J.O. Grunow

Feed and habitat preferences among some large herbivores on African veld

Abstract 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 se...

Long term nitrogen application to veld in South Africa

Abstract The most important results of thirteen fertilizer experiments on veld, extending over periods of five to twenty years, are dealt with. In general, with nitrogen fertilization climax grasses were replaced by grasses of a more pioneer type. Of the nitrogenous fertilizers used, ammonium sulphate maintained the best basal cover (urea not considered) and produced the greatest yield response (urea included) . Compared with ammonium nitrate, sodium nitrate and urea, it also displaced the climax grasses most rapidly, whilst urea had the slowest displacement effect. Above approximately 150 lb N per morgen p.a., urea gave the lowest hay yield on veld, but this might not have great economic implications. Strong and fairly consistent correlations were observed between summer rainfall (October to Match) and air‐dry herbage yield, and better yields were obtained in dry years with adequate fertilization than in wet years without fertilization. The response of veld to N‐fertilization in terms of crude protein pr...

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

Abstract 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 digestible 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.

Production and quality norms of certain grass species for fodder flow planning: Pretoria area

Abstract Four subtropical (Cenchrus. Digitaria, Anthephora and Sorghum) and two temperate grass species (Festuca. Agrotricum) were grown in a replicated field experiment at three levels of N application, with adequate P and K. Species were mown at 4‐, 6‐ and 8‐weekly intervals. DM production data for 6‐ and 8‐weekly and 4‐ and 6‐weekly intervals are presented for subtropicals and temperates, respectively. The object was to determine the seasonal accumulative DM production curves, productivity spread and quality, for use in fodder flow planning. The subtropical grasses produced 2 to 3 times as much DM as the temperate grasses : CGR 745—1237 versus 345—440 kg/ha/wk under supplementary irrigation. The subtropicals produced ca 2{h times as much under irrigation than under rainfed conditions. Festuca and Agrotricum, Digitaria. Athephora and Sorghum, Cenchrus, gave peak CGRs after 9, 15, 16 and 18 weeks after end of August, respectively. Irrigation resulted in peak CGR being reached earlier in the growing seas...

The effect of fire, with and without subsequent defoliation, on the herbaceous layer of Burkea Africana savanna 1

Abstract 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 undipped plots. In a similar comparison, the rate of accumulation of forage species biomass was, h...

A comparison of highveld fodders and fodder flows for growing out long yearling steers.

Abstract A fodder flow/animal experiment 40,8 ha in extent (7,5 ha irrigated), with 19 paddocks, was carried out over a two and a half year period. The aims were: firstly, to compare fodder crops within seasons, and fodder flows over three seasons (winter‐spring‐summer), by means of pasture and animal parameters; secondly, to make economic comparisons between different fodder flows, for growing out beef steers. The conclusions were that: Digitaria eriantha ssp. eriantha is superior to Eragrostis curvula cv. Ermelo for animal production; maize residue gives economically favourable results due to low costs and compensatory growth of cattle; an irrigated pasture providing fodder in more than one season of a flow, for example, Festuca foggage — Festuca pasture — Digitaria pasture, gives a very profitable fodder flow, because the costs of production are divided between two seasons; dryland fodder flows with the sequence maize residue — silage or hay — Digitaria or, with silage or hay replacing the maize residu...

Standing crop dry matter accumulation and quality patterns of certain subtropical pasture species

Abstract Nine‐week production curves and quality values of eight subtropical pasture species were studied under supplemental spray irrigation to characterize their productive capacity, periodicity and quality. All species exhibited a slow dry matter regrowth rate for two to three weeks after defoliation to 7,5 or 10 cm height. Thereafter, there was an ever increasing rate of production up to nine weeks with the exception of certain species in certain seasons, which reached the point of inflection in production rate after a shorter regrowth period. When dry matter accummulation is most rapid, quality is unsatisfactory. Bushman Mine and Sabi panicums gave their highest dry matter production in the late season; Pennisetum clandestinum, Eragrostis curvula and Anthephora pubescens in the early season; whereas, Cenchrus ciliaris, Cynodon nlemfuensis and Medicago sativa differed little in early and late season. All species lost quality fairly suddenly, or steadily, after 4,5 to 6 weeks regrowth without moisture ...

Preference rating and other characteristics of a few promising eragrstos curvula ecotypes as determined by grazing sheep

Abstract Eragrostis curvula cv. Ermelo, as control, was tested against several ecotypes at two localities in the Transvaal Highveld in respect of dry matter yield, percentage utilization, preference rating and herbage quality, using sheep mainly, as tester animals. The ecotypes were: Ermelo 228, Morpa 222, Tanganyika 192, Renner 274, Rietspruit 267, Thabamhlope 175, Makwassie 150, Pearston 204, and Cape Province 5. Makwassie 150 showed up well in regard to preference rating, herbage quality and percentage utilization, but lost a little on dry matter yield. Cape Province 5 also performed well. Pearston 204, Ermelo 228, and Morpa 222 came next in preference rating and utilization, with Ermelo consistently outyielding the others. Tanganyika, Renner, Rietspruit and Thabamhlope were consistently poor in regard to preference rating and utilization percentage.

Utilization and preference rating of various subtropical pasture species and mixtures

Abstract The percentage utilization and preference demonstrated by Bonsmara beef cows was measured twice (December 1976 and March 1977) on 18 subtropical grasses, legumes andgrass‐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 milanjiana, Panicum maxmum 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 citiaris cv. Molopo, C. ciliaris/Skatro, Vigna vexillata, Macroptilium atropurpureum cv. Siratro, Eragrostis curvula/V. v...

Die evaluering van vier Eragrostis curvula ekotipes met weidende skape

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.