The ecophysiological characterisation of terroirs in Stellenbosch : the contribution of soil surface colour

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dc.contributor.advisor Carey, V. A.
dc.contributor.advisor Hoffman, J. E.
dc.contributor.advisor Strever, A. E. Witbooi, Erna Hailey en_ZA
dc.contributor.other Stellenbosch University. Faculty of AgriSciences. Dept. of Viticulture and Oenology. 2008-06-24T12:45:10Z en_ZA 2010-06-01T08:40:21Z 2008-06-24T12:45:10Z en_ZA 2010-06-01T08:40:21Z 2008-03 en_ZA
dc.description Thesis (MScAgric (Viticulture and Oenology))--Stellenbosch University, 2008.
dc.description.abstract Soil is a component of the environment and sustains growth of several plants and animals. It forms part of the biosphere and can be described as the interface between the atmosphere and the lithosphere. The interaction between soil, climate and topography and the resulting agricultural aptitude forms the concept of terroir. This relationship is complex and it is difficult to quantify the contribution of each. Grapevines are exposed to an array of soil types. Soils have varying colours, which can be ascribed to their origin from different parent materials and pedogenetic factors. Historical and experimental evidence points to the key role that soil physical conditions play in determining grape berry composition, but other soil related factors may also play a role. This study was conducted to investigate the effect of soil surface colour on the vegetative and reproductive growth characteristics of Cabernet Sauvignon. The aim was to determine whether a relationship exists between soil colour, reflective light quality below and inside the grapevine canopy, vegetative growth of the grapevine and the berry and wine composition. The reflected light from soils was measured in three positions of the canopy and across the light spectrum (300–2500 nm) for three different soil surface treatments (black, red and grey). The effect of soil colour on vegetative parameters, yield and berry composition and wine quality was investigated. Soil surface colour resulted in differences in the reflected light quality below and in the canopy. The differences in the light quality were associated with differences in vegetative parameters such as mean main leaf, with grey soils inducing higher values. Potassium levels of the grapes and berry number per bunch appeared to be influenced by soil surface colour throughout berry development with red and black soils having higher levels of potassium and berry number per bunch than grey soils. Grape ripening parameters were not influenced by soil surface colour, but the grey treatment had a significantly more intense grape colour measured at 520 nm (red pigments). It is assumed that the importance of soil colour is its association with the physical and the pedogenetic properties that contribute to the grapevine water balance. From these results it can be concluded that soil surface colour appeared to have a direct effect on some aspects of vegetative and reproductive growth, and berry composition, but the contribution of different wavebands and mechanism of their effect deserves further study. en_ZA
dc.language.iso en en_ZA
dc.publisher Stellenbosch : Stellenbosch University
dc.subject Soil surface colour en_ZA
dc.subject Light quality en_ZA
dc.subject Light quantity en_ZA
dc.subject Reflectance en_ZA
dc.subject Terroir -- South Africa -- Stellenbosch en
dc.subject Viticulture -- South Africa -- Stellenbosch en
dc.subject Soils -- Color -- South Africa -- Stellenbosch en
dc.subject Plant-soil relationships en
dc.subject Dissertations -- Africulture en
dc.subject Theses -- Agriculture en
dc.subject Dissertations -- Viticulture and oenology en
dc.subject Theses -- Viticulture and oenology en
dc.title The ecophysiological characterisation of terroirs in Stellenbosch : the contribution of soil surface colour en_ZA
dc.type Thesis en_ZA
dc.rights.holder Stellenbosch University
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