Land evaluation is currently important in South Africa. Soilscape surveys can make a
contribution in this connection by bridging the gap between land type surveys and detail
surveys. Land Type Dc17 (area = 237 651 ha) east of Bloemfontein include the densely
populated areas near Botshabelo and Thaba Nchu. The objective of this study was to
subdivide Land Type Dc17 into smaller more homogeneous land units, to estimate the
area of each unit suitable for maize and sunflower production using the In-field
Rainwater Harvesting technique (IRWH), and to estimate attainable yields of these crops
on the available areas. The soilscape survey technique was developed to serve this goal.
Soilscape is defined for this specific study as a mapping unit consisting of a portion of
land mappable at a scale of 1:50 000 in such a way that it facilitates the identification of
potentially arable land. Earlier Northcote (1978) described soil landscapes as areas of
land that have recognizable and specifiable topographies and soils, that are capable of
presentation on maps, and can be described by concise statements
The delineation of 66 soilscapes was done on 1:50 000 maps. Detailed pedological
investigations were made on selected pedoseque nces of some soilscapes using 1:10 000
maps, soil pits, auger holes and depth probe observations. Nine soilscapes with a total
area of 82 222 ha were found non-arable. For the remaining 57 soilscapes, covering an
area of 155 429 ha, the improved knowledge gained during the detail studies was
extrapolated to estimate the area of each one suitable for IRWH. The result was
56 875 ha, or 24 % of the total area of Dc17. The results of previous field experiments
on relevant ecotopes predict the following maize yields in tons/ha/yr: conventional
tillage = 82 000; simplest type of IRWH = 127 000. It is therefore estimated that this
land type can provide the staple maize diet for about 600 000 people using IRWH. The soilscape survey technique proved successful within this land type, but should be
refined for application to other land types and other feasibility studies.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-11102005-082435 |
| Date | 10 November 2005 |
| Creators | Tekle, Semere Alazar |
| Contributors | Dr PAL le Roux |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-11102005-082435/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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