The influence on summer-rested veld of grazing during autumn, winter, and early summer was studied in Cymbopogon-Themeda Veld at Potchefstroom. Continuous grazing throughout the winter period, and even during early summer, severely damaged species such as Themeda triandra, Eragrostis curvula and Digitaria eriantha although it did not affect total herbage yields. Early summer grazing stimulated undesirable species such as Elyonorus argenteus. A sound system of rotational grazing could, however, avoid damgae of desirable grass species, while keeping unwanted species in check. UITTREKSEL Die invloed van beweiding gedurende die herfs, winter en vroeë somer is opCymbopogonThemeda-veld te Potchefstroom bepaal Die algemene praktyk om veld aanhoudend gedurende die hele winter en selfs vroeë somer te bewei het skade aan soorte soos Themeda triandra, Eragrostis curvula en Digitaria eriantha veroorsaak, alhoewel dit nie die totale opbrengs beïnvloed het nie. Vroeë somerbeweiding kan ongewenste soorte soos Elyonurus argenteus stimuleer. 'n Goeie wisselweidingstelsel kan egter skade aan goeie grassoorte voorkom en tog ongewenste soorte in bedwang hou.

An optical method for measuring canopy-spread cover of shrubs is described by means of an illustrated example. Boundaries of plots are hypothetical lines joining the centres of wholly visible shrubs or groups of shrubs surrounding the observation point. Plots are subdivided into triangular subplots to allow calculation of plot size as well as the percentage canopy-spread cover inside plots. A listing of a FORTRAN programme for the calculations can be supplied. UITTREKSEL'n Optiese opnamemetode vir die raming van kroonregimebedekking is bespreek met behulp van 'n ge'illustreerde voorbeeld. Perseelgrense is die denkbeeldige verbindingslyne tussen die midddpunte van volledig sigbaie struike of groepe struike rondom die waarnemingspunt. Vir die berekening van perseelgroottes asook persentasie ki'oonregimebedekking binne persele, is persele in di'ichoekige subpersele opgedeel. 'n FORT RAN -program vir berekenings kan voorsien word. INTRODUCTIONDifficulties often arise in studying the vegetative cover of shrubveld, particularly in the work of pasture scientists. Their interest is in those parts of the plant which are within easy reach of browsers. Changes in the availability of browse are important, because shrubs often provide the greatest part of the animal diet.Survey techniques for measuring canopy cover, such as the variable plot method of Cooper (1957), arc not primarily designed for measurements at a fixed height. The modified wheelpoint technique of Von Broembsen (1965) is not practicable if the shrubs are impenetrable; besides, it measures only basal cover. The descending-point method of Roux (1963) is suited only to shrubs of 0,7 m or less in height. For these reasons an attempt was made to develop an optical technique more adaptable to the needs of pasture workers.The aim was a method which could easily be applied. Measurements were to be limited to angular and distance readings. The topographic-tacheometric telemeter "Telelop", manufactured by Zeiss Jena, was found suitable for this purpose.

No abstract

Data processing can be time-consuming when experiments with advanced designs are employed. This, coupled with a shortage of research workers, necessitates automation. It is suggested that with automation the first step is to determine how the data must be analysed. The second step is to determine what programmes are available. If a programme is not available it will be necessary to write a new programme. An example of research work where both animal and botanical data are analysed, is given. UITTREKSELDataverwerking kan baie tydrowend wees as proefwerk met gevorderde uitleg uit evoer word. Dit gekoppel met 'n tekort aan navorsers noodsaak outomatisasie. Dit word voorgestel dat met outoma isasie die eerste stap is om vas te stel hoe die data ontleed moet word. Die tweede stap is om vas te stel welke programme beskikbaar is. As geen program beskikbaar is nie, sal dit nodig wees om 'n nuwe een te skrywe. 'n Voorbeeld van navorsing waar beide dierlike en plantkundige data ontleed word, word gegee.