Thulasizwe Mkhabela - Academia.edu (original) (raw)

Papers by Thulasizwe Mkhabela

Journal of Plant Nutrition, Aug 1, 2006

This paper reviews the problems of soil fertility under small-scale crop production systems in Kw... more This paper reviews the problems of soil fertility under small-scale crop production systems in KwaZulu-Natal province in South Africa. The role of manure in maintaining and replenishing soil fertility for crop production and the fate of manure once applied to the soil are reviewed and discussed. Special emphasis is placed on cattle and chicken manure and the role that soil

Agrekon, Mar 1, 2002

This study employed the logit model to examine factors that influence the use of cattle and chick... more This study employed the logit model to examine factors that influence the use of cattle and chicken manure for managing soil fertility by surveying a random sample of 224 farm households in the Midlands of KwaZulu-Natal province, South Africa. The majority (87%) of the respondents were farming on communal land with an average farm size of 2.9 hectares. Sixty-three % of the farmers in the sample used manure to manage soil fertility in their fields. Cattle manure was used by 54% while chicken manure was used by 39% of the sample. Manure was readily available to 73% of the respondent farmers. The common method of applying manure was by a spreader. Some suggestions are made on strategies that could improve the efficiency of utilization of manure for soil fertility management in this agro ecosystem.

Southern African forestry journal, Jul 1, 2003

The purpose of the investigation was to examine current knowledge, by local people, of the agrofo... more The purpose of the investigation was to examine current knowledge, by local people, of the agroforestry roles and the economic importance that the Acacia karroo tree plays in the farming systems or small-scale farmers and game farming in the Dundee district in the KwaZulu-Natal Province. Interviews were conducted in 111 selected households and game farms using a rapid appraisal approach. Results showed that the entire sample population was aware of the beneficial roles played by Acacia karroo in the agroecosystem and had a least one tree in their homestead, field and/or grazing land. The roles identified by the respondents were: providing shelter to people and animals (98%), fodder for game and livestock (96%), fuel (93%), indicator of ‘sweet veld’ good soils and good grazing (87%), controlling soil erosion (71%), indicator of water in arid areas (37%), maintaining soil fertility and productivity (36%), dependence of certain butterfly larvae species and birds that feed on these larva (8%) and the USe of wood ash to ameliorate soil acidity (4%). Despite the benefits of A. karroo on farms and nature reserves being well appreciated, the deliberate utilisation of this tree for agroforestry purposes is minimal. Due to the prevailing soil acidity problems and extensive land degradation, it is suggested that the tree has potential in agroforestry to change and improve the sustainability and profitability of both agriculture and ecotourism through game farming in the area. It is also acknowledged that for any land use to expand in a sustainable manner, appropriate research and development is imperative. Some suggestions are made on future research.

Agrekon, Mar 1, 2003

The economic feasibility of using composted manure from KwaZulu-Natal midlands feedlots in combin... more The economic feasibility of using composted manure from KwaZulu-Natal midlands feedlots in combination with commercial N in production of dryland grain maize [Zea mays (L.)] was evaluated. Effective disposal of large quantities of manure from large scale feedlots is a concern. Yield data from Cedara experiment station were used to estimate a quadratic production function where maize grain yield is a function of manure and commercial fertiliser N application rates. Four rates of commercial N (0, 50, 100 and 200 kg ha-1) and five rates of composted feedlot manure (0, 5, 10, 20 and 30 t ha-1 , as is basis) in a factorial arrangement were applied to dryland maize. The production function estimate was used to determine the combination of composted manure and commercial N, which maximized net returns. The results suggest that a compost application rate of 15 t ha-1 with 20 kg ha-1 of commercial N would be economically feasible when the price of commercial N, including application charges, is R4.50 kg-1 and the price of compost R77.20 t-1. Once the price of compost reaches R95.00 t-1 compost use is no longer economically feasible. 1.

Studies in Economics and Econometrics, Dec 1, 2006

Abstract The work reported here used a short-term specification of the symmetric generalised McFa... more Abstract The work reported here used a short-term specification of the symmetric generalised McFadden (SGM) cost function capable of incorporating quasi-fixed factors and variable returns. Temporary equilibrium and scale economies were investigated while maintaining the consistency of the estimated model with microeconomic theory and approximation properties. The methodology also makes use of a two-step procedure to estimate first the technology parameters and then time-varying efficiency at farm level. No distributional assumptions are required on efficiency as a fixed effect model was considered. A balanced panel of dairy farms in KwaZulu-Natal during the years from 1990 to 2002 was used for the analyses. The results show a rigid productive structure during the study period. In addition, milk producers in KwaZulu-Natal were found to exhibit considerable excess capacity and rather low input technical efficiency.

Studies in Economics and Econometrics, Apr 1, 2006

Abstract Since none of the production frontier models used in empirical analyses of production ef... more Abstract Since none of the production frontier models used in empirical analyses of production efficiency is without its limitations, it is very important to make a careful choice of model. The different types of production frontier models all have their strengths and weaknesses. Findings of previous studies on sensitivity of technical efficiency estimates by different methods are mixed thus more research comparing technical efficiency measurements from alternative models is needed in order to determine the robustness of estimates from a particular model. The present study analysed the extent to which DEA, econometric stochastic production frontier and the statistical deterministic frontier differ from one another in measuring technical efficiency using the KwaZulu-Natal midlands dairy industry. The general findings from this study indicate that estimates of technical efficiencies of individual dairy farms, and therefore the mean technical efficiency of the KZN dairy industry, are sensitive to the choice of production frontier estimation method.

Southern Forests, Jul 1, 2003

The purpose of the investigation was to examine current knowledge, by local people, of the agrofo... more The purpose of the investigation was to examine current knowledge, by local people, of the agroforestry roles and the economic importance that the Acacia karroo tree plays in the farming systems or small-scale farmers and game farming in the Dundee district in the KwaZulu-Natal Province. Interviews were conducted in 111 selected households and game farms using a rapid appraisal approach. Results showed that the entire sample population was aware of the beneficial roles played by Acacia karroo in the agroecosystem and had a least one tree in their homestead, field and/or grazing land. The roles identified by the respondents were: providing shelter to people and animals (98%), fodder for game and livestock (96%), fuel (93%), indicator of ‘sweet veld’ good soils and good grazing (87%), controlling soil erosion (71%), indicator of water in arid areas (37%), maintaining soil fertility and productivity (36%), dependence of certain butterfly larvae species and birds that feed on these larva (8%) and the USe of wood ash to ameliorate soil acidity (4%). Despite the benefits of A. karroo on farms and nature reserves being well appreciated, the deliberate utilisation of this tree for agroforestry purposes is minimal. Due to the prevailing soil acidity problems and extensive land degradation, it is suggested that the tree has potential in agroforestry to change and improve the sustainability and profitability of both agriculture and ecotourism through game farming in the area. It is also acknowledged that for any land use to expand in a sustainable manner, appropriate research and development is imperative. Some suggestions are made on future research.

Agrekon, Jun 1, 2002

Considerable literature has linked the increasing concentration of agricultural production to sev... more Considerable literature has linked the increasing concentration of agricultural production to severe ecological problems. There is an argument that large-scale farmers are less concerned about the environment and, therefore, less likely than smallscale farmers to employ environmentally sound methods and practices. However, this paper advances an alternative hypothesis predicting that small-scale farmers are less able to preserve the environment than large-scale farmers because of environmental and institutional constraints such as farming on highly erodable and marginal soils. To test this hypothesis, the relationship between farm size and estimated soil loss using data obtained from a random sample of farmers in a KwaZulu-Natal midlands community was examined. Large farms were found to have lower estimated soil loss than small farms, mainly because the land farmed had less potential for erosion. The implications of these findings for developing an effective soil conservation policy are discussed The differential productivity of farmland must be represented in any analysis of the changing structure of agriculture and the efficiency of large and small farms. The most productive farmland in this country has a relatively low soil-erosion potential and lends itself to capital-intensive agricultural production. Capital-intensive agriculture is not attracted to the marginal land that has higher erosion potential. Marginal lands are, however, the most accessible and affordable for smaller farmers. Soil erosion, then, is a problem of small-farm agriculture, not capital-intensive agriculture.

UNISWA Journal of Agriculture, 1994

Studies in Economics and Econometrics, 2010

TS Mkhabela, my co-supervisor for his guidance, support and encouragement throughout the study an... more TS Mkhabela, my co-supervisor for his guidance, support and encouragement throughout the study and sharing his econometrics skills. Prof. DG Nel for his outstanding assistance and sharing his research expertise in statistical analysis. My mum, dad and siblings for their love, support and patience. All the cooperatives who completed the questionnaire. Debbie Wait of SAWIS for her provision of necessary information whenever needed. Twagira ME, Mugadza P, Kisengese N and Bianca M for their friendship, encouragement and valuable moral support. v TABLE OF CONTENTS Declaration i Summary ii Opsomming iii Acknowledgements iv Table of Contents v List of Tables x List of Figures xiii List of Appendices xiv List of Abbreviations xv CHAPTER 1 INTRODUCTION 1.1 BACKGROUND TO THE STUDY 1.2 STATEMENT OF THE PROBLEM

Soil & Tillage Research, Oct 1, 2001

An assessment of changes in soil properties associated with land-use and management practices is ... more An assessment of changes in soil properties associated with land-use and management practices is vital for the selection and establishment of appropriate sustainable practices under different agroecosystems. This study compared soil properties between land located on an abandoned kraal site (KS), under fallow (FL) and one that was continuously cropped to maize (CC) for over 12 years. Aggregation and aggregate stability as measured by both dry and wet sieving showed large differences between land-use systems. The soil under CC had a higher proportion (26.4%) of micro aggregates (<0.25 mm) compared with that of FL (10.1%) and KS (6.9%). The dry mean weight diameter (DMWD) was larger in KS (3.03 mm) than in FL (2.17 mm) and CC (1.38 mm). Soil aggregates in CC were the least stable with a wet mean weight diameter (WMWD) of (1.61 mm) compared with those of FL (2.18 mm) and KS (2.89 mm). Reduced stability of aggregates in CC is likely due to the lower organic carbon content of soil in this land-use (1.7%) compared with that of FL (2.5%) and KS (3.2%). The soil under KS had lower bulk density (BD), penetration resistance (PR) and aggregate tensile strength (ATS) than that of FL and CC. Soil moisture content (MC) and available water capacity (AWC) showed an opposite trend. The soil in KS had a higher concentration of total N (TN), available P and exchangeable K, Ca, Mg and Zn. Soil on CC, on the other hand, had a higher concentration of Mn than that from FS and KS possibly because of its acidic nature. There were signi®cant strong correlations between soil organic carbon and BD (À0.86 ÃÃÃ), PR (À0.61 Ã), MC (0.82 ÃÃ), ATS (À0.62 Ã), WSA (0.79 ÃÃÃ), AWC (0.91 ÃÃÃ), pH (À0.61 ÃÃ) and TN (0.76 ÃÃÃ). Grain yields of maize were highest in KS followed by FL and least in CC. The high yields were attributed to improved soil properties in plots of KS compared with both FL and CC. In conclusion, the ®ndings suggested that organic matter had a major in¯uence on soil properties and fertility.

The South African Journal of Plant and Soil, 2002

The influence of manure ingestion by larvae of Oryctes boas on casting and cast properties was st... more The influence of manure ingestion by larvae of Oryctes boas on casting and cast properties was studied in an incubation microcosm experiment. Inoculation of manure with larvae of O. boas significantly reduced the proportion of large (>8.0 mm) aggregates from 81 % in non-cast manure to 3.5% in cast manure. In turn, the larvae converted the majority (92.7%) of the aggregate sizes into the 2-8 mm range compared with 14.5% for the uninoculated manure. Mean weight diameters of dry aggregates were 5.34 mm and 18.45 mm for the treatments with and without O. boas, respectively. The casts also had significantly higher proportions of water stable macro-aggregates than non-cast manure (99.8 vs 90.2%). The higher stability of casts corresponded with their higher tensile strength (769 vs 408 kPa) and bulk density (1.58 vs 1.07 Mg m• 3) compared with the non-cast manure. Chemically, the production of casts from manure resulted in a pH shift towards neutrality and significant increases in the concentration of plant nutrient elements (N, P, Ca, K and Mg) compared to non-cast manure. The results suggest that the larvae of O. boas can play an important role as soil ecosystem engineers and provides a promising option for converting organic wastes into strongly aggregated granular compost.

Bioresource Technology, Oct 1, 2002

There are about 130,000 hectares of land in South Africa that have been under black wattle planta... more There are about 130,000 hectares of land in South Africa that have been under black wattle plantation for a long time and whose soils have become more acidic than those from contiguous land without the tree. This incubation study investigated the effectiveness of lime, chicken manure and leaf litter ash to ameliorate the soil acidity. Lime and chicken manure were applied in pots at rates equivalent to 0, 5, 10 and 20 Mg ha À1 while ash was applied at 0, 3 and 5 Mg ha À1. In comparison to the control, the application of all the three amendments caused significant increases in soil pH KCL (4.1-5.6) and reduced the exchangeable acidity. The liming effectiveness of the amendments varied with rate and type of amendment and were in the order: lime > chicken manure > ash. A similar trend was evident in the concentration of exchangeable bases (Ca, Mg and K) in the soil. The effectiveness of ash and chicken manure as liming material was 0.12 and 0.26 respectively compared to lime. The difference in liming effect between ash and chicken manure was related to their alkalinity concentration. It was concluded that both amendments have the potential to be used as liming materials and merit further field evaluation.

The simulation results presented in this paper provided nuanced policy options for redistribution... more The simulation results presented in this paper provided nuanced policy options for redistribution in South Africa in the face of the looming expropriation of land without compensation. The simulation done through Computable General Equilibrium approach using the modified University of Pretoria General Equilibrium Model (UPGEM) which is solved using a GEMPACK solution software. The simulation revealed that there will be adjustment costs regardless of the option(s) chosen. The Inclusive Scenario came up as the most suitable policy option in terms of minimal adjustment costs and allowing the sector to continue to grow, albeit at a lower rate compared to the status quo.

Cogent Social Sciences, Oct 22, 2022

Transforming Agriculture in Southern Africa, 2019

Transforming Agriculture in Southern Africa, 2019

DECLARATION By submitting this dissertation electronically, I declare that the entirety of the wo... more DECLARATION By submitting this dissertation electronically, I declare that the entirety of the work contained therein is my own, original work, that I am the authorship owner thereof (unless to the extent explicitly otherwise stated) and that I have not previously in its entirety or in part submitted it

Transforming Agriculture in Southern Africa, 2019

Journal of Plant Nutrition, Aug 1, 2006

This paper reviews the problems of soil fertility under small-scale crop production systems in Kw... more This paper reviews the problems of soil fertility under small-scale crop production systems in KwaZulu-Natal province in South Africa. The role of manure in maintaining and replenishing soil fertility for crop production and the fate of manure once applied to the soil are reviewed and discussed. Special emphasis is placed on cattle and chicken manure and the role that soil

Agrekon, Mar 1, 2002

This study employed the logit model to examine factors that influence the use of cattle and chick... more This study employed the logit model to examine factors that influence the use of cattle and chicken manure for managing soil fertility by surveying a random sample of 224 farm households in the Midlands of KwaZulu-Natal province, South Africa. The majority (87%) of the respondents were farming on communal land with an average farm size of 2.9 hectares. Sixty-three % of the farmers in the sample used manure to manage soil fertility in their fields. Cattle manure was used by 54% while chicken manure was used by 39% of the sample. Manure was readily available to 73% of the respondent farmers. The common method of applying manure was by a spreader. Some suggestions are made on strategies that could improve the efficiency of utilization of manure for soil fertility management in this agro ecosystem.

Southern African forestry journal, Jul 1, 2003

The purpose of the investigation was to examine current knowledge, by local people, of the agrofo... more The purpose of the investigation was to examine current knowledge, by local people, of the agroforestry roles and the economic importance that the Acacia karroo tree plays in the farming systems or small-scale farmers and game farming in the Dundee district in the KwaZulu-Natal Province. Interviews were conducted in 111 selected households and game farms using a rapid appraisal approach. Results showed that the entire sample population was aware of the beneficial roles played by Acacia karroo in the agroecosystem and had a least one tree in their homestead, field and/or grazing land. The roles identified by the respondents were: providing shelter to people and animals (98%), fodder for game and livestock (96%), fuel (93%), indicator of ‘sweet veld’ good soils and good grazing (87%), controlling soil erosion (71%), indicator of water in arid areas (37%), maintaining soil fertility and productivity (36%), dependence of certain butterfly larvae species and birds that feed on these larva (8%) and the USe of wood ash to ameliorate soil acidity (4%). Despite the benefits of A. karroo on farms and nature reserves being well appreciated, the deliberate utilisation of this tree for agroforestry purposes is minimal. Due to the prevailing soil acidity problems and extensive land degradation, it is suggested that the tree has potential in agroforestry to change and improve the sustainability and profitability of both agriculture and ecotourism through game farming in the area. It is also acknowledged that for any land use to expand in a sustainable manner, appropriate research and development is imperative. Some suggestions are made on future research.

Agrekon, Mar 1, 2003

The economic feasibility of using composted manure from KwaZulu-Natal midlands feedlots in combin... more The economic feasibility of using composted manure from KwaZulu-Natal midlands feedlots in combination with commercial N in production of dryland grain maize [Zea mays (L.)] was evaluated. Effective disposal of large quantities of manure from large scale feedlots is a concern. Yield data from Cedara experiment station were used to estimate a quadratic production function where maize grain yield is a function of manure and commercial fertiliser N application rates. Four rates of commercial N (0, 50, 100 and 200 kg ha-1) and five rates of composted feedlot manure (0, 5, 10, 20 and 30 t ha-1 , as is basis) in a factorial arrangement were applied to dryland maize. The production function estimate was used to determine the combination of composted manure and commercial N, which maximized net returns. The results suggest that a compost application rate of 15 t ha-1 with 20 kg ha-1 of commercial N would be economically feasible when the price of commercial N, including application charges, is R4.50 kg-1 and the price of compost R77.20 t-1. Once the price of compost reaches R95.00 t-1 compost use is no longer economically feasible. 1.

Studies in Economics and Econometrics, Dec 1, 2006

Abstract The work reported here used a short-term specification of the symmetric generalised McFa... more Abstract The work reported here used a short-term specification of the symmetric generalised McFadden (SGM) cost function capable of incorporating quasi-fixed factors and variable returns. Temporary equilibrium and scale economies were investigated while maintaining the consistency of the estimated model with microeconomic theory and approximation properties. The methodology also makes use of a two-step procedure to estimate first the technology parameters and then time-varying efficiency at farm level. No distributional assumptions are required on efficiency as a fixed effect model was considered. A balanced panel of dairy farms in KwaZulu-Natal during the years from 1990 to 2002 was used for the analyses. The results show a rigid productive structure during the study period. In addition, milk producers in KwaZulu-Natal were found to exhibit considerable excess capacity and rather low input technical efficiency.

Studies in Economics and Econometrics, Apr 1, 2006

Abstract Since none of the production frontier models used in empirical analyses of production ef... more Abstract Since none of the production frontier models used in empirical analyses of production efficiency is without its limitations, it is very important to make a careful choice of model. The different types of production frontier models all have their strengths and weaknesses. Findings of previous studies on sensitivity of technical efficiency estimates by different methods are mixed thus more research comparing technical efficiency measurements from alternative models is needed in order to determine the robustness of estimates from a particular model. The present study analysed the extent to which DEA, econometric stochastic production frontier and the statistical deterministic frontier differ from one another in measuring technical efficiency using the KwaZulu-Natal midlands dairy industry. The general findings from this study indicate that estimates of technical efficiencies of individual dairy farms, and therefore the mean technical efficiency of the KZN dairy industry, are sensitive to the choice of production frontier estimation method.

Southern Forests, Jul 1, 2003

The purpose of the investigation was to examine current knowledge, by local people, of the agrofo... more The purpose of the investigation was to examine current knowledge, by local people, of the agroforestry roles and the economic importance that the Acacia karroo tree plays in the farming systems or small-scale farmers and game farming in the Dundee district in the KwaZulu-Natal Province. Interviews were conducted in 111 selected households and game farms using a rapid appraisal approach. Results showed that the entire sample population was aware of the beneficial roles played by Acacia karroo in the agroecosystem and had a least one tree in their homestead, field and/or grazing land. The roles identified by the respondents were: providing shelter to people and animals (98%), fodder for game and livestock (96%), fuel (93%), indicator of ‘sweet veld’ good soils and good grazing (87%), controlling soil erosion (71%), indicator of water in arid areas (37%), maintaining soil fertility and productivity (36%), dependence of certain butterfly larvae species and birds that feed on these larva (8%) and the USe of wood ash to ameliorate soil acidity (4%). Despite the benefits of A. karroo on farms and nature reserves being well appreciated, the deliberate utilisation of this tree for agroforestry purposes is minimal. Due to the prevailing soil acidity problems and extensive land degradation, it is suggested that the tree has potential in agroforestry to change and improve the sustainability and profitability of both agriculture and ecotourism through game farming in the area. It is also acknowledged that for any land use to expand in a sustainable manner, appropriate research and development is imperative. Some suggestions are made on future research.

Agrekon, Jun 1, 2002

Considerable literature has linked the increasing concentration of agricultural production to sev... more Considerable literature has linked the increasing concentration of agricultural production to severe ecological problems. There is an argument that large-scale farmers are less concerned about the environment and, therefore, less likely than smallscale farmers to employ environmentally sound methods and practices. However, this paper advances an alternative hypothesis predicting that small-scale farmers are less able to preserve the environment than large-scale farmers because of environmental and institutional constraints such as farming on highly erodable and marginal soils. To test this hypothesis, the relationship between farm size and estimated soil loss using data obtained from a random sample of farmers in a KwaZulu-Natal midlands community was examined. Large farms were found to have lower estimated soil loss than small farms, mainly because the land farmed had less potential for erosion. The implications of these findings for developing an effective soil conservation policy are discussed The differential productivity of farmland must be represented in any analysis of the changing structure of agriculture and the efficiency of large and small farms. The most productive farmland in this country has a relatively low soil-erosion potential and lends itself to capital-intensive agricultural production. Capital-intensive agriculture is not attracted to the marginal land that has higher erosion potential. Marginal lands are, however, the most accessible and affordable for smaller farmers. Soil erosion, then, is a problem of small-farm agriculture, not capital-intensive agriculture.

UNISWA Journal of Agriculture, 1994

Studies in Economics and Econometrics, 2010

TS Mkhabela, my co-supervisor for his guidance, support and encouragement throughout the study an... more TS Mkhabela, my co-supervisor for his guidance, support and encouragement throughout the study and sharing his econometrics skills. Prof. DG Nel for his outstanding assistance and sharing his research expertise in statistical analysis. My mum, dad and siblings for their love, support and patience. All the cooperatives who completed the questionnaire. Debbie Wait of SAWIS for her provision of necessary information whenever needed. Twagira ME, Mugadza P, Kisengese N and Bianca M for their friendship, encouragement and valuable moral support. v TABLE OF CONTENTS Declaration i Summary ii Opsomming iii Acknowledgements iv Table of Contents v List of Tables x List of Figures xiii List of Appendices xiv List of Abbreviations xv CHAPTER 1 INTRODUCTION 1.1 BACKGROUND TO THE STUDY 1.2 STATEMENT OF THE PROBLEM

Soil & Tillage Research, Oct 1, 2001

An assessment of changes in soil properties associated with land-use and management practices is ... more An assessment of changes in soil properties associated with land-use and management practices is vital for the selection and establishment of appropriate sustainable practices under different agroecosystems. This study compared soil properties between land located on an abandoned kraal site (KS), under fallow (FL) and one that was continuously cropped to maize (CC) for over 12 years. Aggregation and aggregate stability as measured by both dry and wet sieving showed large differences between land-use systems. The soil under CC had a higher proportion (26.4%) of micro aggregates (<0.25 mm) compared with that of FL (10.1%) and KS (6.9%). The dry mean weight diameter (DMWD) was larger in KS (3.03 mm) than in FL (2.17 mm) and CC (1.38 mm). Soil aggregates in CC were the least stable with a wet mean weight diameter (WMWD) of (1.61 mm) compared with those of FL (2.18 mm) and KS (2.89 mm). Reduced stability of aggregates in CC is likely due to the lower organic carbon content of soil in this land-use (1.7%) compared with that of FL (2.5%) and KS (3.2%). The soil under KS had lower bulk density (BD), penetration resistance (PR) and aggregate tensile strength (ATS) than that of FL and CC. Soil moisture content (MC) and available water capacity (AWC) showed an opposite trend. The soil in KS had a higher concentration of total N (TN), available P and exchangeable K, Ca, Mg and Zn. Soil on CC, on the other hand, had a higher concentration of Mn than that from FS and KS possibly because of its acidic nature. There were signi®cant strong correlations between soil organic carbon and BD (À0.86 ÃÃÃ), PR (À0.61 Ã), MC (0.82 ÃÃ), ATS (À0.62 Ã), WSA (0.79 ÃÃÃ), AWC (0.91 ÃÃÃ), pH (À0.61 ÃÃ) and TN (0.76 ÃÃÃ). Grain yields of maize were highest in KS followed by FL and least in CC. The high yields were attributed to improved soil properties in plots of KS compared with both FL and CC. In conclusion, the ®ndings suggested that organic matter had a major in¯uence on soil properties and fertility.

The South African Journal of Plant and Soil, 2002

The influence of manure ingestion by larvae of Oryctes boas on casting and cast properties was st... more The influence of manure ingestion by larvae of Oryctes boas on casting and cast properties was studied in an incubation microcosm experiment. Inoculation of manure with larvae of O. boas significantly reduced the proportion of large (>8.0 mm) aggregates from 81 % in non-cast manure to 3.5% in cast manure. In turn, the larvae converted the majority (92.7%) of the aggregate sizes into the 2-8 mm range compared with 14.5% for the uninoculated manure. Mean weight diameters of dry aggregates were 5.34 mm and 18.45 mm for the treatments with and without O. boas, respectively. The casts also had significantly higher proportions of water stable macro-aggregates than non-cast manure (99.8 vs 90.2%). The higher stability of casts corresponded with their higher tensile strength (769 vs 408 kPa) and bulk density (1.58 vs 1.07 Mg m• 3) compared with the non-cast manure. Chemically, the production of casts from manure resulted in a pH shift towards neutrality and significant increases in the concentration of plant nutrient elements (N, P, Ca, K and Mg) compared to non-cast manure. The results suggest that the larvae of O. boas can play an important role as soil ecosystem engineers and provides a promising option for converting organic wastes into strongly aggregated granular compost.

Bioresource Technology, Oct 1, 2002

There are about 130,000 hectares of land in South Africa that have been under black wattle planta... more There are about 130,000 hectares of land in South Africa that have been under black wattle plantation for a long time and whose soils have become more acidic than those from contiguous land without the tree. This incubation study investigated the effectiveness of lime, chicken manure and leaf litter ash to ameliorate the soil acidity. Lime and chicken manure were applied in pots at rates equivalent to 0, 5, 10 and 20 Mg ha À1 while ash was applied at 0, 3 and 5 Mg ha À1. In comparison to the control, the application of all the three amendments caused significant increases in soil pH KCL (4.1-5.6) and reduced the exchangeable acidity. The liming effectiveness of the amendments varied with rate and type of amendment and were in the order: lime > chicken manure > ash. A similar trend was evident in the concentration of exchangeable bases (Ca, Mg and K) in the soil. The effectiveness of ash and chicken manure as liming material was 0.12 and 0.26 respectively compared to lime. The difference in liming effect between ash and chicken manure was related to their alkalinity concentration. It was concluded that both amendments have the potential to be used as liming materials and merit further field evaluation.

The simulation results presented in this paper provided nuanced policy options for redistribution... more The simulation results presented in this paper provided nuanced policy options for redistribution in South Africa in the face of the looming expropriation of land without compensation. The simulation done through Computable General Equilibrium approach using the modified University of Pretoria General Equilibrium Model (UPGEM) which is solved using a GEMPACK solution software. The simulation revealed that there will be adjustment costs regardless of the option(s) chosen. The Inclusive Scenario came up as the most suitable policy option in terms of minimal adjustment costs and allowing the sector to continue to grow, albeit at a lower rate compared to the status quo.

Cogent Social Sciences, Oct 22, 2022

Transforming Agriculture in Southern Africa, 2019

Transforming Agriculture in Southern Africa, 2019

DECLARATION By submitting this dissertation electronically, I declare that the entirety of the wo... more DECLARATION By submitting this dissertation electronically, I declare that the entirety of the work contained therein is my own, original work, that I am the authorship owner thereof (unless to the extent explicitly otherwise stated) and that I have not previously in its entirety or in part submitted it

Transforming Agriculture in Southern Africa, 2019