An indigenous soil classification system for Bellona Island - a raised atoll in Solomon Islands

One of the challenges of evaluating existing traditional farming systems is to combine local knowledge and modern scientific methods and terminology. This requires an evaluation of indigenous soil classification in modern terms. This paper focuses on an indigenous soil classification system developed by local farmers on the island of Bellona, Solomon Islands. The definitions of the different soil types are described and the principles of the classification system and the applicability of ethnopedology in soil surveys are discussed. Based on interviews with about 20 per cent of the farmers on the island as well as standard soil chemical and physical determinations on main soil types, an evaluation of the soil types for cultivation of various crops is carried out. The soils on Bellona are developed on oolitic or clayey phosphate-rich deposits forming the basis for the agriculture production on the island. The Bellonese soil classification system is mainly based on the physical properties of the humus-containing top layer. Subsoil layers are only used for classification if they are very close to the surface and may be mixed with the topsoil. Results show a general agreement among farmers, who perceive the same four out of seven soil types as highly useful for cultivation and rank these soil types similarly according to their suitability for different crops such as yam, watermelon, cassava and sweet potato. It is concluded that the indigenous soil classification is in line with the soil production potential and useful for land evaluation on Bellona.