Impacts of weather pattern changes and a drought index on tea productivity in three main tea growing elevations of Sri Lanka


JKMCD Perera* and E Lokupitiya

Tea is one of the major export crops in Sri Lanka and grown in high, mid and low elevations. Recently, the highest yields have been obtained from low elevations. This study was conducted to study the impact of changing weather patterns and the effect of a drought index (DI) incorporating evapotranspiration (PET) and precipitation on tea productivity. The period of study was 2006-2017. Six sites were selected, two representing each elevation level. The productivity data and rainfall measurements were obtained from the sites, and temperature and humidity data were collected from the Department of Meteorology and the Tea Research Institute. Regression analyses were conducted between the tea productivity and weather parameters. According to the findings previous month’s total rainfall, mean temperature of the current month and the relative humidity positively impact the tea yield in low elevations. Monthly relative humidity negatively impacts the tea yields of mid elevations while the rainfall of the previous month and the mean temperature of the current month impact positively on the yield at mid elevations. There was no significant impact of relative humidity on the tea yield of high elevations, but the yield was positively impacted by rainfall and temperature. According to the statistical model relationships DI two months prior to the current month negatively effect on the tea yield of low elevations and DI four months prior to the current month negatively affected the tea yield of mid elevations. In high elevations DI of the previous month and two months prior to the current month had a negative impact on tea yield. The latter findings imply that DI within the previous 2-4 months could have a significant impact on the tea productivity in a given month, depending on the elevation


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