Project Number
US EE SJ
Project title
Exploiting landscape heterogeneity: An investigation into vigour and physiology of grapevines on and off ‘heuweltjies’
Project leader
Jacobs, S M
Institution
University of Stellenbosch. Department of Conservation, Ecology and Entomology
Team members
Jacobs, S M
Shange, P
Ellis, F
Hoffman, E
Strever, A E
Project description
‘Heuweltjies’ are landscape features within many vineyards in the Western Cape, and are associated with the activities of a species of harvester termite. Studies conducted in natural veld show that physical and hydrological properties of soils associated with heuweltjies are significantly different from surrounding soil, resulting in altered growth characteristics of individual plants and altered plant community structure and productivity. Recent work in vineyards in mesic areas shows that increases in productivity may be present in Vitis vinifera associated with heuweltjies, with possible consequences for wine quality. Conversely, evidence suggests that the opposite is true for drier climates, with lower productivity of the vines affected by heuweltjies than elsewhere in the vineyard. We hypothesize, based on work carried out within natural and cultivated landscapes that, in addition to altered soil physical and hydrological properties, productivity, physiology and phenology of vines and wine quality on heuweltjies may be significantly different from those off heuweltjies. We intend to carry out a pilot study to investigate differences in vigour, physiology, phenology, wine quality as well as basic soil properties between grapevines growing on the heuweltjies and those growing off heuweltjies. Our overarching objective is to determine what the effects are of the persistence of heuweltjies in cultivated landscapes in mesic and dry climates (Stellenbosch and Robertson areas, respectively) for grapevine vigour, and what, if any advantages and disadvantages this lend to agricultural activities. The project will form the bulk of an MSc study supervised jointly by the Departments of Soil Science, Viticulture and Enology and Conservation Ecology and Entomology at the University of Stellenbosch. Once the effects of heuweltjies on grapevines have been established, we intend pursuing an investigation into the causes of altered growth characteristics and the mechanisms underlying altered physiology of grapevines on heuweltjies.
Poster(s)
Jacobs, S M, Booi, N, Bekker, S, Ellis, F, Esler, K, Hoffman, E, Milton, S and Strever, A E. 2011. Landscape legacies: Biogeochemical and ecohydrological properties of natural and cultivated ‘heuweltjies’ (mima-like mounds) of the fynbos and succelent Karoo in South Africa. Poster presented at the 12th MEDECOS Conference. 6-9 September, Los Angeles, United States.
Presentation(s)
Booi, N, Bekker, S, Jacobs, S M, Esler, K J, Hoffman, E, Strever, A E and Ellis, F. 2011. ‘Heuweltjies’ are hotspots for biochemical processes and have unique eco-hydrological properties, and this effects crop quality even after cultivation. Paper presented at the 37th Conference of the South African Association of Botanists. 17-19 January, Rhodes University, Grahamstown, South Africa.
Thesis
2011. Exploiting soil and terrain heterogeneity: An investigation into vigour and physiology of grapevines on and off heuweltjies in the Western Cape, South Africa. MSc. University of Stellenbosch, Stellenbosch, South Africa.