A Critical Evaluation of the Capital Theory Approach to Sustainable Development

Irrigation farmers in the lower reaches of the Vaal and Riet Rivers are experiencing substantial yield reductions in certain crops and more profitable crops have been withdrawn from production, hypothesised, as a result of generally poor but especially fluctuating water quality. In this paper secondary data is used in a linear programming model to test this hypothesis by calculating the potential loss in farm level optimal returns. The model is static with a time frame of two production seasons. Linear crop-water quality production functions (Ayers & Westcot, 1983; adapted from Maas & Hoffmann, 1977) are used to calculate net returns for the eight most common crops grown. Results show optimal enterprise composition under various water quality situations. Leaching is justified financially and there is a strong motivation for a change in the current water pricing system. SALMOD (Salinity and Leaching Model for Optimal irrigation Development) is the Excel Solver model used to derive the preliminary results, but is currently being developed further in GAMS (General Algebraic Modelling System). Useful results have already been obtained on which this paper is based. The ultimate aim for SALMOD is a mathematical model using dynamic optimisation, simulation and risk modelling techniques to aid in whole farm and system level management decisions to ensure sustainable irrigation agriculture under stochastic river water quality conditions.International Development,

Modelling the marginal revenue of water in selected agricultural commodities: A panel data approach

South Africa is a water-stressed country where water availability is an important constraint to economic and social development, and will become even more so in the future if this scarce resource is not managed effectively. In order to manage this scarce supply of water, we need to value it. This study focuses on the value of water in the agricultural sector, in particular the marginal revenue of water for six irrigation commodities namely avocados, bananas, grapefruit, mangoes, oranges and sugarcane. A quadratic production function was fitted with an SUR model specification in a panel data study from 1975 to 2002 to obtain marginal revenue functions for each of the six commodities. We found that mangoes are the most efficient commodity in its water use relative to revenue generated (marginal revenue of water equals R25.43/m³ in 2002) and sugarcane the least efficient (marginal revenue of water equals R1.67/m³ in 2002). The marginal revenue of water is not an indication of the true “market” price. Neither is it an indication what the administered price should be. The marginal revenue of water is rather a guideline for policy makers to determine which industries or commodities within an industry can generate the largest revenue per unit water appliedResource /Energy Economics and Policy,

Modelling South African grain farmers’ preferences to adopt derivative contracts using discrete choice models

This paper applies a discrete choice model to determine specific characteristics that influence South African grain farmers’ preferences to hedge against uncertainties. This is the first empirical study on South African grain producers’ preferences to adopt derivative contracting and is based on the survey data of Grain South Africa for 2006. With the application of separate binary logit models for each major grain commodity, this paper establishes that different grain farmers are significantly heterogeneous. The results also show that grain farmers’ preferences to adopt derivative contracting are mostly influenced by the farmers’ prediction of daily grain prices and trends, farm size and various geographic characteristics. From a policy perspective it has been indicated that food and income insecurity will be reduced if farmers can adopt derivative contracting at large scale since it will enable the producers to produce staple food on a continuous basis at a relatively profitable level.Discrete choice models, micro-analysis of farmers, agricultural markets and marketing,

An assessment of the potential economic impacts of the invasive polyphagous shot hole borer (Coleoptera: Curculionidae) in South Africa

Studies addressing the economic impacts of invasive alien species are biased towards ex-post assessments of the costs and benefits of control options, but ex-ante assessments are also required to deal with potentially damaging invaders. The polyphagous shot hole borer Euwallacea fornicatus (Coleoptera: Curculionidae) is a recent and potentially damaging introduction to South Africa. We assessed the potential impact of this beetle by working across economic and biological disciplines and developing a simulation model that included dynamic mutualistic relations between the beetle and its symbiotic fungus. We modeled the potential growth in beetle populations and their effect on the net present cost of damage to natural forests, urban trees, commercial forestry, and the avocado industry over 10 yr. We modeled high, baseline, and low scenarios using discount rates of 8, 6, and 4%, and a plausible range of costs and mortality rates. Models predicted steady growth in the beetle and fungus populations, leading to average declines in tree populations of between 3.5 and 15.5% over 10 yr. The predicted net present cost was 18.45 billion international dollars (Int. $), or about 0.66$2.7 billion to $164 billion for low and high scenarios). Most of the costs are for the removal of urban trees that die as a result of the beetle and its fungal symbiont, as has been found in other regions. We conclude that an ex-ante economic assessment system dynamics model can be useful for informing national strategies on invasive alien species management.The Department of Science and Innovation-National Research Foundation (DSI-NRF) Centre of Excellence for Invasion Biology and the Centre for Biological Control at Rhodes University as well as the Oppenheimer Memorial Trust and the Millennium Trust.https://academic.oup.com/jeehj2023BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog

Are Socioeconomic Benefits of Restoration Adequately Quantified? A Meta-analysis of Recent Papers (2000–2008) in Restoration Ecology and 12 Other Scientific Journals. Restoration Ecology

Many ecosystems have been transformed, or degraded by human use, and restoration offers an opportunity to recover services and benefits, not to mention intrinsic values. We assessed whether restoration scientists and practitioners use their projects to demonstrate the benefits restoration can provide in their peer-reviewed publications. We evaluated a sample of the academic literature to determine whether links are made explicit between ecological restoration, society, and public policy related to natural capital. We analyzed 1,582 peer-reviewed papers dealing with ecological restoration published between 1 January 2000 and 30 September 2008 in 13 leading scientific journals. As selection criterion, we considered papers that contained either “restoration” or “rehabilitation” in their title, abstract, or keywords. Furthermore, as one-third of the papers were published in Restoration Ecology, we used that journal as a reference for comparison with all the other journals. We readily acknowledge that aquatic ecosystems are under-represented, and that the largely inaccessible gray literature was ignored. Within these constraints, we found clear evidence that restoration practitioners are failing to signal links between ecological restoration, society, and policy, and are underselling the evidence of benefits of restoration as a worthwhile investment for society. We discuss this assertion and illustrate it with samples of our findings—with regards to (1) the geographical and institutional affiliations of authors; (2) the choice of ecosystems studied, methods employed, monitoring schemes applied, and the spatial scale of studies; and (3) weak links to payments for ecosystem service setups, agriculture, and ramifications for public policy.The authors thank the South African Water Research Commission which provided financial support for this study, under contract K5/1803, The impact of reestablishing indigenous plants and restoring the natural landscape on sustainable rural employment and land productivity through payment for environmental services, awarded to ASSET Research (Pretoria)

A comparative assessment of the contribution of two different models for clearing invasive alien plants using grazing regimes in the Eastern Cape, South Africa

Invasive alien plants (IAPs) compromise the productive capability of a land parcel from both an economic and a biodiversity perspective. Given the magnitude of degradation and the benefits of landscape-scale restoration, a unified approach among stakeholders is required to upscale restoration efforts. Seeking such an approach, we compare the efficiencies of two restoration and land use models for the period 2014–2016. Model A is characterised by both mechanical and bioturbation as methods to control the IAPs combined with short duration, high-density rotational grazing. Model B uses mechanical and chemical methods to control IAPs, as well as a mixed rotational rest grazing system. We found that Model B’s unit cost was 47% higher than that of Model A (R13 747, compared with R9 327 ha−1). Model B is also less efficient with respect to the use of time and labour required to clear a hectare. We also note that seeking to simultaneously achieve dual objectives (e.g. ecological and social) using a single instrument, such as clearing IAPs, violates Tinbergen’s Golden Rule in Public Finance. By seeking efficiency on a single objective, e.g. with respect to ecological indicators, restoration will yield more benefits and impact more people for longer. Keywords: environmental management, natural resources, resource poolin

INTEGRATING THE NATURAL ENVIRONMENT AND MACROECONOMIC POLICY: RECOMMENDATIONS FOR SOUTH AFRICA

Macroeconomic policy should be guided by a long-term strategy based on the needs of the country. This is an essential message of the term ‘sustainable development’. It is, therefore, inevitable that the country’s natural and environmental resources should be considered when shaping such a policy. Current macroeconomic policies in South Africa have tended to ignore, rather than incorporate, these issues. This paper provides a framework for integrating environmental values into macroeconomic policy-making in South Africa. This is done by focusing on 1) the different theories on the linkage between the economy and the environment, 2) conceptualising the input of environmental values in the macroeconomic policy arena and 3) making recommendations for incorporating environmental factors into South African macroeconomic policy

A Critical Evaluation of the Capital Theory Approach to Sustainable Development

Irrigation farmers in the lower reaches of the Vaal and Riet Rivers are experiencing substantial yield reductions in certain crops and more profitable crops have been withdrawn from production, hypothesised, as a result of generally poor but especially fluctuating water quality. In this paper secondary data is used in a linear programming model to test this hypothesis by calculating the potential loss in farm level optimal returns. The model is static with a time frame of two production seasons. Linear crop-water quality production functions (Ayers & Westcot, 1983; adapted from Maas & Hoffmann, 1977) are used to calculate net returns for the eight most common crops grown. Results show optimal enterprise composition under various water quality situations. Leaching is justified financially and there is a strong motivation for a change in the current water pricing system. SALMOD (Salinity and Leaching Model for Optimal irrigation Development) is the Excel Solver model used to derive the preliminary results, but is currently being developed further in GAMS (General Algebraic Modelling System). Useful results have already been obtained on which this paper is based. The ultimate aim for SALMOD is a mathematical model using dynamic optimisation, simulation and risk modelling techniques to aid in whole farm and system level management decisions to ensure sustainable irrigation agriculture under stochastic river water quality conditions

The effect of rainfall variability on sustainable wheat production under no-till farming systems in the Swartland region, South Africa

Twenty years ago it was argued that rotational wheat production systems will reduce the economic risks to farmers and restore soil quality. Here we reflect on this assertion by analysing the evidence of a 12-year data window within a trial on a mixture of crop rotation systems at Langgewens Research Farm, South Africa. It was been found that production systems that include rotations with medics and/or medic-clover show some potential for improvement compared with wheat only, with a combination of the annual legume pasture with an added saltbush pasture showing the greatest improvement when taking into consideration the benefits from livestock production that are derived from pastures. Pastures are more resilient to changes in rainfall compared with wheat only. Planting pastures in alternate years also improves the yields from wheat, and this is beneficial in periods of low rainfall. Rotation systems on this farm that include lupin perform worse than the wheat-only model. Furthermore, when modelling the effect of drought on the system, the results of the multi- and rotation production systems actually improve