Evaluation of Productivity of Potatoes in Nuwara Eliya and Badulla Districts with the Aid of GIS Techniques

Abstract

GIS based model was used as spatial biophysical model to evaluate productivity of potatoes in Nuwara Eliya and Badulla Districts. A field survey was conducted in central hills of Sri Lanka under field conditions in yala and maha seasons during 2003-2005. Results revealed that fresh tuber yield performance of potatoes varied markedly as a function of seasonal climatic variations, soil chemical properties and applied cropping systems. The yala season being relatively drier than maha season produced a remarkably higher potato tuber yield than that of maha season during 2003-2005. It was also observed that paddy field grown potato plants were free from bacterial wilt disease whereas late blight was the major destructive disease. Reduction in tuber yield was positively correlated with wilt and late blight diseases. According to the composite scores in GIS model the highest score was recorded in Welimada in maha season. However, Medawela recorded the lowest value due to deviation from optimum soil pH. In yala season the highest composite score was recorded in Boralanda which is compatible with benefit to cost ratio of Boralanda. In bothyala and maha seasons composite scores and average fresh tuber yield were positively correlated in all clusters. According to the results the average highest yield during three year period (2003 -2005) was recorded in Boralanda and Welimada clusters in yala and maha seasons respectively. Results of the present study revealed that Granola produced higher yields constantly for the six seasons throughout the study period under climatic conditions of central hills of Sri Lanka.