Forage legumes from the Mediterranean Fynbos biome of South Africa with potential for domestication: slope aspect affects tissue fibre and mineral composition

Fabaceae plants contribute greatly to a high quality of pasture in rangelands, because of high levels of protein in their tissues. Despite this established importance, only a few southern African legumes have been evaluated for nutritional value and domestication. The Overberg renosterveld vegetation of the Fynbos biome occupies undulating landscapes that have multiple slope aspects, creating variable microclimatic conditions affecting nutrient dynamics, species richness and plant chemical compositions. We assessed the effect of slope aspect on fiber and mineral composition of forage species present to provide information on the importance of slope for species characterization and nutritional value for domestication. Tissue samples from six replicates of the same species occurring on opposing aspects were collected for nutritional assessment. Results on the data showed that fibre and mineral composition differed in species occurring on different slopes, albeit with few exceptions. The concentrations of P, K and Mg in some species were significantly higher on the cooler and wetter south facing slopes relative to north facing slopes. Nutrient elements in soil samples collected from each site varied with slope aspects and elements. It is recommended that topography should be considered when studying forage nutritional assessments as part of future domestication programs

Native legume species as potential fodder crops in the mediterranean renosterveld shrubland, South Africa

The limited grazeable size of renosterveld vegetation in the Western Cape warranted assessment of chemical and fibre composition of the species to determine their nutritive value. We hypothesised that Fabaceae has chemically superior palatable species relative to Poaceae, Asteraceae and Asparagaceae species in the area. Plant samples were collected in the Overberg region from 11 sites. The species sampled from these four families Fabaceae, Poaceae, Asteraceae, and Asparagaceae were analysed for macro- and micro-elements, fibre and secondary compounds. At each site, replicated soil samples were also collected and analysed for pH, macro- and micro-elements. Fabaceae recorded the greatest concentration of crude protein, but the Poaceae was the most fibrous relative to Fabaceae and Asteraceae. All the species contained adequate levels of nutrients except P, Zn and sometimes Cu. Soil concentration of macronutrients and carbon in the soil varied with location. Based on crude protein, neutral detergent fibre and digestibility, the three most important parameters defining forage quality, the Fabaceae species Aspalathus hispida, A. angustifolia, A. nigra and A. submissa were regarded as superior forage species in the Mediterranean renosterveld. Livestock relying on only the renosterveld species in the Western Cape as forages should receive P and Zn supplements