Bibliography: Land Degradation in South Africa project

that respondents' perceptions relating to recommended veld management provided

information for future extension inputs, but relationships with measures of

agricultural progressiveness were not significant. All contacts with sources of

information, except extension office contact, were significantly related to veld

management efficiency. Suggestions are made for communication strategy aimed at

improving grazing management and utilisation. This thesis is available at the

Document Centre, Agriculture, University of Fort Hare. See also ID ref. no

2339.

Ref ID : 2453

1653. Ristow, W.E. and Bembridge, T.J. Farmer characteristics and the adoption

of grazing management practices in the King William's Town and Komga districts.

South African Journal of Agricultural Extension , 1993.

Reprint : Not in File,

Keywords : STOCKING RATE; FARMING SYSTEMS; CISKEI; AGRICULTURAL EXTENSION;

LIVESTOCK PRODUCTION; GRAZING EFFECTS; AGRICULTURAL DEVELOPMENT; ECONOMIC

ASPECTS

Notes : The purpose of the study was to investigate the veld management

practices in the King William's Town and Komga districts as a benchmark for

future extension programmes. The data comes from a 25% stratified random sample

on the basis of 4 relatively homogeneous livestock farming areas in the King

William's Town and Komga districts, comprising 68 farmers who owned at least 50

head of cattle and 300 sheep. A detailed questionnaire accompanied by field

observations was tested and used to gather information for the study. The

majority of livestock farmers fell in the economically active age group and they

were well educated. Levels of managerial aptitude, grazing management knowledge

and efficiency were below optimum. Mass media had little impact on the grazing

management. There was an informal leadership network but little group contact.

Extension workers had contact mainly with progressive farmers. There were

deficiencies in adoption of recommended stocking rates, grazing periods,

rotational resting, bush control and farm development. Some practices were

adopted independently of others. The result of the study suggests that the more

progressive farmers and extension and research workers actually seek each other

out. Messages need to be conveyed to farmers through all possible channels and

media on a planned basis, incorporating short-term proof of economic and

ecological benefits. Demonstrations and/or adoptive research in co-operation

with selected farmers among the middle 50% category, whose farms are

representative of farming systems, are likely to accelerate technology transfer.

This article is obtainable from the Document Centre, Agriculture, University of

Fort Hare. See also ID ref. no. 2339.

Ref ID : 1717

1654. Rivers-Moore, N.A. and Samways, M.J. Game and cattle trampling, and

impacts of human dwellings on arthropods at a game park boundary. Biodiversity

and Conservation 5:1545-1556, 1996.

Reprint : In File,

Keywords : GRASSLAND; LAND USE; STATISTICS; NATURE RESERVES; BIODIVERSITY;

PLANT-ANIMAL INTERACTIONS

Abstract : Seven grassland sites were sampled at South Africa's Hluhluwe-

Umfolozi Game Park boundary with the surrounding land, to assess changes in

arthropod diversity in response to land use. Epigaeic arthropods were sampled

using pitfall traps and a sweep net. In all, 262 morphospecies were collected,

but this is an underestimate of total local species richness. Fifty percent of

the species caught were single occurrences. The number of species, families and

orders represented at each of the seven sites was not significantly different,

but the number of individuals was significantly different. Between-site

comparisons, using multivariate statistics, did not reveal any strong site

groupings, with all sites being unique. The conclusion is that the reserve

boundary does not significantly divide arthropod diversity on a simple inside-

versus-outside basis. A major factor influencing the arthropod assemblages was

intensity of land use. Indigenous game animals and domestic cattle had the same

effect, and it was the intensity of trampling that was important rather than the

type of trampling. Human settlements had a major impoverishing effect. The

Coleoptera families, Cicindelidae, Staphylindae and Carabidae, were particularly

sensitive indicator taxa of land use. Scarabaeidae species were the only group

that were severely affected by the fence boundary, simply because their food

source, the faeces of large native mammals, was inside, leaving them without

resources outside the reserve.

Ref ID : 1429

1655. Roberts, B.R. Veldbeheer- die hoeksteen van bewaringsboerdery.Anonymous

Pretoria:Departement van Landbou-Tegniese Dienste. 19:1-22, 1965.

Reprint : In File,

Keywords : CONSERVATION; SUBSIDIES; LAND DEGRADATION; FIRE; VELD MANAGEMENT;

LAND USE

Notes : The author believes that the time has come where conservation must be

taken seriously. The article deals with the following issues: (1) approaches to

exploitation of natural resources; (2) catchment areas; (3) biological

conservation; (4) the philosophy of conservation; (4) constructive aims of

natural resource use; (5) a paradise of insanity (subsidies); (6) planning

ground use; (7) conservation patterns; (8) district planning; (9) early attempts

to conserve; (10) practical planning; (11) fundamental causes of land

degradation; (12) veld conservation in the future; (13) dangerous

generalisations; (14) amount of wool per sheep; (15) acidification of the veld;

(16) rotational grazing; (17) choosing the optimal season; (18) fires; (19)

leaks and concentrations; (20) methods of nature; (21) survival of the fittest;

(22) additional structures; (23) regrowth; and (24) problems with termites.

Ref ID : 333

1656. Roberts, D.F. An analysis of the amount of silt carried by South African

rivers. Trans.S.Afr.Soc.civ.Engrs. 2(5):147-159, 1952.

Reprint : In File,

Keywords : SOIL EROSION; SEDIMENTATION; IRRIGATION

Notes : This paper summarises all the data available to the Irrigation

Department concerning the silt load of South African rivers. It also presents a

method of determing the probable useful life of a dam built across a silty

river.

Ref ID : 476

1657. Roberts, P. The development of a morphometric model for the estimation of

mean annual sediment yield in ungauged catchments.Rhodes University. , 1975.

Master of Science.

Reprint : Not in File,

Keywords : SOIL EROSION; SEDIMENTATION; MODELS

Ref ID : 631

1658. Robertson, T.C. Erosion: Is climate or man the culprit? Veldtrust

XIII(1):16,-17,19, 1952.

Reprint : In File,

Keywords : SOIL EROSION; VELD MANAGEMENT; GRAZING EFFECTS; CLIMATE; CLIMATE

CHANGE

Notes : This article spells out the debate which raged at the time, concerning

the issue of whether the apparently ever-increasing desert (into the more humid

Karoo areas) is caused predominantly by human beings or by climate change. Drs.

Tidmarsh and Acocks stress climate change as the culprit and use biological

evidence to support their hypothesis. Dr. Kokot, on the other hand, believes

deterioration of the land is firmly due to humans' abuse of the land.

Ref ID : 624

1659. Robertson, T.C. Soil is life, Cape Town:Cape & Transvaal Printer Limited,

1968.pp. 3-56.

Reprint : In File,

Keywords : SOIL EROSION; SOIL NUTRIENTS; VELD MANAGEMENT; SUSTAINABLE

AGRICULTURE

Ref ID : 1464

1660. Robertson, T.C. Vanishing spoors: saving our soil: birthplace of an idea.

Ekos 1(4):31-32, 1981.

Reprint : Not in File,

Keywords : SOIL CONSERVATION; DESERTIFICATION CONTROL

Ref ID : 1104

1661. Rohde, R.F. Looking into the past: Interpretations of vegetation change in

Western Namibia based on matched photography. Dinteria (25):121-149, 1997.

Reprint : In File,

Keywords : ENVIRONMENTAL HISTORY; VEGETATION CHANGE; SAVANNA; NAMIBIA;

DESERTIFICATION ASSESSMENT; METHODOLOGIES; LAND TENURE; COMMUNAL AREA; RAINFALL;

SATELLITE IMAGERY; LAND DEGRADATION; POLICY; LAND REFORM

Abstract : This article describes the use of matched photography as a

methodology for interpreting environmental change. It provides an overview of

one aspect of the author's current research into property relations and options

for land tenure reform within the communal areas of Western Namibia.

Photogarphs from four sites raise questions about the history of vegetation

change in communal settlements, communal rangeland, commercial farm land and

ephemeral rivers in western Namibia. Repeat photography provides high quality

information about vegetation change within a limited area. It can be used in

conjunction with other methods of vegetation sampling, analysis of rainfall

records, satellite imagery, aerial photography, livestock records, historical

accounts and anthroplogical research in order to construct a broader

interpretation of environmental dynamics. This methodology has more general

applications in Namibia today and can be used by both students and professionals

in research and development programmes dealing with desertification, rangeland

management and environmental education. Interpreations of the matched

photographs repesented in this article indicate that vegation changes have

occurred but these cannot be solely attributed to human-induced processes of

degradation, especially in the communal areas studied. This evidence suggests

that assumptions about land degradation need to be carefully examined before

they are incorporated into policies related to land reform and natural resource

use.

Ref ID : 2574

1662. Romold, A.L. and Sandham, T. Present adaptation, social change and

communal resource management among rural dwellers in Ciskei, South Africa. 1996.

Reprint : Not in File,

Keywords : CISKEI; SOCIOECONOMIC ASPECTS; RURAL DEVELOPMENT; POLITICAL ASPECTS

Notes : The purpose of the study was to describe and analyse local conditions in

rural villages due to political changes in South Africa after the abolition of

the apartheid system. The study was conducted through formal interviews, veld

assessment survey observations and informal conversations. For interviews, four

villages from the Victoria East district were visited. The study concluded that

there were large income differences in the study areas. Households which earned

a local wage or income, had better living standards. Pension income was

substantial, with 50% of the income being derived from pensions. The study

further revealed a trend of social differentiation between those with different

living standards. This masters thesis is obtainable from the Document Centre,

Agriculture, University of Fort Hare. See also ID ref. no. 2339.

Ref ID : 334

1663. Rooseboom, A. Melting en analise van sedimentafvoer in riviere.Anonymous

Pretoria:Department of Water Affairs. 58, 1974.

Reprint : Not in File,

Keywords : SOIL EROSION; SEDIMENTATION

Ref ID : 477

1664. Rooseboom, A. Sedimenteerlating in damkomme.Anonymous Pretoria:Department

of Water Affairs. Technical Report 63, 1975.

Reprint : Not in File,

Keywords : SOIL EROSION; SEDIMENTATION

Ref ID : 335

1665. Rooseboom, A. Sedimentproduksiekaart vir Suid-Afrika/(Sediment production

chart for South Africa).Anonymous Department of Water Affairs. 61, 1975.

Reprint : Not in File,

Keywords : SOIL EROSION; SEDIMENTATION

Notes : This is an unpublished report.

Ref ID : 336

1666. Rooseboom, A. Sedimentafvoer in riviere en damkomme/Sediment discharge in

rivers and dam basins. D.Sc.Ing.Verhandeling U. , 1976.

Reprint : Not in File,

Keywords : SOIL EROSION; SEDIMENTATION; HYDROLOGY

Ref ID : 478

1667. Rooseboom, A. Reservoir sediment deposition rates. Proceedings of the

Second International Congress on Large Dams, Mexico.Anonymous Anonymous , 1976.

Reprint : Not in File,

Keywords : SOIL EROSION; SEDIMENTATION

Ref ID : 264

1668. Rooseboom, A. Sedimentafvoer in Suider-Afrikaanse riviere/Sediment

discharge in southern African rivers. Water SA 4(1):14-17, 1978.

Reprint : In File,

Keywords : SOIL EROSION; SEDIMENTATION

Abstract : This paper describes sediment discharge patterns in Southern African

rivers together with summarized results of a comprehensive analysis of available

data. Observed variations in sediment yield as functions of time and space are

depicted for Southern Africa.

It has been found that for different catchments in Southern Africa the annual

sediment yield varies from less than 10 t/km2 to more than 1000 t/km2.

Sediment loads transported by local rivers consist mainly of small particles

(<0,2mm). As a result, it is the availability of sediment and not the carrying

capacity of a river that determines how much sediment is carried at any instant.

It follows that for any typical river section there is no specific relationship

between sediment load and water discharge.

It has been found that during the period 1930-1970 the total average sediment

load of the major South African river system decreased by more than 50%. This

decrease can be attributed mainly to a decrease in the amount of easily erodable

material over part of the catchment.

Ref ID : 337

1669. Rooseboom, A. Report on the effect of landuse and management on sediment

production. Proc. Symp. on areas of low precipitation.Anonymous Anonymous

Canberra: 1979.

Reprint : Not in File,

Keywords : SOIL EROSION; SEDIMENTATION; LAND USE; VELD MANAGEMENT; CULTIVATION

Ref ID : 2176

1670. Rooseboom, A. Overview document: sediment transport in rivers and

reservoirs - a southern African perspective.Anonymous Water Research Commission.

297/1/92, 1992.

Reprint : Not in File,

Ref ID : 479

1671. Rooseboom, A. Sediment transport in rivers and reservoirs - a southern

African perspective.Anonymous Pretoria:Water Research Commission. WRC Report

297/1/92:i-7.47, 1992. This document provides a southern African overview on

sediment transport in rivers and reservoirs. The various approaches to sediment

sampling and data processing techniques during the past sixty years are

described. A fundamental treatise on open channel flow and associated hydraulic

sediment transport processes, based on the principle of conservation of stream

power is given. This approach provides a logical and comprehensible description

of the processes and has the advantage that it was developed specifically for

open channel flow, unlike most other approaches which were adopted from

aeronautical or pipe flow theory. Observed sediment yield patterns in southern

African rivers are described, as well as methods to make meaningful estimates of

average annual sediment loads. A summary is given of work done to develop the

new (1992) sediment yield map of southern Africa. This includes the sub-

division of the region into sub-regions of equal sediment yield potential and

the use of various techniques in an attempt to quantify the variability which is

encountered in sediment yields. The methodology which is to be used to obtain

estimates of sediment yield values for ungauged catchments by means of the new

sediment yield map is described. A comprehensive bibliography on southern

Africa sediment transport and related subjects is included.

Reprint : In File,

Keywords : SOIL EROSION; SEDIMENTATION; CONSERVATION; MAPS; SOUTHERN AFRICA;

METHODOLOGIES; BIBLIOGRAPHY

Ref ID : 338

1672. Rooseboom, A. and Goister, E.A.N. Brandvleidam, Papenkuilsvalleistuwal,

Theewaterskloofdam. Ondersoek na waaisandtoestande. Finale verslag van die

interdepartementele waaisandwerkgroep.Anonymous Pretoria:Department of Water

Affairs. P.0810/00/01/79, 1979.

Reprint : Not in File,

Keywords : WIND EROSION; WESTERN CAPE

Ref ID : 339

1673. Rooseboom, A. and Harmse, H.J.v. Changes in the sediment load of the

Orange River during the period 1929-1969. The Hydrology of areas of low

precipitation. Proceedings of the Canberra Symposium.Anonymous Anonymous IAHS

Publication. 128:459-479, 1979.

Reprint : Not in File,

Keywords : SOIL EROSION; SEDIMENTATION; HYDROLOGY; ENVIRONMENTAL HISTORY

Ref ID : 340

1674. Rooseboom, A. and Maas, N.F. Sedimentafvoer in die Oranje-, Tugela- en

Pongolariviere/Sediment discharge in the Orange, Tugela and Pongola

rivers.Anonymous Department of Water Affairs. 59, 1974.

Reprint : Not in File,

Keywords : SOIL EROSION; SEDIMENTATION

Ref ID : 480

1675. Rooseboom, A. and Mulke, F. Erosion initiation. Recent Developments in the

Explanation and Prediction of Sediment Yield. (Proceedings of the Exeter

Symposium, July 1982).Anonymous Anonymous IAHS Publication. 137:59-66, 1982.

Critical conditions for both cohesionless and cohesive materials are analysed in

terms of applied power. Power applied by a stream along its bed in maintaining

motion is compared to the power required to dislodge bed particles. In the case

of cohesionless materials, unique mathematical relationships have been derived

for both laminar and turbulent flow conditions. A theoretical relationship has

also been established for cohesive materials. This relationship was calibrated

with field data for cases of erosion on steep slopes.

Reprint : In File,

Keywords : SOIL EROSION; SEDIMENTATION; EROSION

Ref ID : 481

1676. Rooseboom, A., Verster, E., Zietsman, H.L., and Lotriet, H.H. The

development of the new sediment yield map of southern Africa. Report to the

Water Research Commission by Sigma Beta.Anonymous Pretoria:Water Research

Commission. WRC Report 297/2/92:i-7.3, 1992. This document deals with the

technical aspects concerning the preparation of the new sediment yield map.

Information on sediment yield values for southern Africa was derived mainly from

reservoir re-surveys performed by the Department of Watern Affairs, and also

from a number of South African river gauging stations and recorded sediment data

for Lesotho, collected by Makhoalibe (1984). Using the capabilities available

on GIS, maps of various physical and geographical features of southern Africa

which influence sediment yields were prepared and placed on GIS. These

included: (1) a basic erosion index map indicating the basic yield of different

regions; (2) a land use map based on the value of agricultural products sold in

1975; (3) an average slope map depicting the energy gradients for defining

sediment transport capacities; and (4) a rainfall erosivity map based on EI30

values compiled by Smithen (1981) for a ten year return period. Analysis or

calibration of data for southern Africa as a whole is not possible due to the

geographical diversity of the sub-continent. The region was therefore divided

into nine relatively homogeneous sub-regions. Various methods were used in an

attempt to calibrate the new sediment yield map. (1) With the aid of multiple

linear regression techniques an attempt was made to link sub-areas with

differing yield potential and land-uses to their observed sediment yields. This

attempt failed due to the lack of significance of overall model results as well

as of individual variables, intercorrelation between independent variables,

large standard errors and physically insignificant results. (2) A mathematical

model developed by Rooseboom (1992) describes turbulent transport of sediments

through catchments but could not be calibrated due to the fact that sediment

availability rather than transporting capacity proves to be the limiting factor

in determining sediment yields in practically all cases. (3) Statistical

analysis was eventually performed on a regional basis in order to overcome the

wide variability observed in sediment yields. The fundamental assumption here

was that sediment availability is the determinning factor in sediment yield

processes across southern Africa. Yield values were standardized for all

regions and the log generalised extreme value distribution with a negative skew

was found to provide the best fit of the data. The relationship between yield

and catchment size was examined. Mean values and confidence bands of sediment

yield values showed a strong tendency to converge to a regional mean value with

increasing catchment size. A method for estimating sediment yields from

ungauged catchments based on the results of the statistical analysis is

presented which allows for confidence limits to be affixed to estimated yields

from ungauged catchments. All the original main objectives of the research

project viz. to: (1) collate all information relevant to sediment yields and to

re-assess earlier data; (2) investigate relationships between yields and the

variables that determine yield; (3) develop a new yield map making use of the

GIS system and to calibrate this map; and (4) compile a background document

(Rooseboom 1992), have been covered in the project.

Reprint : In File,

Keywords : SOIL EROSION; SEDIMENTATION; MODELS; MAPS; SOUTHERN AFRICA; LESOTHO;

EROSION; LAND USE; ENERGY; RAINFALL; RAINFALL EROSIVITY; AID

Ref ID : 1277

1677. Roques, K.G. Shrub encroachment in Swaziland: dynamics, and the relative

importance of causal factors.University of East Anglia, Norwich. :1-73, 1997.

Shrub encroachment into savanna is a widespread phenomenon that can greatly

reduce the productivity of the grass layer. This study was conducted to provide

a quantification of the speed, continuity in time, and reversibility of the

process of encroachment between 1947 and 1997 in terms of shrub cover and

density using aerial photographs and field census. The relative importance of

the hypotheses that shrub encroachment is facilitated by 1) sustained heavy

grazing, 2) cessation of burning, 3) reduced browsing, 4) elevated rainfall, 5)

specific soil types, and 6) low initial shurb cover were tested employing land-

use contrasts in a quasi-experimental design. Shrub cover increased from 2.4%

to 31% over 43 years. The shrub population reached an equilibrium density

maintained by disturbance forces. Shrub encroachment can be reversed by drought