All CCF farms are located within a semi-arid environment, where the mean annual precipitation is 450 mm. The farms are geographically located between the 400 mm and 500 mm median annual rainfall isopleths. Local variations in rainfall between farms are experienced. There is marked seasonality with most rainfall occurring between November and April. There are three major seasons influencing the area climate: a wet-hot season (January – April), a dry-cold season (May – August) and an intermediate season (September – December) (Marker, 2004). The wet and intermediate seasons are characterized by extensive thundershowers and flooding, with considerable variation in the amount of precipitation between years (Barnard 1998). Maximum daily temperatures for the hottest months range between 33°C – 34°C, and the average daily minimum temperature for the coldest months varies from less than 2°C to more than 10°C (Van Der Merve, 1983; as in Erkilla & Siiskonnen, 1992). The average annual water deficit (evaporation) for CCF farms range between 1500mm – 1700mm (Mendelson et al 2002; as in de Klerk, 2004). The number of frost days experienced range from 5 – 10 (Le Roux & Esterhuyse, 1967; as in Erkilla & Siiskonen, 1992). The absolute minimum and maximum temperatures recorded in Namibia are -10°C and 48°C.
Geology and Soils
The Waterberg Plateau, a 4100-km2 sandstone uplift on the eastern periphery of the farms is the dominant geological feature of the region. All CCF farms are located within the Damara sequence geologic stratum, the oldest in the Waterberg region formed between 500 – 850 million years ago.
Farm Cheetahview contains three kopjes that arise over the flat farmland matrix at heights of 1651m 1690m and 1650m altitude above sea level respectively. On farm Elandsvreugde, a single kopje rises towards the southwestern farm boundary at 1621 m altitude above sea level. Soil types on all CCF farms fall into two main associations: – Eutric Regosols (Cheetahview, Boskop & southwestern Elandsvreugde) and Chromic Cambisols(Elandsvreugde) (Namibia CON Info, 2004). Eutric soils are fertile and contain a high saturation base, whereas bright colours characterize chromic soils (FAO soils classification system, undated). Preliminary soil results obtained on farm Elandsvreugde during 1996 indicated that 95% of the soil samples consisted of sandy – loam texture class. In addition, soil results obtained from farm Cheetahview during 2005 indicated various soil texture class distributions on the farm (Sandy – Loam 44%, Clay-Loam 33%, Loam 19%, and Sandy-Clay-Loam 4%). (See attached appendices for map layouts 1- soil map for Namibia, 2 locations where soil samples were taken at Cheetahview and Elandsvreugde).
The lithology of sedimentary and volcanic units of farm Elandsvreugde contains the Nd damara sequence undifferentiated – mainly schist, marble, and quartzite which covers the major parts of the farm. The south – western parts of the farm contains the Cgd damaran granitic rocks undifferentiated; the Nsc – swakop group marbles undifferentiated and Nn – nossib group undeferentiated (feldspathic quartzite, quartzite, arkose, conglomerate and greywacke: minor dolomites are found (Volkmann et al, 1988).
The lithology of sedimentary and volcanic units of farm Cheetahview contains of Nd damara sequence undifferentiated consisting mainly schist, marble and quartzite which covers most parts of the farm. The Cgd damaran granitic rocks, undifferentiated, occur mainly on the southwest parts of the farm. The Nsc swakop group marbles undifferentiated patches located mainly from the north central parts of the farm (Volkmann et al, 1988).
The lithology of sedimentary and volcanic units of farm Boskop contains the Cgd damaran granitic rocks, undifferentiated group, which covers most parts of the farm. Isolated patches of Nsc swakop group marbles undifferentiated occurs in some parts of the farm where the most of these rock types are located towards the Southwestern parts of the farm. Other rock types Nn – nossib group undifferentiated – feldspathic quartzite, quartzite, arkose, conglomerate and greywacke: minor dolomites are less distributed (Volkmann et al, 1988).
Water resources of the farms occur in two main forms i.e. surface and underground water sources. Water availability is disadvantaged by unpredictable climatic conditions (rainfall), and the underlying geology of the area. For most CCF farms (apart from Janhelpman) underground water aquifers are weak, limited and are found in cracks in a combination of sand, and rock (Hydrology map of Namibia, undated). Borehole developments on CCF farms were recorded to date back as far as 1930.
The Ministry of Agriculture Water and Forestry hydrology department registered three boreholes on Cheetahview. These boreholes were drilled up to a final depth of 43m, and were located in close proximity to earth dams. A total of four (4) boreholes were reportedly drilled on farm Boskop in close proximity with earth dams. The final depth of the wells reached 52m.
The topography of the farms is generally flat with slight undulations; consequently, rainfall run-off is slow and there are no permanent river systems on the farms. All farms occur within the moderate soil erosion risk region of Namibia (DRFN soil erosion map, undated). A number of man-made semi-permanent water reservoirs (earth dams) were developed since the 1960’s on these farms. Earth dams were developed in areas where seasonal swamps (vlei’s) occurred. Recharge to earth dams depends on seasonal rainfall. Water is channeled to earth dams via shallow stream networks, and in certain cases, man-made modifications were done to increase water flow to earth dams. A total of six earth dams are found on farm Cheetahview (3 large, an 2 small). On farm Boskop, four large earth dams are found (two are close to the main house). Elandsvreugde has a total of nine (9) earth dams.
The farms are situated in the Thornbush Savanna vegetation zone defined by Geiss (1971, as in Erkilla and Siiskonnen). Vegetation is typical of xeromorphic thornbush savanna with dominant woody plant genera consisting of Boscia, Dichrostachys, Grewia, Senegalia, Terminalia, and Vachellia. Understory vegetation is relatively sparse, although ephemeral forbs are present following rain. This region has been extensively modified over the last century through human-mediated causes compounded by natural climatic fluctuations ADDIN ENRfu (Louw and Seely, 1982; Prins and van der Jaeugd, 1993; Hoffmann, 1997; Pallet, 1997). Some native woody species such as Senegalia mellifera, Vachellia tortillis, and Dichrostachys cinerea have proliferated, and perennial grasses have been reduced throughout this area ADDIN ENRfu (Bester, 1996; Rhode, 1997). Until 1980, cattle farming was practiced on farm Elandsvreugde. Farms Boskop and Cheetahview are currently stocked with cattle, goats, sheep, horses and donkeys. Historical livestock Management practices on these farms may be responsible for the bush encroachment present. Farm Elandsvreugde contains a large open grass field that was formerly used for maize and sunflower production.
Woodland vegetation of more than 2m high are found at waterholes and places such as seasonal rivers and streams. These areas are characterized by species such as Acacia tortillis. Sandy soil patches on the farms are dominated by woodland woody genera consisting of Combretum, Terminalia, and Lonchocarpus. The vegetation structure for most farms is classified as a short shrubland where most dominant bush is below two (2) meters high.
The CCF Bush project has conducted research on the CCF farms in order to determine the density, species composition, and distribution of the woody and herbaceous species components. In addition, approximate volume and biomass yields of bush were estimated. According to preliminary results obtained from the CCF economic plots (2003) on farm Elandsvreugde, D. cinerea (40.2%), and S. mellifera (11%) makes up 51.2 % of the total woody stem density per hectare. Encroaching species such as V. tortilis occurs in low density on this farm, and were not detected in the economic plots. This species were observed to have localized distribution such as near waterholes, or previously cleared crop fields. Two non – encroaching species such as V. fleckii (22.43%) and V. reficiens (14.%) were common. The mean number of trees, volume and biomass per hectar for all species is 5014 ( + 449), 27.32 m3 ( + 12.9) and 12.29 (+ 5.8) tons respectively (Chakanga, 2003).
On farm Cheetahview, encroaching species such as D. cinerea and S. mellifera makes up 51 % of the total woody stem density per hectare with 34.81% and 15.76% respectively. The other encroaching species V. tortilis were less abundant, and contributed approximately 7% of the total woody species stem density per hectare. The mean woody stem density per hectare was estimated to be 4480 ind/ha (+ 257). Although no surveys were conducted on farms Boskop, species such as S. mellifera were observed to occur in higher proportions when compared to farms Elandsvreugde and Cheetahview. In total, seventeen (17) tree/shrub species occurring on CCF farmland are protected.