Ali Chebil

Decomposition of output growth in the Tunisian olive-growing sector: A frontier production function approach

Abstract The aim of this paper is to investigate the relative contribution of technical efficiency, technological change, and increased input use to the output growth of the Tunisian olive oil growing farms, using a stochastic frontier production function approach applied to panel data for the period 1995–1997. The proposed methodology is based on the use of a flexible translog functional form. Results indicate that technical efficiency of production in the sample of olive producing farms investigated ranges from a minimum of 24.8% to a maximum of 84.6% with an average technical efficiency estimate of 48.5%. This suggests that olive producers may increase their production by as much as 51.5% through more efficient use of production inputs. Further, the production is characterized by decreasing returns to scale, which on average was 0.8. Finally, investigation of the sources of production growth reveals that the contribution of conventional inputs (labor, in particular) and technical change are found to be the main source of that growth, since total factor productivity increased during the study period, but at a slowing rate.

Economic Impact of Climate Change on Tunisian Agriculture: The Case of Wheat

This paper measures the potential economic impact of climate change on durum wheat in Tunisia using the Ricardian approach. A model using panel data was estimated for the period 1990–2010 over the main cultivation regions. Gross margin of the durum wheat under rainfed conditions was used as the dependent variable while the explanatory variables were mainly related to climate such as precipitation and temperature, technological progress, and type of soil. Empirical findings show that precipitations during different stages of the growing season affect positively net-income. In addition, the interactions variables between temperature and precipitation in different growth stages are negative. The assessment impact of technology shows a positive coefficient of trend parameter but not statistically significant. Finally, the soil quality index parameter is positively correlated with the net revenue per hectare. This finding indicates that good quality of soil may improve the net income of farmers by increasing wheat yields. Climate change impact was simulated using scenarios from the HadCM3 global circulation. Empirical results indicate that economic impacts are not uniformly distributed across the different regions of Tunisia. These impacts are likely to be more accentuated in the arid regions. A rise in temperature and a reduction in rainfall would cause reductions in gross margin by 4 % in sub-humid areas and 24 % in arid zones. The results further suggest the necessity for wider diffusion of drought-tolerant varieties among farmers and the identification of new agricultural practices as advisable adaptation strategies in order to alleviate the effects of climate change on farmer’s income.