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Calobota sericea (Thunb.) Boatwr. & B.-E.van Wyk (Fabaceae) is a native legume from the semi-arid rangelands of South Africa. The species has been prioritised as a forage for water-limited agro-ecological areas. No information regarding the nutritional quality of C. sericea forage harvested at different phenological stages is currently available, limiting our knowledge as to the best time to harvest the forage. The aim of this study was to determine the nutritional quality of C. sericea forage harvested at five phenological stages. Results from the study show that crude protein, fibre, energy and digestibility of the forage decreased with plant maturity, but not all mineral nutrients showed the same trend. In general, C. sericea forage harvested at non-reproductive, early flower bud and full flower stages could provide sufficient energy and protein to maintain livestock condition. At these stages, the neutral detergent fibre and digestibility of the harvested materials are also good, indicating that intake and processing of these forage would not be a problem for the livestock. At these phenological stages most of the mineral nutrients were also sufficiently high to meet the minimum requirements of small stock. Thus, C. sericea forage harvested at the appropriate phenological stages could provide a useful source of forage for resource poor farmers. [ABSTRACT FROM AUTHOR]

Calobota sericea is a native legume of South Africa, confined to the water-limited rangelands, and it has recently been prioritised for additional characterisation regarding its pasture potential. In this study, we examined the growth characteristics of C. sericea under glasshouse conditions where water limitation was implemented at different plant ages, and for different durations. Results indicate that preferential resource allocation to the roots, as well as reduced stomatal conductance and transpiration, were early responses to water limitation, irrespective of the age at which water limitation was imposed, or the duration of water limitation. Under water-limited conditions, increased production of protective pigments, such as carotenoids and anthocyanins, was also observed, which helped in recovery after rewatering. It was concluded that after rewatering, all negative impacts of water limitation on morphology and physiology of C. sericea plants were generally returned to well-watered levels. This suggests that C. sericea plants employ a wide range of phenotypic adjustments in response to water limitation, which makes the plants well adapted to areas with high rainfall variability. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Several methods to rehabilitate old cropping lands in the Cederberg Mountains were tested to determine what type of soil disturbance, if any, and which of five indigenous perennial plant species are the most successful and economically feasible. Old lands are dominated by the unpalatable and poisonous, pioneer perennialGalenia africana. A complete randomised block design was followed with eight treatments and four replicates. All treatments, excluding the control, included re-seeding with five palatable species from the region. Soil disturbance was important with best results after three years in the ploughing-and-seeding and rolling-and-seeding treatments, which were also the most cost-effective treatments. Rainfall played a major role, with good germination in year one, but after a dry summer most of the new seedlings died. After three years the grassesChaetobromus involucratussubsp.dregeanusandEhrharta calycina, followed by the dwarf shrubTripteris sinuata, established the best, but less than 1% of the seed sown established. The near-absence of perennial species in the soil seedbank and above ground necessitate the addition of seed. In conjunction with this, applying mechanical soil disturbance using an environmentally-friendly method, such as a knife roller, is advised to rehabilitate old croplands to a more productive state for herbivores. [ABSTRACT FROM PUBLISHER]

Following a field campaign to determine the species composition, canopy cover, aboveground annual production and leaf area index (LAI) of the semi-arid savanna of north-western Namibia, we present a production model that can be used by graziers to determine the livestock carrying capacity. The model predicts the annual aboveground net primary production (ANPP) from regression equations of canopy cover by annual production fraction for plant functional classes. We tested the output of the model against another fully independent net primary production (NPP) model, namely the MODIS NPP product. The mean MODIS NPP for the 29 sites was 343 ± 22 kg dry matter (DM) ha−1y−1as opposed to 285 ± 142 kg DM ha−1y−1for the fAP model that used the regression method (p< 0.01). As a proof of concept, these landscape-scale ANPP values are used to calculate a recommended livestock carrying capacity for the Ehirovipuka Communal Conservancy, a 1 980 km2communal area with both wildlife and livestock populations. In addition, we also provide details of a field method for predicting landscape-scale LAI from line transect data. This approach can be used to ground reference the LAI values generated from the MODIS LAI product. [ABSTRACT FROM PUBLISHER]

The Leliefontein communal area in Namaqualand is grazed by mixed species herds that have multiple benefits for pastoralists. This study assessed how the management (herding and free-ranging) of different livestock herds affects their feeding ecology during the wet and dry seasons in a semi-arid shrubland. By using direct observations of livestock grazing in the field, we established their habitat preferences, diet selection and resources overlap. Results indicate that all free-ranging livestock can be considered grazers with cattle being selective. When sheep are herded, they tend to be more generalist feeders and herded goats are browsers. Livestock diet selection and forage preferences are largely linked to the habitats in which they graze and browse. Dietary overlap is highest between free-ranging livestock irrespective of season, whereas herded livestock are able to consume a food source with little potential competition from other livestock. Although the wet-season annual forage resources are able to sustain the livestock population in Leliefontein, this study concludes that the overdependence on annual vegetation would make livestock vulnerable during drought periods when forage production is low. [ABSTRACT FROM PUBLISHER]