Land Evaluation and Crop Suitability Analysis – A Case Study on Karachchi Divisional Secretariat, Kilinochchi District, Sri Lanka

Abstract

Agricultural development in any region needs knowledge about the soils, their properties, and spatial distribution. Crop-land maps created using land evaluation are essential for land management. The research was conducted to develop a crop-land suitability map with “Highly Suitable”, “Moderately Suitable” and “Currently Not Suitable” categories for Karachchi Divisional Secretarial Division (DSD) (438.2 square kilometers) by analyzing soil quality. Twelve parameters and 63 sample locations were selected. Weather data such as rainfall, temperature, and relative humidity were collected from secondary sources. A slope map was created using the Digital Elevation Model (DEM) file, and the constructed questionnaire was used to obtain the drainage details. Soil depth was deduced from the wells and soil pits. The collected soil samples were analyzed to determine the parameters such as pH, electric conductivity, the sum of basic cations, base saturation, soil texture, and organic carbon. Each parameter was reclassified using ArcGISTM 10.4.1 to create parameter maps. After that, an analytical hierarchical process (AHP) was applied to each crop, and then each parameter was reclassified again with reference to FAO’s 1993 crop requirement criteria. Finally, the Weighted Overlay Analysis (WOA) was conducted to obtain the crop-land suitability map. The study revealed that 50% of the study area falls under the “Highly Suitable” category for coconut cultivation. Rain-fed paddy shows that 45% of the study area is “Moderately Suitable”. Irrigated paddy has a “Moderately Suitable” area of 48%, while nearly 51% is “Moderately Suitable” for onion. 17% of the land is “Highly Suitable” for groundnuts. The pineapple is “Highly Suitable” for 12% of the study area. A crop-land suitability map for Karachchi DSD was created. This map will be a guide for land planning decision-makers