Evaluation of techniques to determine the production potential of cultivated pastures
| dc.contributor.advisor | Snyman, H. A. | |
| dc.contributor.advisor | Botha, P. R. | |
| dc.contributor.author | Vermeulen, Sunet | |
| dc.date.accessioned | 2017-11-01T08:46:55Z | |
| dc.date.available | 2017-11-01T08:46:55Z | |
| dc.date.issued | 2009-12 | |
| dc.description.abstract | English: For farm managers to utilize their pastures more efficiently, it is essential to estimate both herbage biomass and botanical composition. Therefore, there is a need to estimate herbage biomass and botanical composition of cultivated pastures with simple, accurate and cost-effective methods instead of the more accurate, but time-consuming destructive methods. The objective of this study was to evaluate non-destructive methods for estimating herbage biomass and/or botanical composition on different mixed-species pastoral systems for beef and/or dairy cattle and to identify the method, if any, that would be most accurate in each particular pastoral system. A comparison of the rising plate meter, the comparative yield method and the meter stick was conducted to determine the predictability of these non-destructive methods for estimating herbage biomass. Furthermore, the dry-weight-rank method for determining species composition was compared to hand clippings. The accuracy of the different non-destructive methods for estimating herbage biomass was compared using the coefficient of determination (r2) values between cut material and herbage biomass estimates. The study indicated that the meter stick (r2 = 0.79 – 0.85) provided the most accurate values for the dairy pastoral systems. In the beef pastoral systems the rising plate meter (r2 = 0.76 – 0.83) resulted in the most accurate method, for three out of four of pastoral systems. It was clear that species composition of the stand was an important factor affecting the accuracy of herbage biomass estimates. Based on the results of this study, all of the non-destructive herbage biomass estimation methods tested are suitable for use on both farm-level and pasture studies on larger areas. However, in grazing studies that are conducted on relatively small areas and with a relatively small number of animals, these methods may be less accurate and where accurate herbage biomass is desired, cutting is still recommended. Furthermore, the results indicate that the dry-weight-rank method of analysis is an accurate means of determining the botanical composition of both cultivated dairy and beef pastoral systems. The contribution of 92% and 96% of all species within the dairy and beef pastoral systems, respectively, was estimated within 5% accuracy of the “true/actual” value of species determined by hand clipping. These methods for determining herbage biomass and botanical composition can serve as a useful tool to set stocking rates at levels necessary to balance forage supply and demand in pastures that may have uneven species composition. These measurements are essential to make sure that animals are adequately fed and swards not under- or overgrazed and therefore ensure sustainable animal production. | en_ZA |
| dc.description.abstract | Afrikaans: Suksesvolle weidingbestuur vereis dat die beskikbare plantmateriaal vir beweiding en die botaniese samestelling daarvan akkuraat gemeet moet word. Hierdie inligting moet vervolgens doeltreffend in die bestuur verreken word. Daarom bestaan die behoefte om die staande droëmateriaal en botaniese samestelling van aangeplante weidings met eenvoudige, akkurate en koste-effektiewe metodes te bepaal in plaas van die meer akkurate, maar tydrowende kwadraatmetode waar die plante wel gesny word (destruktiewe metode). Die doel met hierdie studie is om verskillende nie-destruktiewe metodes vir die bepaling van staande droëmateriaal en/of botaniese samestelling op verskillende weidingstelsels, bestaande uit gemengde plantspesies, vir vleisbeeste en/of melkbeeste te evalueer en om die metode wat in elke besondere weidingstelsel die akkuraatste sou wees, te identifiseer. ‘n Vergelyking van die skyf-weiveldmeter, ‘n visuele metode en die meterstok is uitgevoer om die voorspelbaarheid van hierdie nie-destruktiewe metodes vir die bepaling van staande droëmateriaal te bepaal. Verder is die droëmassa-rangordemetode vir die bepaling van spesiesamestelling met geoeste (destruktiewe) waardes vergelyk. Die akkuraatheid van die verskillende nie-destruktiewe metodes vir bepaling van staande droëmateriaal is vergelyk deur die bepalingswaarde koëffisiënt (r2) tussen die geoeste materiaal (destruktief) en bepalings deur die verskillende nie-destruktiewe metodes te gebruik. Die studie het aangetoon dat die meterstok (r2 = 0.79 – 0.85) die akkuraatste waardes vir die melkbeesweidingstelsels verskaf. In die vleisbeesweidingstelsels was die skyf-weiveldmeter (r2 = 0.76 – 0.83) vir drie uit vier van die weidingstelsels die akkuraatste metode. Dit was duidelik dat die spesiesamestelling van die verskillende stelsels ook ‘n belangrike faktor mag wees wat die akkuraatheid van die bepalings beïnvloed. Gebaseer op die resultate van hierdie studie, is die getoetste nie-destruktiewe metodes vir die bepaling van staande droëmateriaal geskik vir die gebruik op beide plaasvlak en wetenskaplike weidingstudies op groter oppervlaktes. Inteenstelling waar weidingstudies op relatief klein oppervlaktes en met ‘n relatief klein getal diere uitgevoer word, mag hierdie metodes egter minder akkuraat wees. Waar akkurate bepalings verlang word, word die sny van plantmateriaal steeds aanbeveel. Die resultate toon verder dat die droëmassa-rangordemetode van plantontleding ‘n akkurate metode is om die botaniese samestelling van beide aangeplante melk- en vleisbeesweidingstelsels te kwantifiseer. Die onderskeidelike bydrae van 92% en 96% van alle spesies in die melk- en vleisbeesweidingstelsels is bepaal binne 5% akkuraatheid vanaf die “ware/werklike” spesie voorkoms, soos bepaal met behulp van destruktiewe metode. Samevattend kan verklaar word dat nie-destruktiewe metodes beslis as ‘n bruikbare instrument kan dien vir die doeltreffende bestuur van aangeplante weidings. Hierdie meetings is essensieel vir effektiewe dierevoeding en kan van hulp wees sodat weidings nie onder- of oorbewei word nie en sodoende volhoubare diere produksie sal verseker. | af |
| dc.identifier.uri | http://hdl.handle.net/11660/7373 | |
| dc.language.iso | en | en_ZA |
| dc.publisher | University of the Free State | en_ZA |
| dc.rights.holder | University of the Free State | en_ZA |
| dc.subject | Dry matter | en_ZA |
| dc.subject | Herbage biomass | en_ZA |
| dc.subject | Botanical composition | en_ZA |
| dc.subject | Cultivated pasture | en_ZA |
| dc.subject | Rising plate meter | en_ZA |
| dc.subject | Comparative yield method | en_ZA |
| dc.subject | Meter stick | en_ZA |
| dc.subject | Dry-weight-rank method | en_ZA |
| dc.subject | Pastures -- South Africa -- Management | en_ZA |
| dc.subject | Forage plants | en_ZA |
| dc.subject | Pastures -- Growth -- Measurement -- Evaluation | en_ZA |
| dc.subject | Dissertation (M.Sc. (Animal, Wildlife and Grassland Sciences))--University of the Free State, 2009 | en_ZA |
| dc.title | Evaluation of techniques to determine the production potential of cultivated pastures | en_ZA |
| dc.type | Dissertation | en_ZA |