Marjan Sommeijer traveled to the Baviaanskloof in South Africa in 2010 to conduct research for her Bachelor's internship in International Land and Water Management at Wageningen University.
The Baviaanskloof is an extremely arid and heavily degraded area as the result of farming. This means that it is hard for the soil to retain the little rainwater that falls, causing serious erosion. To counter this, it was decided to (re)plant spekboom trees. This tree originates from the region, and does not need much water. The idea is that spekboom trees will retain the soil and, most importantly, the groundwater better and for longer. However, that costs a lot of money. Therefore, initial research was required to measure the true effect of (re)planting the spekboom trees.
To measure the effect, Marjan used the Royal Eijkelkamp rainfall simulator. 'It is a tank of half a square meter that can hold two litres of water. I alternated between placing it on a piece of soil with trees, and one with no trees. The water hit the soil in droplets via the rainfall simulator. I collected the water that was not absorbed into the soil, which allowed me to calculate the amount of water uptake by the soil.'
Marjan is very enthusiastic about the Royal Eijkelkamp rainfall simulator. The instrument is relatively easy in use and it shows clear and reliable effects.
The rainfall simulator is a really great tool that makes it relatively easy to show the effects of vegetation on interception and infiltration.
The research showed that (re)planting spekboom trees does indeed have a substantial effect on water retention. Water retention was up to 80 per cent better than on unplanted soil. The research also helped to make the land-users aware of the problem, precisely because it is a simple and transparent research method.
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