Much, Tongpan and Sirisupluxana (2013) analyzed the supply response for
natural rubber in Cambodia by using partial adjustment and adaptive expectation
mechanism. The rubber planted area and rubber yield are set as supply response in
their study. They used rubber prices from the last two years (year t-2), alternative crop
prices (maize), and planted area in the previous year as independent variables in
acreage response model. They used rubber prices in the previous year, alternative crop
prices (cassava), actual rainfall, and rubber yield in the previous year as independent
variables in the yield response model. The finding showed that the expansion of
rubber area planted, improvement in the rubber yield and rubber supply are affected
by rubber price, rainfall and alternative crop prices. Other factors such as the planted
area in the previous year and rubber yield in the previous year also relate to rubber
supply. The rubber cultivator responsiveness to the natural rubber price was inelastic
in the short- run but elastic in the long- run. They recommended that in order to
increase rubber production, the rubber growers should be motivated by improved
technology that increases rubber yield.