South African rangelands in combination with their surrounding homesteads occupy 13% of the entire land surface in South Africa. These rangelands are a source of forage for communal livestock. The rangelands in communal tenure system are degraded due to high human population and livestock numbers. The rangeland of Peddie was never evaluated since the introduction of Nguni Cattle Empowerment Project. Therefore, socio-ecological evaluation was conducted in order to interlink farmer‟s perceptions and scientific data to recommend appropriate rangeland management and restoration programme. Two structured questionnaires consisting of close and open ended questions were used to investigate farmer‟s perceptions on rangeland condition, dynamics, and their causes. Sixty households were randomly selected on the bases of livestock ownership and the membership in Nguni Cattle Project. In each household, any respondent of 20 years or greater, and a key informant of age greater than 40 years were selected. For scientific assessment of range condition, three homogenous vegetation units namely grassland, scattered and dense bushland were demarcated into four 100m x 50m replicates. In each replicate, two 100m transects were laid parallel to each other with 30m equidistant apart. The step point and harvesting method along each transect were employed for herbaceous species composition and biomass production. The point-to-tuft distance was also determined as a proxy for basal cover. Woody density, species composition and tree equivalents were determined in 200m2 belt transects in each HVU replicates. The germination method for soil seed bank evaluation was also employed to find plant species composition and density. The soil nutrients (OC, N, P, K, Na, Ca, Mg, Zn, Cu and Mn) and pH were analysed through solution preparation and observation under photospectrometer to determine functional capacity of the soil of Peddie rangeland. The farmer‟s perceptions comprised of 63% females and 37% males (n = 120) with a mean household of 8 people, 5 adults and 3 children. It was perceived by 93.3% respondents that the rangeland of Peddie have undergone changes over two decades. These changes were perceived by 83% respondents to be accompanied by decline in livestock numbers. Woody encroachment and overgrazing were perceived to be the major attributes of these vegetation changes. The scientific rangeland condition assessment confirmed that these changes were more pronounced as bush density increases. Dense bushland had a significantly high (p<0.05) encroached condition with 6650 trees ha-1 and 4909.5 TE ha-1 beyond the recommended thresholds of 2400 trees ha-1 and 2500 TE ha-1 respectively. Scattered bushland had a fair condition of 1950 trees ha-1 and 1198.1TE ha-1. Themeda triandra as a key species was significantly higher (p<0.05) in grassland (31.1%) than scattered (15.6%) and dense bushland (6.1%). There was a declining trend in biomass production from grassland to dense bushland. The summer biomass production was significantly higher (p<0.05) in grassland than scattered and dense bushland but winter biomass was not significantly different (p>0.05) from all homogenous vegetation units of Peddie rangeland. However, the soil fertility increased with an increase in bush density except organic carbon (OC) which was 1.61% in grassland, 1.46% in scattered and 1.53% in dense bushland respectively. Soil N, K, P, Mg2+ Na+, Ca2+, Cu, Zn, Mn and pH were significantly higher (p<0.05) in dense bushland than grassland and scattered bushland. High soil fertility in dense bushland may be attributed to by abscission of woody plants and litter decomposition. In the soil seed bank, the abundances of forbs were significantly higher than sedges (χ2 = 12, df = 1, p = 0.001) and grasses (χ2 = 8.333, df = 1, p = 0.004) in all homogenous vegetation units while sedges were not significantly different (χ2 = 3, df = 1, p = 0.083) from grasses. The Sorensen‟s index indicated that soil seed bank and extant vegetation were significantly different (p<0.05). Annual and biennial forbs and sedges had high abundances while perennial grasses formed a bulk in above ground vegetation. This provided an insight that a reliance on soil seed bank for restoration of Peddie rangeland would not be advisable because it can result in retrogression. The communal rangeland assessment provided clear qualitative and quantitative data when the combination of indigenous knowledge and scientific assessments was done. The rationale is that conclusions and recommendations of range assessment are relient on the farmer‟s perceptions pertinent to their livestock production systems and their rangeland management objectives. This study has shown that inclusion of communal farmers in policy making can provide better insight because those are the people experiencing the consequences of range degradation.

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From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / An erosion prediction method that has recently received wide attention in the United States is the universal soil loss equation which is given as: a=rklscp. Where a = estimated soil loss (tons/acre/year), r = a rainfall factor, k = a soil erodibility factor, l = a slope length factor, s = a slope gradient factor, c = a cropping-management factor, and p = an erosion control practice factor. Data collected on the walnut gulch experimental watershed in southeastern Arizona were used to estimate these factors for semiarid rangeland conditions. The equation was then tested with data from watersheds of 108 and 372 acres. The predicted value of annual sediment yield was 1.29 tons/acre/year as compared with an average 1.64 tons/acre/year for 4 years of data for the 108-acre watershed, and a sediment yield of 0.39 tons/acre/year was predicted for the 372-acre watershed as compared with the measured value of 0.52 tons/acre/year. Although good agreement was noted between predicted and actual sediment yield, additional work is needed before the equation can be applied to other areas of the southwest.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / A stochastic model is presented for the prediction of sediment yield in a semi-arid watershed based on rainfall data and watershed characteristics. Random variables which lead to uncertainty in the model are rainfall amount, storm duration, runoff, and peak flow. Soil conservation service formulas are used to compute the runoff and peak flow components of the universal soil loss equation, and a transformation of random variables is used to obtain the distribution function of sediment yield from the joint distribution of rainfall amount and storm duration. Applications of the model are in the planning of reservoirs and dams where the effective lifetime of the facility may be evaluated in terms of storage capacity as well as the effects of land management of the watershed. In order to calibrate the model and to evaluate the uncertainties involved, experimental data from the Atterbury watershed near Tucson, Arizona were used.