Mapping Khat (Miraa) by Remote Sensing in Meru County, Kenya

Abstract

Khat or miraa is a plant indigenous to Eastern Africa and the Arabian Peninsula, whose leaves and stems are consumed privately and socially as a stimulant; it is highly valued by its cultivators for the high incomes it brings them. However, studies by the World Health Organization, amongst others, have found that miraa is a mild addictive drug whose continued heavy consumption can result in adverse physical and mental health effects, and therefore whose production and marketing should be discouraged. Few, if any, studies have been done to accurately quantify miraa production in areas where it grows, yet this is an important statistic for informed decision making on the crop. This paper describes a study that has mapped, using remote sensing and GIS techniques, the miraa plantations of the Igembe region of Meru County in Kenya, which is a major source of khat globally. Supervised classification of Landsat 8 imagery was carried out, with overall classification accuracy and kappa statistic of 78% and 0.72 respectively obtained. It was found that over 70,000 hectares of miraa are planted in this region, representing a regional potential per capita income of USD 2345, very high by Kenyan standards. The paper concludes that miraa is a widely grown crop of high economic significance in this region in terms of income and employment creation, and that the region’s economy would be adversely affected if the marketing of miraa were to cease.