at three stocking rates, during two growing seasons. Under conditions of very lenient utilization, where the animals could select freely, the animals on Cape Province 5 had significantly higher mass gains than on any one of the other ecotypes. The sheep on Pearston 204, on the other hand, showed higher live mass gains, although these were not significant, under conditions of more intensive utilization. There were no significant differences in the dry matter production and chemical composition of the clipped samples of the ecotypes.Keywords: afrikaans; chemical composition; dry matter production; ecotypes; eragrostis curvula; grazing; live mass; live mass gains; open rotational grazing system; production; sheep; south africa; stocking rates; university of pretoria; utilizatio

Die benutting van Cynodon aethiopicus clayton et harlan (stergras) en Pennisetum clandestinum hochst ex chiov (kikuyu) as hooigewas vir skape*

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The effect of fire, with and without subsequent defoliation on the herbaceous layer of Burkea africana savanna.

A back-fire applied to the herbaceous layer during September 1978 resulted in significantly less dry matter production over the following year, compared to an unburnt area. This was largely due to the significant reduction in dry matter and basal cover of the non-forage species group which had, prior to the fire, exhibited a notable accumulation of dead material. In contrast, basal cover and dry matter production of the leafier forage species group were not significantly affected by the back-fire. On plots where the burn was followed by an 8-weekly clipping treatment, a slower biomass accumulation rate of the sward as a whole was recorded than on burnt plots allowed unchecked post-fire regrowth. The lowest rate was recorded on unburnt plots allowed unchecked growth. The burn plus 8-weekly clipping reduced the biomass accumulation rate of the non-forage species compared with the same group on unburnt unclipped plots. In a similar comparison, the rate of accumulation of forage species biomass was, however, stimulated by the burn plus 8-weekly clipping.Keywords: basal cover; biomass; burkea africana; clipping; defoliation; dry matter production; effect of fire; fire; herbaceous layer; nylsvley nature reserve; production; regrowth; savanna; south afric

Biomass cycles, accumulation rates and nutritional characteristics of grass layer plants in canopied and uncanopied subhabitats of Burkea savanna.

Annual biomass cycles, accumulation rates and nutritional characteristics of forage and non-forage species groups were determined in the canopied and open, uncanopied subhabitats of the herbaceous layer in Burkea africana savanna. The total amount of biomass of all species over the season was significantly greater in the open than under Burkea africana trees and Ochna pulchra shrubs. However, the amount of biomass and in-vitro diigestible organic matter of forage species was of the same order of magnitude under Burkea africana and in the open, and the amount of crude protein was in fact greater under Burkea africana trees than in the open and under Ochna pulchra in the case of forage species. The amount of biomass, crude protein and in-vitro digestible organic matter of non-forage species was greatest in the open. Biomass accumulation rate of total biomass was greatest in the open, whilst that of forage species was greatest under Burkea africana.Keywords: burkea africana; burkea savanna; crude protein; forage; grasses; herbaceous layer; nylsvley nature reserve; ochna pulchra; organic matter; plants; savanna; shrubs; south africa; subhabitats; tree