Application of GIS in Land Evaluation and Development of Suitability Map for Capsicum Production in Nairobi Peri-Urban Counties

Abstract

This study was carried out to determine the areas which are best suited for capsicum (Capsicum annuum L.) production in the peri-urban counties of Nairobi, Kenya. The study used a multi-criteria evaluation approach by applying the Analytic Hierarchy Process (AHP). Soil (pH, drainage, texture, and electrical conductivity), climate (temperature and rainfall), and topography (slope and elevation) were the main criteria selected from literature for the study. The AHP was used to determine the relevance of a criterion based on its cumulative weights as per the Saaty’s table. The cumulative weights were used to construct output maps using Quantum Geographic Information Software (QGIS) software. Crop suitability map was produced through overlaying of the different thematic maps and suitability levels were based on Food and Agriculture Organization (FAO) land suitability classification. The results showed that about 50% of land in Kiambu County, 8% in Kajiado County and 12% in Machakos County is suitable for capsicum production. The remaining areas were reported unsuitable for the production of the crop due to the presence of some limitations such as soil texture, soil pH, drainage and climate. The findings of this study will be useful to decision making and planning and for further studies.