Effect of organic cultivation of rooibos tea plants (<i>Aspalathus linearis</i>) on soil nutrient status in Nieuwoudtville, South Africa

<p>The shoots of rooibos (<i>Aspalathus linearis</i> (Burm.f.) R.Dahlgren) plants, cultivated organically by small-scale farmers in Nieuwoudtville, are harvested for the production of tea. These practices could lead to decreasing soil fertility. It was hypothesised that soil from cultivated rooibos plots will have lower nutrient concentrations than soil from adjacent uncultivated plots. Soil and shoot samples were collected in December 2005, 2006 and 2009 from cultivated fields of increasing plot age and from adjacent uncultivated plots on three farms, and analysed for nutrient concentration. Compared with the uncultivated plots, no measured soil nutrients including concentrations of phosphorus (P), exchangeable potassium (K), magnesium (Mg) and calcium (Ca), and soil carbon (C) decreased in cultivated plots over the five-year period of assessment. Soil C correlated positively with concentrations of soil exchangeable K, Mg and Ca, and sodium (<i>P</i><0.001), indicating that soil C is an important indicator of soil fertility. Foliar P increased, and consequently the nitrogen:P ratio decreased in cultivated relative to uncultivated plants, implying higher P-uptake by cultivated plants. Overall, organic rooibos cultivation in Nieuwoudtville appears to be sustainable in terms of maintaining soil nutrition because soil nutrient status did not decrease over the five-year period.</p

Linking indigenous and scientific knowledge of climate change

We explore the connections among indigenous climate-related narratives, documented temperature changes, and climate change impact studies from the scientific literature. We then propose a framework for enhancing synthesis of these indigenous narratives of observed climate change with global assessments. Our aim is to contribute to the thoughtful and respectful integration of indigenous knowledge with scientific data and analysis, so that this rich body of knowledge can inform science and so that indigenous peoples can use the tools and methods of science for the benefit of their communities if they choose to do so. Improving ways of understanding such connections is critical as the Intergovernmental Panel on Climate Change Fifth Assessment Report process proceeds