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.
