Bibliography: Land Degradation in South Africa project

treatments. Perennial grasses and shrubs were strongly influenced by rainfall

variation, with grazing treatments further influencing the rate and extent of

change. Only perennial grasses were almost eliminated by grazing during the

summer. (4) Community change was mostly driven by rainfall variation, but the

influence of grazing treatments on longer-lived plants became more important

over a longer time period. The community was therefore a matrix of longer-lived

perennial grasses and dwarf shrubs within which dramatic variations in the

abundance of annual grasses and ephemeral forbs took place. (5) The need is

discussed for long-term data sets and appropriate monitoring approaches, as aids

to a more complete understanding of the forces determining community structure

in semi-arid environments.

Ref ID : 2167

1548. O'Keeffe, J.H. The conservation of South African rivers.Anonymous

Pretoria:CSIR. 131, 1986.

Reprint : Not in File,

Keywords : CONSERVATION

Notes : South African National Scientific Programmes Report no. 131.

Ref ID : 2168

1549. O'Keeffe, J.H. and De Moor, F.C. Changes in the physico-chemistry and

benthic invertebrates of the Great Fish River, South Africa, following an inter-

basin transfer of water. Regulated Rivers: Research and Management 2:39-55,

1988.

Reprint : Not in File,

Ref ID : 2169

1550. O'Keeffe, J.H., Uys, M., and Bruton, M.N. Freshwater systems. In:

Environmental management in South Africa, edited by Fuggle, R.F. and Rabie,

M.A.Cape Town:Juta & Co. 1992,

Reprint : Not in File,

Ref ID : 2281

1551. O'Meagher, B., Du Pisani, L.G., and White, D.H. Evolution of drought

policy and related science in Australia and South Africa. Agricultural Systems

57(3):231-258, 1998.

Reprint : In File,

Keywords : DROUGHT; POLICY; CLIMATE; LAND DEGRADATION; MONITORING

Abstract : Australia and South Africa are dominated by extensive agriculture,

both countries being predominantly arid and exposed to a highly variable

climate. Limiting land degradation, maintaining the financial viability of

farms and improving the risk-management skills of farmers are common problems

which government and industry in both countries are attempting to address. Both

countries are currently refining their approaches to drought management, and

have been making substantial use of science in improving the monitoring and

assessment of drought, and the management of the land. Unlike the situation in

Australia, however, South Africa's approach is being reviewed against the

backdrop of fundamental reorientation of broader agricultural policies in the

context of that country's transition to a fully fledged democracy. The changing

approach to drought policy in South Africa can therefore only be fully

understood in the context of this borader process of change. This paper

compares the climate and agriculture of Australia and South Africa, and how

their different drought policies have evolved. Observations are made on the

role of scientists in providing advice to political decision makers, and ways in

which the process of decision making with respect to drought may be improved.

Ref ID : 2563

1552. O'Neil, D.H., Sneyd, J., Mzileni, N.T., Israel, S.H., and Njekwa, M. The

management and use of draught animals by small-holder farmers in the former

Transkei and Ciskei, Eastern Cape Province, South Africa. Research report DF&D,

Agriculture, University of Fort Hare.Anonymous University of Fort Hare,

Agricultural Department:DF&D. , 1999.

Reprint : Not in File,

Keywords : TRANSKEI; CISKEI; EASTERN CAPE; DROUGHT; LIVESTOCK PRODUCTION;

SOCIOECONOMIC ASPECTS; AGRICULTURAL PRODUCTION

Notes : The purpose of the study was to determine: attitudes to draught animal

ownership; how local small-holder farmers typically use and manage their draught

animals; and to gain some insight into their socio-economic circumstances. A

survey was undertaken of farmers and households in 19 districts in the Eastern

Cape Province of South Africa, concerning varying levels of animal and draught

animal ownership. About 94 households in the 19 districts were interviewed

using semi-structured questionnaires. Data was collected on demographic, socio-

economic, animal and crop factors. Each household owned an average of 5.4 oxen,

8.3 cows and 1.0 horses. Animals were used for draught by 79% of the farmers.

Only 22% used cows for draught with 12% using other animals for draught. The

most common uses were ploughing and harrowing (76%). Horses were kept for

riding. Most farmers preferred animals to tractors for crop prodcution tasks

(e.g. 85% for ploughing). A majority of farmers (91%) believe that it is

profitable to own draught animals, but 97% were concerned about the risks of

drought, theft and disease. The current management and use of draught animals

in the areas surveyed indicates that for those small-holder livestock farmers

wishing to maintain or increase their crop production, draught animal power at

present is an appropriate technology to use. It therefore merits promotion in

the region. This report is obtainable from the Faculty of Agriculture,

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

Ref ID : 1712

1553. O'Reagain, P.J. Plant structure and the acceptability of different grasses

to sheep. Journal of Range Management 46(3):232-236, 1993.

Reprint : In File,

Keywords : GRASSLAND; PLANT PHYSIOLOGY; GRAZING EFFECTS; PLANT-ANIMAL

INTERACTIONS; CLIMATE CHANGE

Abstract : Plant structure should be an important determinant of species

acceptability to grazing ungulates functioning under various time-energy

constraints. The acceptability of 9 grasses to sheep grazing a secondary

grassland community in spring, summer and autumn in SA was related to the

following species attributes: plant height, leaf table height, tussock diameter,

stemminess, percent leaf, leaf density, percent dry matter (DM), leaf tensile

strength, and leaf crude protein (CP). Species acceptability over the grazing

season was positively related to tussock diameter (P<0.05) but negatively

related (P<0.01) to leaf tensile strength and DM. Discriminant function

analysis successfully discriminated between species in different acceptability

classes in summer (P<0.05) and autumn (P<0.01) using a combination of plant

structure and leaf quality attributes. Correspondence analysis indicated that

preferred species were generally short and nonstemmy and had leaves of low DM,

low tensile strength, and high crude protein content. Conversely, avoided

species tended to be tall and stemmy with high leaf table height, and had leaves

of high DM and tensile strength but low CP levels. It is concluded that, for

sheep, acceptability is determined by a combination of plant structure and leaf

quality attributes.

Ref ID : 1854

1554. O'Reagain, P.J. Predicting animal production on sourveld: a sward-based

approach. African Journal of Range and Forage Science 13(3):124-130, 1996.

Reprint : In File,

Keywords : MODELS; VELD CONDITION

Abstract : Simulation models were developed to assess the effects of sward

structure and species composition on average daily gain (ADG) and seasonal live

mass gain (LWG) in cattle and sheep on Dohne Sourveld. The models used diet

quality and intake data collected from sites of different sward structures and

species compositions on this veld type. In model 1, predicted ADG was highest

at an optimum sward height (Hopt) of 60 - 80 mm for sheep and approximately 120

mm for cattle but Hopt is likely to decrease as forage quality declines through

the season. Species composition appeared to be the major determinant of ADG

above Hopt while sward height appeared to be more important below Hopt.

Potential rates of DM intake generally far exceeded predicted voluntary intake,

suggesting that on sourveld, intake is seldom likely to be restricted by the

effects of sward height on intake rate per se. In model 2, species composition

had a major effect on animal production with sites showing large differences in

predicted LWG. Significantly, site rankings in terms of predicted LWG were

different between cattle and sheep and showed only limited agreement with veld

condition score. In both models, small, apparently insignificant, differences

in dietary quality translated into major differences in predicted ADG and LWG.

Through their effects on diet quality, species composition and sward structure

thus both appear to be important determinants of animal production on Dohne

Sourveld. However, an optimum species composition and sward structure cannot be

specified as these variables are conditional upon each other as well as the

season and the animal species involved.

Ref ID : 1855

1555. O'Reagain, P.J. Predicting animal production on sourveld: a species-based

approach. African Journal of Range and Forage Science 13(3):113-123, 1996.

Reprint : In File,

Keywords : MODELS; ENERGY

Abstract : A simulation model was developed to predict average daily gain (ADG)

in cattle and sheep grazing different species and swards of different species

composition on Dohne Sourveld. The model was based upon measured ingestive and

digestive characteristics of different grass species and incorporates an

explicit digestive constraint based upon rumen mass and turnover rate.

Sensitivity analysis indicated that forage quality, through its effects on

digestion rate, had a far greater impact on predicted ADG than ingestion rate.

There were major differences between grass species in their predicted potential

to support ADG. Overall, predicted ADG was greatest for Hyparrhenia hirta, and

to a lesser extent for Cynodon dactylon, but lowest for Andropogon

appendiculatus, Eragrostis plana and Microchloa caffra. For all species,

predicted ADG declined through the grazing season and most species appeared

incapable of meeting animal maintenance energy requirements in winter.

Predicted ADG increased with plant height in all species until the seasonal

limit set by voluntary feed intake was reached. At all sites predicted ADG

declined through the grazing period but the magnitude and rate of this decline

was strongly dependent upon species composition in termrs of the nutritive value

and the relative and absolute abundance of the species present at a site.

Species composition, through its effect on diet quality, is therefore likely to

be a major determinant of animal production on Dohne Sourveld.

Ref ID : 1846

1556. O'Reagain, P.J. and Mentis, M.T. The effect of veld condition on the

quality of diet selected by cattle grazing in the Natal Sour Sandveld. Journal

of the Grasslands Society of Southern Africa 7(3):190-195, 1990.

Reprint : In File,

Keywords : VELD CONDITION

Abstract : The quality of diet selected by steers fistulated at the oesophagous

was related to veld condition in a simulated rotational grazing system on the

Natal Sour Sandveld. Six camps, ranging in veld condition score from 8,5 to

53%, were grazed simultaneously for a two-week period in spring, summer, autumn

and winter. Fistula samples were collected on the first, middle and last day of

a period of occupation in a camp. Samples were analysed in terms of crude

protein (CP), in vitro digestibility (IVD) and plant-part (%leaf, %stem and %

dead material) composition. Dietary quality in terms of CP, IVD and plant-part

composition was not related to veld condition but was dependent largely (P<0,01)

upon season and to a lesser extent upon period of occupation in a camp. It was

concluded that in sourveld areas, where dietary quality may be limiting, the

veld condition score may be a poor index of potential animal production.

Ref ID : 1756

1557. O'Reagain, P.J. and Turner, J.R. An evaluation of the empirical basis for

grazing management recommendations for rangeland in southern Africa. Journal of

the Grasslands Society of Southern Africa 9(1):38-49, 1992.

Reprint : In File,

Keywords : SOUTHERN AFRICA; STOCKING RATE; VELD MANAGEMENT; GRAZING EFFECTS;

LIVESTOCK PRODUCTION; VELD CONDITION; DESERTIFICATION CONTROL; RESTORATION

Abstract : Analysis of over 50 grazing experiments conducted in southern Africa

does not support certain management recommendations. Furthermore, the

conclusions of some experiments are questionable owing to poor experimental

design or confirmation bias. Based on available evidence, it was concluded that

(i) stocking rate has a major impact on range condition and animal production,

(ii) continuous and rotational grazing or pauci- and multi-camp systems differ

little in terms of their effects upon range condition or animal production,

(iii) sheep have a greater potential for range degradation than either cattle or

goats, but this effect may be ameliorated and sheep production increased by

stocking sheep with cattle at narrow ratios, (iv) separation of veld types

appears important, and (v) regular seeding or vigour rests, or rests to

accumulate fodder, appear essential. Simple grazing systems using adaptive and

opportunistic management are recommended.

Ref ID : 2312

1558. Odera, J.A. Preliminary inventory of traditional and local technical

knowledge, knowhow and practices in combating desertification in eastern and

southern Africa. Workshop held at Matera, Italy, from 8 - 14 July 1999, attended

by Dr. M. Timm Hoffman.Anonymous Anonymous Matera: 1999. Drylands of eastern and

southern Africa are characterized by scant and erratic rainfall, and shallow

soils. Land use is dominated by livestock development and wildlife conservation

with crop production remaining limited to moist areas. Land management is

dualist and based on customary and modern tenures. The report which is based on

visits and discussions held with experts from Djibouti, Botswana, Ethiopia,

Lesotho, Kenya, Somalia, Tanzania and Zibmabwe has examined the evolution of

agriculture in the region, from pre-colonial times through the influence of the

colonial era to the post independence period. It examines developments in land-

use and the role of technical knowledge in drought coping, management and

sustainable resources use from community experiences. The important roles of

traditional land and resources tenures, and community governance systems are

recognized and featured. Experiences from different communities show that

enforcement of tenurial arrangements was assured through traditional policy

fences embodied in sanctions based on shared patterns of beliefs, fear of

organization, public reprimand or payment of fines and/or physical confrontation

by the community. The scarcity of water which is a major constraint to dryland

development, has been addressed and traditional water management regimes such as

water harvesting techniques, range pitting, flood water spreading, rock

catchment, subsurface dams and digging of shallow wells presented and appraised.

Observations reveal that hand-dug wells, the oldest means for getting clean

water are promoted by communities themselves, although a few projects have

recently benefited from external assistances. Under the latter package,

community members have been trained on hand-pump maintenance thus enablng the

project to run smoothly under their own management. It is noted that livestock

remains the most viable way of utilizing the extensive range land resources

which in the past had relied heavily on nomadic pastoralism. The secret of its

success hinges on localized to tranzonal migration, minimizing risks through

herd dispersion, split grazing and assigning some animals to relatives and

friends in different locations on temporary care under tilia and mafisa systems.

Traditional systems particularly invest on herd accumulation, diversification

and optimization of the regenerative stock capacity, breeding and health

management as strategies for maximising production while minimizing risks.

Their concern and strategies for sustainable management of water resources,

management of pastures and biodiversity excel modern practices in many ways.

These practices were assured through intimate understandng of the soil, plants,

animals and the environment, supported by sophisticated grazing habits and

division of labour with the adult males responsible for governance and livestock

management, while the women make all major domestic decisions and crop

production. The children, women and old people herd small ruminants, lactating

and sick animals around the settlements. Cropping communities cultivate plots

in dispersed areas. Crop production is closely associated with miticulous

management of soil and water resources. The soils are highly erodable when bare

of the vegetation and management recognizes the important need for maintaining

soil and water conservation practices. Outstanding technologies include:

swidden agriculture, agroforestry practices, soil and water conservation

practices such as terracing and water harvesting. Local communities use a wide

range of indigenous technologies in energy management, drought coping and

mitigation mechanisms. Intimate knowledge of the environment has enabled

peasants and pastoralists to develop systems for classifying soils and the

vegetation, and indicators that signal imminent changes in environmental

quality, the coming of rain or dry spells. Skills in plant and animal breeding,

crop, and seed storage, pests and disease management, ethno-veterinary and

ethno-medicine are extremely outstanding. Post-harvest and food storage

technologies provided important avenues for boosting food security and drought

coping tactics. Although developments in energy systems had remained modest,

communities met most of their needs for cooking and heating from biomass fuel.

In a final chapter the report proposes implementation of the CCD's initiative

through a regional network with nodes at sadc and igad secretariats, supported

by national programmes in participating countries. The programme should cover

training, capacity building, documentation and analysis of TK, research and

development addressing validation and value- adding, and dissemination and

awareness creation. It is stressed that the programme should be implemented by

a tripartite partnership of CBO's, NGO's, donor agencies and ground-based

government entities and the private sector.

Reprint : In File,

Keywords : SOUTHERN AFRICA; RAINFALL; LAND USE; CONSERVATION; BOTSWANA; LESOTHO;

DROUGHT; POLICY; FLOODS; BIODIVERSITY; LABOUR; WATER CONSERVATION; AGROFORESTRY;

ENERGY

Ref ID : 403

1559. Olckers, T. and Hoffmann, J. Eighty years of biological weed control: Are

we winning the battle against aliens? A review of 80 years of biological

warfare. Veld & Flora 81(4):110-115, 1995.

Reprint : In File,

Keywords : ALIEN PLANTS; ENVIRONMENTAL HISTORY; CONSERVATION; FOREST

Notes : The author states that 1993 was the 80th anniversary of biological weed

control in SA and although several alien plant species have been controlled

successfully, many others remain a major problem in conservation areas, water

catchments, forests and agricultural lands. He defines biological weed control

and traces the process and history of weed control followed in SA. He describes

some successful weed-control programmes. He also points out some high and low

points experienced with alien acacia control. He mentions the use of fungal

pathogens, resistant weeds and concludes with ideas for the future.

Ref ID : 1675

1560. Olckers, T. and Zimmerman, H.G. Biological control of silverleaf

nightshade, Solanum elaeagnifolium, and bugweed, Solanum mauritianum,

(Solanaceae) in South Africa. Agriculture Ecosystems & Environment 37(1-3):137-

156, 1991.

Reprint : Not in File,

Keywords : DESERTIFICATION CONTROL; BUSH ENCROACHMENT

Ref ID : 649

1561. Oosthuizen, E.A. Sites for dams under the soil erosion schemes. Farming in

South Africa :158-159, 1936.

Reprint : In File,

Keywords : SOIL EROSION; GOVERNMENT INITIATIVES; EROSION CONTROL; SEDIMENTATION;

EROSION; IRRIGATION

Abstract : The author points out that it is generally known that dams under the

soil erosion schemes are built for (1) soil erosion control, (2) supplying

drinking water for animals, and (3) irrigation, and as the last-named item

occasions a good deal of difficulty, the present article is principally devoted

to this aspect. In summary, the five main points to consider when building an

irrigation dam are the following: (1) the economic possibilities of the

proposed irrigation scheme; (2) the suitability of the dam site; (3) the size of

the impounding area or basin, and the number of morgen which can be brought

under irrigation in relation to the cost of the dam; (4) the size and shape of

the catchment area; and (5) whether there is a suitable place for an adequate

spillway.

Ref ID : 1192

1562. Oosthuizen, J.J. Grootfontein agric. Grootfontein Agric 1(1):i-36, 1998.

Reprint : In File,

Notes : The Grootfontein Agric is a semiscientific journal of the Grootfontein

Development Institute. Its primary objective is to promote resource

utilization. As such, it is directed at the agricultural researcher, extension

officer, lecturer, student and farmer.

.

Ref ID : 2057

1563. OTA Harmful non-indigenous species in the United States.Anonymous

Washington DC:US Government Printing Office. OTA-F-565, 1993.

Reprint : Not in File,

Notes : Report no OTA-F-565, Office for Technology Assessment, United States

Congress.

Ref ID : 1714

1564. Owen-Smith, N. and Cooper, S.M. Plant palatability assessment and its

implications for plant-herbivore relations. Journal Grasslands Society of South

Africa 5(2):72-75, 1988.

Reprint : In File,

Keywords : NATURE RESERVES; SOIL NUTRIENTS; FAUNA; CLIMATE CHANGE; PLANT-ANIMAL

INTERACTIONS; PLANT PHYSIOLOGY

Abstract : An objective method used to assess the palatability of the foliage of

woody plant species to kudus, impalas and goats is described. Observations were