AGRO CLIMATIC RISK ASSESSMENT IN HAMBANTOTA REGION
DOI:
https://doi.org/10.31357/fesympo.v0i0.1535Abstract
In order to eliminate the risk on crop production in Hambantota region, spatial andtemporal variation of rainfall were analyzed based on rainfall magnitude, duration, riskand onset. The rainfall data over 42 years (1960-2002) in six rain gauge stations inHarnbantota region was assessed
10 mm weekly rainfall at 75% probability level method was used to find the wet weeks ineach station throughout the year. 10 mm weekly rainfall at 50% probability level wasused for rainfall onset identification. Farmer survey was conducted to find the existingcropping calendar. The amount of rainfall, which accumulated on the date of cropcommencement, was identified using Forward accumulation method
The results revealed that mean annual rainfall is decreasing in Harnbantota region. Allstations were recorded less than 20% wet weeks. It reveals that the high risk involveswith rain fed crop cultivation in Harnbantota region. Based on the 10 mm weekly rainfallat 50% probability level, rainfall onset for yolo and moho seasons varies from 11th to 16thweek and from 37th to 42nd week respectively.The farmers could be able to minimize theirrigation need using these rainfall onset weeks as their crop commencement weeks.Based on the farmer survey, crop commencement week in moho season varies between39th and 41"t week and farmers rarely cultivate during yolo season. According to theforward accumulation method at 75% probability level the amount of water accumulatedat crop commencement time was 75mm. The results indicate that the cropcommencement week based on farmer survey coincided with calculated rainfall onsetduring moho season.
