Evaluation and mapping of the spatial variability of soil fertility at Zanyokwe Irrigation Scheme in the Eastern Cape, South Africa
- Authors: Manyevere, Alen
- Date: 2010
- Subjects: Soil surveys -- South Africa -- Eastern Cape , Irrigation farming -- South Africa , Soil fertility -- South Africa -- Eastern Cape , Soils -- Analysis , Soils -- Testing , Crop yields , Soils Classification
- Language: English
- Type: Thesis , Masters , MSc Agric (Soil Science)
- Identifier: vital:11176 , http://hdl.handle.net/10353/d1001019 , Soil surveys -- South Africa -- Eastern Cape , Irrigation farming -- South Africa , Soil fertility -- South Africa -- Eastern Cape , Soils -- Analysis , Soils -- Testing , Crop yields , Soils Classification
- Full Text: false
- Date Issued: 2010
- Authors: Manyevere, Alen
- Date: 2010
- Subjects: Soil surveys -- South Africa -- Eastern Cape , Irrigation farming -- South Africa , Soil fertility -- South Africa -- Eastern Cape , Soils -- Analysis , Soils -- Testing , Crop yields , Soils Classification
- Language: English
- Type: Thesis , Masters , MSc Agric (Soil Science)
- Identifier: vital:11176 , http://hdl.handle.net/10353/d1001019 , Soil surveys -- South Africa -- Eastern Cape , Irrigation farming -- South Africa , Soil fertility -- South Africa -- Eastern Cape , Soils -- Analysis , Soils -- Testing , Crop yields , Soils Classification
- Full Text: false
- Date Issued: 2010
The influence of rain-fed organic and conventional crop farming systems on soil water content and water use efficiency in South Africa’s Southern Cape
- Authors: Eckert, Catherine Jessica
- Date: 2025-04
- Subjects: Soil fertility -- South Africa , Crop yields , Agricultural systems -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/75650 , vital:79978
- Description: In water-scarce regions, where droughts are frequent, efficient water use in agriculture is critical, especially in the context of climate change. This research investigates the effects of rain-fed organic and conventional monocrop and rotated crop farming practices on soil water retention and water use efficiency (WUE) at the Nelson Mandela Comparative Organic Farming Systems Research Trials, located at Nelson Mandela University’s George Campus in South Africa’s Southern Cape. The study compares the WUE of organic and conventional monocrop cabbage, as well as organic and conventional rotated cabbage, sweet potatoes, and cowpeas across four growing seasons (2014-15, 2015-16, 2016-17, 2017-18). Soil water content (SWC) was monitored during the 2016-17 and 2017- 18 seasons, and a fallow period in 2019-20 to evaluate the residual effects of organic and conventional treatments. HYDRUS-1D was used to model SWC in the 2016-17 and 2017-18 seasons, providing insights into transpiration, evaporation, percolation, and water storage as percentages of total rainfall. The findings indicate that organic farming generally enhances soil water retention in the upper soil layers, showing significant differences across multiple seasons. In monocrops, the organic system consistently exhibited higher SWC up to 70 cm, while the conventional system retained more water at deeper soil depths. Rotated crops showed variable results, with the organic system often outperforming the conventional one at shallower depths. WUE results revealed that conventional monocrop cabbage typically achieved the highest WUE, particularly in wetter seasons, whereas organic systems excelled in drier conditions. For rotated crops, conventional systems generally exhibited better WUE, though organic rotations performed better under drought conditions. The HYDRUS-1D simulations confirmed that organic systems had superior water retention and less negative change in water storage, supporting better WUE and productivity during drier periods. Moreover, organic rotated sweet potatoes consistently demonstrated superior WUE compared to their conventional counterparts, underscoring the importance of crop selection in organic farming systems. These findings suggest that organic practices, by improving soil water retention, enhance crop resilience and contribute to sustainable agricultural productivity in water-limited environments. Improving soil water retention through organic farming practices is a viable strategy to enhance crop production in water-scarce regions, contributing to food security, water conservation, and the overall resilience of agricultural systems. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2025
- Full Text:
- Date Issued: 2025-04
- Authors: Eckert, Catherine Jessica
- Date: 2025-04
- Subjects: Soil fertility -- South Africa , Crop yields , Agricultural systems -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/75650 , vital:79978
- Description: In water-scarce regions, where droughts are frequent, efficient water use in agriculture is critical, especially in the context of climate change. This research investigates the effects of rain-fed organic and conventional monocrop and rotated crop farming practices on soil water retention and water use efficiency (WUE) at the Nelson Mandela Comparative Organic Farming Systems Research Trials, located at Nelson Mandela University’s George Campus in South Africa’s Southern Cape. The study compares the WUE of organic and conventional monocrop cabbage, as well as organic and conventional rotated cabbage, sweet potatoes, and cowpeas across four growing seasons (2014-15, 2015-16, 2016-17, 2017-18). Soil water content (SWC) was monitored during the 2016-17 and 2017- 18 seasons, and a fallow period in 2019-20 to evaluate the residual effects of organic and conventional treatments. HYDRUS-1D was used to model SWC in the 2016-17 and 2017-18 seasons, providing insights into transpiration, evaporation, percolation, and water storage as percentages of total rainfall. The findings indicate that organic farming generally enhances soil water retention in the upper soil layers, showing significant differences across multiple seasons. In monocrops, the organic system consistently exhibited higher SWC up to 70 cm, while the conventional system retained more water at deeper soil depths. Rotated crops showed variable results, with the organic system often outperforming the conventional one at shallower depths. WUE results revealed that conventional monocrop cabbage typically achieved the highest WUE, particularly in wetter seasons, whereas organic systems excelled in drier conditions. For rotated crops, conventional systems generally exhibited better WUE, though organic rotations performed better under drought conditions. The HYDRUS-1D simulations confirmed that organic systems had superior water retention and less negative change in water storage, supporting better WUE and productivity during drier periods. Moreover, organic rotated sweet potatoes consistently demonstrated superior WUE compared to their conventional counterparts, underscoring the importance of crop selection in organic farming systems. These findings suggest that organic practices, by improving soil water retention, enhance crop resilience and contribute to sustainable agricultural productivity in water-limited environments. Improving soil water retention through organic farming practices is a viable strategy to enhance crop production in water-scarce regions, contributing to food security, water conservation, and the overall resilience of agricultural systems. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2025
- Full Text:
- Date Issued: 2025-04
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