Rubber Research Institute of Sri Lanka – Polgahawela Substation

The Polgahawela Sub-station of RRISL (Low Country Intermediate Zone) was established in 2004 at Narampola estate which is situated in Alawwa divisional secretariat division in the Kurunegala district in the North Western Province. Geographical coordinates of the location are 800 14’ E Latitude and 70 21’ N Longitude.

Daily rainfall measurements are recorded at the substation and reported to the Biometry division of RRISL. Annual rainfall pattern of the location holds the usual bimodal distribution showing the highest peak during the north east monsoon period which is clearly depicted in the following graph of the monthly rainfall distribution of the substation based on 10-year monthly rainfall averages.

The following graph shows the variation of total annual rainfall during last ten years. For this period, the highest annual rainfall was reported in 2014.

Area under cultivation

19.25 ha of land have been cultivated with rubber out of which 17.75ha is under tapping. With the aim of conservation of rubber germplasm, a conservation plot of non-wickham collection is maintained at the substation which was established during 2017 by the Genetics and Plant Breeding Department. The clone composition at the substation is given in the table below.

Production of rubber

During 2019, the total production was 15678kg which was 86% of the estimated crop. Yield per hectare for 2019 was 883kg. About 73% of the total RSS produced at the substation was sold as grade 1, emphasizing the quality of processed rubber at the substation. The average intake per tapper during last year was 9.4kg while the highest intake per tapper of 11.22kg was recorded from the 2008 clearing with a tapping task of 269 trees of clone RRIC121 tapped on D3 system.

Tapping details