Abstract:
The Agricultural Model Intercomparison and Improvement Project (AgMIP)
is a major international effort linking the climate, crop, and economic
modeling communities with cutting-edge information technology to produce
improved crop and economic models and the next generation of climate
impact projections for the agricultural sector. The coordinated climate-crop
modelling project (C3MP) is one of the global assessments in AgMIP.
C3MP mobilizes international crop modellers for a coordinated
investigation of climate vulnerability and climate change impacts on
agriculture aim to improve understanding of the impact of climate change on
future agricultural production by utilizing site-calibrated crop models to
coordinate projections of crop response under probabilistic climate change
scenarios.
In line with AgMIP’s attempts to develop adaptation to climate change for
agricultural sector globally and regionally, the AgMIP-Sri Lanka project
investigated the climate change impacts on rice based farming systems and
adaptation strategies, led by the Stakeholder Institutes of Department of
Agriculture and Agricultural Universities.
Commonly cultivated rice varieties (Bg300, Bg358, Bg357) in major rice
growing region (Kurunegala) where information on rice production of farm
families are available was selected for the present study. DSSAT model was
calibrated using experimental data obtained from the Rice Research and
Development Institute (RRDI). Rice yield was simulated for 104 farmer
fields for two growing seasons (major and minor) for the base years (2012-
2013), baseline period (1980-2010), and mid-century (2040-2069) for five
GCMs (CCSM4, GFDL-ESM2M, HadGEM2-ES, MIROC5, MPI-ESM-MR) of RCP-8.5 scenario. According to the C3MP protocol, 99 sensitivity
tests were performed for Bg 300 and Bg 357 for RRDI experimental site in
both major (maha) and minor (yala) seasons. Climate sensitivity tests were
performed by adjusting historical climate to reflect changes to temperature,
precipitation and [CO2].
The base year (2012/2013) RMSE for both seasons range around 1200-1300
kg/ha for observed (major-season 4289kg/ha; minor-season 3883kg/ha) vs
simulated using DSSAT (major-season 4888kg/ha; minor-season
4410kg/ha). Compared to baseline period (1980-2010), a significant yield
reduction of 14%, 12%, 22%, 12%, 17% for the major-season and 31%,
30%, 42%, 28%, 35% minor-season, for the above five GCMs, was
observed respectively. C3MP Coordinators provided a bias-adjusted
MERRA Reanalysis weather time series corresponding to the site. DSSAT
model predictions were submitted via a provided template to the C3MP
Coordination team. The archived results were vetted and fit with an
emulator to estimate yield response surfaces. These response surfaces may
then be used to analyze the impacts of projected climate changes.
