Effect of Enclosure on Range Botanical Composition, Forage Productivity, Diet Selection, and Intake by SheepGrazing at El-Khuwei Locality, North Kordofan State, Sudan

Abstract

This study was conducted at El- khuwei Locality, North Kordofan State, Sudan. Two sites were selected El-Rosa enclosure and a control in the open area nearby. The overall objective was to provide information that contributes to a better understanding of the plant- animal interactions, and thereby develop a more resilient and sustainable livestock production system based on natural rangelands. Materials and methods of this study included a taxonomic study on range plants which was based on fresh plants specimens collected from the rangelands. These specimens were prepared, examined, identified, described and documented. Range vegetation measurements were then conducted and botanical composition of the diet selected by sheep was determined using the bite count technique. Moreover, voluntary feed intake was assessed using the product of the quantity of faeces collected over a specific period of time and in vitro digestion coefficient of forage plants selected by sheep. Chemical composition of the biomass, the diet selected and of some plants of interest was performed. The perception of pastoralists and their impact on the use of rangelands was investigated through the collection of data from the livestock raisers, using a questionnaire and group discussions. The taxonomic study of range plants revealed 74 species, belonging to 68 genera and 38 families. The three species that had high percentage in botanical composition in the enclosure range were Cenchrus biflorus(27.6%), Ipomea eriocarpa (20.2%) and Eragrostis tremula (19.2%). At seed set stage the dominant species were Acanthus spp. (18.5%), Cenchrus biflorus (15.0%) and Merremia omarginata (7%). On the open range Cenchrus biflorus was dominant (24.0%) followed by Echniochloa colonum (13%) and Sida alba (6.5%). The Percent vegetation cover, bare land and litter in the enclosure range were 71.5%, 15.5 and 11.5 respectively. That of open range site was 57.0%, 32.2% and 10.0 respectively. These results indicate that the range productivity was enhanced by the application of fencing compared with open range. In this study the carrying capacity, based on the flowering stage calculations, was 3.4 ha/TLU/year in enclosure range and 1.8 ha/TLU/year in the open range. In the flowering season plants with highest relative preference index (RPI) at the in the enclosure range were Zornia spp. (12.9), Merremia spp. (12.6) and Desmodium spp. (2.0). In the open range the plants with highest (RPI) were Desmodium spp. (15.9), Ipomea eriocapa (15.7) and Echniochloa colonum (5.1). The most important plants selected by sheep at the seed set stage in the enclosure range as indicated by RPI were Ceratotheca spp. (22.4), Zornia spp. (2.1) Desmodium spp .and Eragrostis tremula (1.7) each .In the open range the plants with highest RPI were Desmodium spp. (10.4), Zornia spp. (6.5) and Ipomea eriocapa (2.5). The crude protein (CP %) of biomass vegetation at flowering stage in enclosure range was 10.9%. That of the simulated diet at the same time was 15.3%. In the open range CP% of biomass vegetation was 10 %. That of the simulated diet at the same time was 11.9%. Individual herbaceous plants found to contain high % CP were Acanthus spp. (18.4%), Zornia spp. (16.6%) and Desmodium spp. (16.6%). The study on rangeland management and pastoralists’ perceptions on rangeland resources and utilization were meant to improve our understanding of the interactions between the human and livestock population and the environment from the pastoralists’ standpoint. This should give a validation of the scientific methods we adopted at least in part. Many of the plants that had high RPI were also reported by pastoralists as preferred plants. It was concluded that sheep can select a diet superior to the average quality of the biomass vegetation. It was also concluded that the most preferred plants by sheep in this study were Desmodium dichotomum, Zornia spp., and Ceratotheca spp. It is recommended that these findings should be considered as a basis for an informed management system in the El-Khuwei Locality which will be invaluable in developing sustainable management strategies for use by pastoralists.