Impact of climate change adaptation on paddy yield in dry zone Sri Lanka: A case study using agricultural production systems simulator (APSIM) model

Abstract

Climate change in terms of increased temperature and variation of rainfall patterns is evident in Sri Lanka. Being a country with an agro-based economy, the impact of the changes of the climate negatively affects crop production and a possesses threat to food security. Using a crop modelling approach, the impact of climate change adaptation on paddy, which is the major crop in the country was assessed in Thanamalwila (6.43ºN, 81.09ºE), Sri Lanka. The calibrated and validated Agricultural Production Systems Simulator (APSIM) model was used for yield simulations. Bias-corrected future (2040-2069) climate data were obtained from 3 general circulation models; BNU-ESM, CSIRO-Mk3-6-0, and GFDL-ESM2M under the RCP4.5 scenario. Short season (BG300) and long season (BG358) cultivar, late and early planting (both by two weeks) were used as adaptation methods. Average paddy yield under baseline (1980-2009) climate for BG300 and BG358 were 3711 and 4524 Kg ha-1, respectively. In BG300, the average future yield decreased in all 3 GCMs while in BG358 (long season), the average yield increased under 2 GCMs except CSIRO-Mk3-6-0. On average, delayed planting by 14 days as an adaptation measure increased the yield of BG300 (2.43%), the short season cultivar while in BG358, the average yield decreased by 3.55%. Except for CSIRO-Mk3-6-0 (in BG358), paddy yield in both cultivars decreased on early planting. This simple crop modelling exercise has shown the possibility of selection of cultivar and planting dates as climate change adaptation strategies. Further, field experiments and detailed crop model simulations are essential to validate the findings.