Improved decision-making on irrigation farming in arid zones using a system dynamics model

De Wit, Martin ; Crookes, Douglas J. (2013-11-27)

CITATION: De Wit, M. & Crookes, D. J. 2013. Improved decision-making on irrigation farming in arid zones using a system dynamics model. South African Journal of Science, 109(11/12), Art. #2013-0191, doi:10.1590/sajs.2013/20130191.

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The Sandveld region in the Western Cape is a low rainfall area dominated by agricultural production using groundwater resources. The rise in agricultural production in the Sandveld has led to questions regarding the region’s ecological sustainability. We developed a system dynamics model for the Sandveld system which captures land-use change, agricultural production, and groundwater abstraction and recharge. Using this model, we find little evidence that pressures on livelihoods result, either currently or in the immediate future, from ecological feedback effects. The model does indicate that the highest risks are associated with the financial viability of agriculture, in its present form, in the region. With lower margins, a drive towards economies of scale in agricultural production is more likely in the future. This process has had severe implications in some sectors already, with a 39% decrease in the number of potato producers in the Sandveld region between 2003 and 2009. These results highlight that an integrated approach to agricultural, economic and environmental management and planning is needed to capture the economic and ecological complexity and dynamics of the Sandveld system.

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