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Evaluating the social, biophysical, and financial implications of transitioning to conservation agriculture in a vegetable production system
Thesis (PhDAgric)--Stellenbosch University, 2026.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2026
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| _version_ | 1867614098225627136 |
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| access_status_str | Open Access |
| author | Andrews, Jade |
| author2 | Strauss, Johann |
| author_browse | Andrews, Jade Strauss, Johann |
| author_facet | Strauss, Johann Andrews, Jade |
| author_sort | Andrews, Jade |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhDAgric)--Stellenbosch University, 2026. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/135554 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:46:38.139Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/135554 Evaluating the social, biophysical, and financial implications of transitioning to conservation agriculture in a vegetable production system Andrews, Jade Strauss, Johann Hoffmann, Willem Swanepoel, Pieter Stellenbosch University. Faculty of AgriSciences. Dept. of Agronomy. Soils -- Health Sustainable agriculture -- South Africa -- Western Cape Agriculture -- Economic aspects Agriculture -- Environmental aspects -- South Africa -- Western Cape Vegetable gardening -- South Africa -- Western Cape Soil management Farm management -- South Africa -- Western Cape UCTD Thesis (PhDAgric)--Stellenbosch University, 2026. Andrews, J. 2026. Evaluating the social, biophysical, and financial implications of transitioning to conservation agriculture in a vegetable production system. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/df3e658e-38ae-4a1c-aa60-321a6c3399ea ENGLISH ABSTRACT: Much of South African croplands have faced severe soil degradation due to unsustainable farming practices, including intensive tillage, continuous monocultures, and agrochemical overuse. While conservation agriculture (CA) has improved soil health and crop yield, and decreased production costs in grain production systems in the Western Cape, South Africa, vegetables are predominantly produced in intensive systems. Although the adoption of CA in vegetable systems remains limited in South Africa, similar practices – such as cover crop-based reduced tillage (CCBRT) – have been integrated into existing organic vegetable systems across Europe. However, the results of these studies vary considerably, with some studies evaluating one or two CA principles, while others may include all three CA principles. This study therefore aimed to assess (i) farmer perceptions of CA; (ii) the soil health, (iii) agronomic effects, and financial implications of CA implementation in a vegetable system in Vredendal, South Africa. Interviews were conducted with grain and vegetable farmers in the Western Cape to explore the perceptions of CA amongst vegetable and grain farmers already using CA practices. The effects of three treatments (control, cover crop, and mulch) were determined on soil health indicators (microbial diversity and enzyme activity), nutrient stratification, soil compaction, crop yield, and weed seedbank diversity in Vredendal. The control treatment was a ‘business-as-usual’ approach, consisting of standard practices in the Vredendal region, while the cover crop treatment consisted of a mixture of barley (Hordeum vulgare), rye (Secale cereale) and bitter lupin (Lupinus angustifolius), and the mulch treatment consisted of wheat (Triticum aestivum) straw mulch applied to the soil surface. Each treatment was applied to two replicate plots within each of the three rotations, and this full rotation-treatment layout was implemented on all three farms. Finally, a financial simulation model based on standard accounting principles was used to determine the gross margins of each treatment and rotation combination on each of the three farms. Vegetable and grain farmers identified several motivations for CA adoption, requirements for the successful transition, benefits, important information sources, challenges, the perceived barriers to adoption, as well as areas for improvement. Overall, the effects of soil cover treatments varied between farms and indicators. While mulch treatments improved soil nutrient content and organic C, the effects on yield varied between farms and crops, and incurred the highest costs across all farms, demonstrating the weakest financial performance. These mixed results support several farmers’ arguments for context-specific application of CA. Although cover crop treatments incurred additional costs, these systems performed the best at Jondu, with mixed results at Sewester. However, yields required to reach breakeven far exceeded the typical yield for most crops, indicating that input costs outweighed the potential income. Given the unpredictability of vegetable market prices, reducing input costs remains the most practical approach to improve profitability. The limited treatment effects across soil biological indicators, and weed diversity, could be due to the short duration of CA adoption. Finally, this study demonstrated that treatments could also result in trade-offs between crops within a rotation that need to be carefully managed. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Doctoral 2026-04-01T10:39:20Z 2026-04-01T10:39:20Z 2026-03 Thesis https://scholar.sun.ac.za/handle/10019.1/135554 en Stellenbosch University x, 180 pages : illustrations, maps application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Soils -- Health Sustainable agriculture -- South Africa -- Western Cape Agriculture -- Economic aspects Agriculture -- Environmental aspects -- South Africa -- Western Cape Vegetable gardening -- South Africa -- Western Cape Soil management Farm management -- South Africa -- Western Cape UCTD Andrews, Jade Evaluating the social, biophysical, and financial implications of transitioning to conservation agriculture in a vegetable production system |
| title | Evaluating the social, biophysical, and financial implications of transitioning to conservation agriculture in a vegetable production system |
| title_full | Evaluating the social, biophysical, and financial implications of transitioning to conservation agriculture in a vegetable production system |
| title_fullStr | Evaluating the social, biophysical, and financial implications of transitioning to conservation agriculture in a vegetable production system |
| title_full_unstemmed | Evaluating the social, biophysical, and financial implications of transitioning to conservation agriculture in a vegetable production system |
| title_short | Evaluating the social, biophysical, and financial implications of transitioning to conservation agriculture in a vegetable production system |
| title_sort | evaluating the social biophysical and financial implications of transitioning to conservation agriculture in a vegetable production system |
| topic | Soils -- Health Sustainable agriculture -- South Africa -- Western Cape Agriculture -- Economic aspects Agriculture -- Environmental aspects -- South Africa -- Western Cape Vegetable gardening -- South Africa -- Western Cape Soil management Farm management -- South Africa -- Western Cape UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/135554 |
| work_keys_str_mv | AT andrewsjade evaluatingthesocialbiophysicalandfinancialimplicationsoftransitioningtoconservationagricultureinavegetableproductionsystem |