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Effect of soil and subhabitat differentiation on the growth of Tarchonanthus camphoratus seedlings from a semi-arid savanna of South Africa
Author
Smit GN
Jacobs IJ
Publisher
XII International Rangeland Congress
Publication Year
2025
Body

Large areas in the savanna of the Northern Cape Province of South Africa suffer from bush thickening, especially by species such as Tarchonathus camphoratus. Effective management of these areas requires an understanding of the factors such as allelopathy that can affect the establishment, survival and growth of T. camphoratus seedlings. The objectives of this study were to investigate whether soil originating from different subhabitats would differ in soil nutrient status and whether T. camphoratus exhibit allelopathic effects by affecting the survival and growth of seedlings grown in soil originating from these different subhabitats. Soil and ripe seeds were collected in the Northern Cape Province of South Africa on two sites of different soil types (deep sandy and shallow rocky) and within three subhabitats (close to the stems of mature T. camphoratus plants; in the middle of the canopy; and away from tree canopies in the uncanopied zone). The trial was conducted under controlled conditions in a greenhouse over a period of 18 months and consisted of six treatments with ten replications. Soil analyses, including Na, Mg, K, Ca, P and N were performed on the soil from the different subhabitats. Seeds germinated abundantly in all the soil samples, confirming that there are no all elopathic effects preventing their germination. Significantly higher (P<0.05) plant heights, leaf numbers and growth rates were measured in seedlings grow n in the soil originating from the canopied zone compared to those grown in soil from the uncanopied zone, while no significant differences (P>0.05) existed between the seedlings grown in soil from the same subhabitat but different soil types. The better growth of T. camphoratus seedlings in soil from the canopied subhabitats can be attributed to the higher soil nutrient status in these subhabitats. This has important implications for tree thinning operations as areas where mature trees are removed, will present ideal areas for seedling establishment, survival and growth.

Language
English
Resource Type
Text
Document Type
Conference Proceedings
Additional Information
This paper is part of the larger XII International Rangelands Congress Proceedings. Page Numbers: 1197-1201. Theme: Theme 4 / Poster presentations – Theme 4
ISSN
978-0-646-72121-7
Conference Name
International Rangeland Congress
Collection
International Rangelands Congress
Keywords
allelopathic effect
seedling growth rate
canopied zone
uncanopied zone
nutrient status