Final Technical Report - weADAPT

climate data from climate scenario, which was generated by CCAM climate model, as
input, which include maximum and minimum temperature, precipitation, solar radiation,
etc. and coupled with crop management scheme and soil property to calculate the yield of
rice productivity. By using daily climate data for the simulation process, this study is able
to capture the impact of climate change on rain-fed rice production not only in terms of
the change in degree of intensity of each climate parameter, e.g. increase or decrease in
rainfall or temperature, but also change in temporal aspect too, e.g. shifting of the onset
or changing on the length of rainy season or change in the pattern of mid-season dry spell
period, etc.
The crop management scheme used in the simulation process was based on
assumed homogeneous practice at each site to simplify the calculation process. Crop
managements comprised of crop cultivars, planting field, initial condition of the field
before planting, planting detail (method and plat density), water management, and both
organic and inorganic fertilizer application.
5.3.2 Results: Impact of climate change on rice productivity in lower Mekong River basin
Farming systems in Lao PDR and Thailand are single crop cycle per year due to
the length of the rainy season. Viet Nam farming system adopt dual crop as the rainy
season is longer in the Mekong River delta area. The climate change from the CCAM
climate model shows slight negative impact on the rain-fed rice productivity in Lao PDR.
The simulated yield of rice productivity in Savannakhet province would reduce by 10%
under climate condition at CO 2 concentration of 540 ppm but will increase back to almost
baseline condition under the climate condition at CO 2 concentration of 720 ppm.
The simulation of rice productivity at the study site in Ubonratchathani province,
Thailand, shows that climate change has positive impact on the rice production in the
area. The simulation result shows trend of increasing yield of rice productivity under
future climate condition. The increase in productivity yield could be as high as 10-15% in
some areas.
In Viet Nam, the simulation result shows different climate impacts on yield of rice
productivity in different crop cycle. The winter-spring crop may get slight positive
impact, of which the productivity would slightly increase by approximately 3-5% under
Final technical report – AIACC AS07 51