T.M.M. RoordaAgricultural University Wageningen, The Netherlands
In the central highlands of Ethiopia, a unique soil management system, known locally as guie (soil burning), is practiced. The physical and chemical changes resulting from soil burning were studied and analysed in the laboratory.
It was found that soil burning changed soil colours to redder hues, fused clay into sand-sized particles, decreased the organic matter content and increased the soil pH. Total N was lost in the burnt layer of the guie heap, but increased in other layers. Available P increased with higher temperatures. The cation exchange capacity, and exchangeable Ca and Mg, decreased, while K increased. In the burnt layer, the Fe content increased, whereas the Mn content decreased; Cu and Zn contents decreased with more heat.
The most favourable effects were found to be the increase in P. the increase in available N and the change to a coarser soil texture. An obvious disadvantage was the loss of organic matter.
