Canola serves as a very favorable crop to produce oil world wide. Canola production in
South Africa is mainly restricted to the Western Cape Province under winter rainfall
conditions. The Protein Research Foundation propagated the production expansion to the
central part of South Africa. The semi arid area (Central part of South Africa) is
characterized by variable and unreliable summer rainfall. Irrigation is therefore vital for
sustainable production of a winter crop like canola. The aim of this study was to establish
the cropâs plasticity ability, water use, water use efficiency and transpiration coefficient
under a range of water application and plant density treatments combinations for the
central South Africa.
An experiment with a line source sprinkler irrigation system was conducted near
Bloemfontein in the Free State Province. Water applications, excluding 57 mm rain were:
W1 = 118 mm, W2 = 176 mm, W3 = 238 mm, W4 = 274 mm and W5 = 363 mm. These
water applications were combined with the following planting densities: PD25 = 25plants
m-2, PD50 = 50 plants m-2, PD75 = 75 plants m-2, PD100 = 100 plants m-2, PD125 = 125
plants m-2.
Seeds (1564 - 4653 kg ha-1) and biomass (3150 - 6733 kg ha-1) yields induced by the
treatments proved that canola has a high plasticity. This is because over the full range of
water application treatments optimized yields were realized at only one plant density
though different for seed (25 plant m-2) and biomass (75 plants m-2) yields. Compensation
of yields at lower plant densities resulted from branches and hence pods per plant.
Total evapotranspiration increased linear (r2 = 0.97) from 245 mm with 118 mm water
application (W1) to 421 mm with 363 mm water application (W5) but was not influenced
by plant density at all. Water use efficiency confirmed the optimum plant density for
fodder production is 75 plants m-2 and for seed production is 25 plants m-2. The water use
efficiency at these two plant densities were 12.9 kg ha-1 mm-1 and 9.6 kg ha-1 mm-1,
respectively. The β coefficient of canola was constant (2.26) for the full to moderate irrigation regimes
(W5 - W3), but not for the low irrigation regimes (W2 - W1). The β coefficient of 2.26
was used to separate the evapotranspiration of the W3 - W5 treatments into evaporation
(56%) and transpiration (44%). This method was not suitable to establish the influence of
plant density on the two components of evapotranspiration. A transpiration coefficient of
0.0045 was calculated for canola when planted for fodder at an optimum plant density of
75 plants m-2 under moderate (W3) to full (W5) irrigation.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-10122009-104801 |
| Date | 12 October 2009 |
| Creators | Angelique, Seetseng Keletso |
| Contributors | Prof CC du Preez, Prof LD van Rensburg |
| 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-10122009-104801/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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