Irrigation Water Use Efficiency and Fann Size in Tunisian Agriculture: A Parametric Frontier Analysis Approach

In an economy such as Tmrisia where resources are scarce and opportunities to use new
technologies are limited, efficiency is a very important factor for productivity growth. Inefficiency studies
indicate the potential to raise productivity by improving efficiency without necessarily developing new
technologies or increasing the resource base. The objective of this study was to measure productive efficiency
of irrigation water use based on the concept of technical efficiency and through comparing different sized farms
in TWlisia. The proposed methodology was applied to a randomly selected sample of 144 citrus growing
farms in the north of the country during 2003-2005 and differentiated by size (small, medium and large farms).
A stochastic frontier production fWlction, in which the non-negative technical inefficiency effects are assumed
to be a fWlction of farm-specific variables, is defined for cross section data on farms. The fWlction is used to
obtain farm -specific estimates of technical and irrigation water efficiency and to ascertain the effect of factors
influencing irrigation water efficiency differentials across citrus growing farms. This study has revealed that
small scale citrus farmers are not fully technically and irrigation water efficient and therefore there is potential
for efficiency improvement, in both technical and irrigation aspects by addressing some important policy
variables that negatively and positively influenced farmers' levels of efficiency. Another consistent result of
this study is that medium size farms are the most efficient from a technical, irrigation and irrigation technical cost
efficiencies point of view. Indeed, this study's most important contribution to the continuing debate over the
relationship between efficiency and farm size is an affirmation of the inverse relationship in the case of citrus
growing farms in TWlisia. Through this "lens", it is not surprise that medium size farms are the more efficient
users of productions factors, especially water. A further rationale for these initial results, regarding increased
technical water use efficiency with high quality agricultural practices, was the price premium for these
farmers. This highlights the need for government policies, through extension activities, to set up professional
training programs in advanced irrigation techniques. This could be effective, particularly if targeted at farmers
with limited skills and would also stimulate innovation if decisions makers encouraged investment in irrigation
equipment machinery by facilitating access to credit.