Agricultural land use mapping in the sudanian savanna of West Africa: Current status and future possibilities

Multi-temporal Landsat data covering the Bawku West district of Ghana were aligned to the agro-ecological calendar to map agricultural land use. Phenological curves based on NDVI and NIR were extracted. A decision tree classification based on the curves enabled the mapping of six broad classes. Results indicate the successful discrimination of irrigated land from other land use classes, but also the problem of separating natural vegetation from quasi-natural rainfed agriculture. This problem is attributed to the scale on which agriculture is practiced (small scale) and the inadequate spatial and temporal resolution of the Landsat instrument to capture the agricultural fields and cropping systems. In the following months multi-temporal (monthly) 6.5-meter RapidEye, complemented with 6-meter TerraSAR-X observations in the rainy season will be acquired for 2012 and 2013. The synergetic analysis of data from these satellite systems with contemporary field data on cropping cycles promises to improve agricultural land use mapping in this savanna region.