PARENT SESSION
Poster Session #20: Arid Lands Restoration.
Tuesday, August 6. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC
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Re-vegetation technologies to restore degraded semi-arid rangelands in South Africa.
KELLNER, KLAUS*,1, VAN DEN BERG, LORRAINE1, DE WET, SARONE1, 1 Potchefstroom University for CHE, Potchefstroom, South Africa
ABSTRACT- More than 90% of South Africa's land surface is arid, semi-arid or dry-sub-humid and falls within the UNCCD definition of affected drylands. About 8% can be considered as hyper arid. Large parts of these rangelands (approx. 25%) are degraded, due to unpredictable and low rainfall events, including drought, together with injudicious land use and management practices. Represented by smaller bare patches or larger denuded areas, low vegetation cover and density, as well as high erodability, these degraded lands become unproductive for livestock production. A combination of active restoration technologies, which included cultivation with a sub-soiler (ripper) and re-vegetation by over-sowing with a mixture of five C4 warm season, perennial, high fodder grasses, were evaluated in three semi-arid, degraded areas, for increasing grazing capacity. Vegetation cover and abundance of mainly annual, low ecological status species increased in plots that were only cultivated with no over-sowing, due to the remaining soil seed bank. The sown-in species, Digitaria eriantha (finger grass), Chloris gayana(Rhodes grass) and Panicum maximum (buffalo grass), had the highest establishment rates (20-25%), increase in density and cover abundances, depending on the soil type and short term rainfall. The restoration technology which included a combination of cultivation, over-sowing and an animal dung supplement was considered the most successful. In all instances the occurrence of bare soil decreased significantly (80-5%). With the correct technology and management practice applied, degraded, semi-arid rangelands can be restored.
KEY WORDS: over-sowing, organic material, Digitaria eriantha, Chloris gayana