Measuring Irrigation Water Efficiency with a Stochastic Production Frontier: An Application for Citrus Producing Farms in Tunisia

The objective of this paper is to propose an alternative measure of irrigation water efficiency based on the concept of input- specific technical efficiency, which contracts with measures previously used in the literature. The proposed methodology is applied to a randomly selected sample of 144 citrus growing farms located in Nabeul (Tunisia). A stochastic production frontier approach, based on Battese and Coelli’s (1995) inefficiency effect model, is used to obtain farm-specific estimates of technical and irrigation water efficiency. In addition, a second-stage regression approach is used to identify the factors influencing irrigation water efficiency differentials across citrus growing farms. Results indicate that technical efficiency ranges from a minimum of 12.9% to a maximum of 90.7% with an average estimate of 67.7%. This suggests that citrus producers may increase their production by as much as 32.3% through more efficient use of production inputs. Further, mean irrigation water efficiency is found to be 53%, which is much lower than technical efficiency and also exhibits greater variability ranging from 1.6% to 98.87%. The estimated mean irrigation water efficiency implies that the observed quantity of marketable citrus could have been maintained by using the observed values of other inputs while using 47.0% less of irrigation water. Moreover, the estimated mean irrigation water technical cost efficiency is found to be 70.81% indicating a potential decrease of 29.19% in total cost by adjusting irrigation water to its efficient level. In addition, the vast majority of farms have achieved irrigation water technical cost efficiency greater than 90% (71% of farms). Finally, the analysis of the sources of efficiency differentials among farmers showed that farmer’s age, farm’s size, education level, agricultural training, the share of productive trees and the water disposable perception tend to affect positively the degree of both technical and irrigation water efficiency.Citrus, Efficiency, Tunisia, Water, Agricultural and Food Policy, Community/Rural/Urban Development, Demand and Price Analysis, Environmental Economics and Policy, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, International Relations/Trade, Marketing, Productivity Analysis, Research and Development/Tech Change/Emerging Technologies,

Measurement and Sources of Technical Inefficiency in the Tunisian Citrus Growing Sector

This paper investigates farm level technical inefficiency of production and its determinants in a sample of 150 citrus producing farms in Tunisia using a stochastic frontier production function approach applied to cross section data. Results indicate that technical efficiency of production in the sample of citrus producing farms investigated ranges from a minimum of 26.84% to a maximum of 97.98% with an average technical efficiency estimate of 86.23%. This suggests that citrus producers may increase their production by as much as 13.77% through more efficient use of production inputs. Further, the estimated coefficients in the technical inefficiency model indicate the positive effect on technical efficiency of the share of productive trees, the agricultural training, irrigation operations and the experience of farmer.Technical Efficiency, stochastic frontier production function, citrus farms, Tunisia, Productivity Analysis,

Nutrient effects in consumer demand systems: evidence from panel data

Preprin

Livestock for resilience : Revisiting the role of livestock in the major agricultural production systems of the MENA region

This paper aims to analyze the contribution of livestock to the resilience of major agricultural systems in the MENA region. We considered study areas from Jordan, Tunisia, and Morocco. We started by providing a typology of resilience profiles of production systems in these study areas and then we calculated resilience indexes for the identified farm types in the different countries. Secondly, we analyzed the role of livestock in each of these systems by testing the correlation between a set of livestock variables and the resilience indexes. Results show that livestock is playing a crucial role in enhancing agricultural systems resilience in the MENA region. Mixed crops-livestock systems, in addition to the pastoral production systems, identified in the considered countries, were found to have significantly high resilience indexes. Beside being an important source of income in the dry rain fed areas, animal heads are being considered as assets that could be easily converted into cash to face financial shortage and crisis. Our results also show that livestock producers appear to be more socially engaged and more open to their neighborhood, this is mainly due to practicing transhumance and sharing rangeland with other farmers, which enhances their positioning over the resilience scale. Acknowledgement : This paper has partly benefited from the financial support of the Consortium Research Program (CRP) on Livestock, Led by ILRI. Data of the paper has been collected during the CRP Dryland System. The paper also benefited from financial support of the Erasmus Mundus program

Datos de panel y demanda de alimentos en Espana

Hasta la fecha, la mayor parte de los trabajos que han estudiado la demanda de alimentos en Espana han considerado unicamente datos de series temproales o de seccion cruzado. El principal objectivo de este estudio consiste en considerar conjuntamente las dos dimensiones para abordar este problema, tralando de ofrecer al lector unas pantas no solo para estimar sistemas de demanda con un panel de datos sino tambien para contrastar su correcta especificacion. Una segunda caracteristica de este trabajo consiste en definir un esquema general a partir del cual se pueda especificar una forma funcional del sistema de demanda que mejor se ajuste a la informacion disponible, en vez de seleccionar a priori una forma funcional determinda. Los resultados empiricos obtenidos estan en la linea de trabajos anteriores, si bien las elasticidades gasto y precio directas calculadas son ligeramente superiores, sobre todo en el caso de los productos precederos. Al analizar los efectos de las caracteristicas sociodemograficas de los indiciduos, la edad y el porcentaje de miembros de la familia menores de 13 anos son los principales determinantes del consumo de carnes, pescados y azucar, experimentandose un descenso en las cantidades consumidads de estos productos conformen aumentan dichas variables...The demand for food in Spain has been traditionally studied only considering time series or cross section data. This paper aims to analyse food demand jointly considering both data dimensions. It also provides some guidance on how estimate demand systems using a panel data set and on how to carry out misspecification tests. The second main characteristics of this paper is that instead of selecting an a priori functional form, we provide a flexible approach from which the functional form which fits better the data can be selected. Empirical results are consistent with those found in precious literature although expenditure and price elasticities are slightly higher for perishable products. As far as the socio-demographic characteristics of households, the age and the percentage of household members below 13 years are main determinants of meat, fish, and sugar consumption. Consumed quantities of these products decrease as the two considered variables increase

La demanda de carnes y pescados en Túnez: un enfoque dinámico

El objetivo de este trabajo consiste en analizar la demanda de carnes y pescado en Túnez utilizando sistemas econométricos multiecuacionales en base a datos de series temporales para el período 1973-1997. Se ha prestado especial atención a la especificación del modelo y al cumplimiento de las restricciones teóricas. Desde el primer punto de vista, se ha optado por un enfoque dinámico general que permite seleccionar la forma funcional que mejor se ajusta a los datos. Los resultados del análisis indican que un sistema en forma de modelo de corrección del error es el más adecuado para analizar la demanda de carnes en Túnez. Desde el segundo punto de vista, el modelo estimado cumple las restricciones de homogeneidad, simetría y negatividad con lo que es perfectamente compatible con la teoría de la demanda. Excepto el pollo, que es considerado como un bien de primera necesidad, las carnes de cordero y los pescados presentan elasticidades unitarias, mientras que la carne de vacuno se comporta como un bien de lujo. Con respecto a las elasticidades precio, la demanda de todas las categorías de carnes y pescados es inelástica......The aim of this paper is to analyse the demand for meat and fish in Tunisia using multiequational econometric systems with time series data for the period 1973-1997. Special attention has been paid to two issues: model specification and theoretical restrictions testing. In relation to the first issue, a fairly general dynamic framework has been used in order to specify the dynamic version of the AIDS model which fits better the data. Results from specification tests indicate that the system in error correction form adequately describes the behaviour of Tunisian consumers. In relation to the second issue, the estimated model satisfies the homogeneity, symmetry and negativity restrictions making it compatible with demand theory. Except for chicken, that can be considered as a necessity, lamb and fish expenditure elasticities are close to unity while veal is a luxury good in relation to meat and fish expenditure. Finally, fish and meat are price inelastic

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

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 characterised 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 (labour, 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

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

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 characterised 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 (labour, 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.Olive oil sector, Tunisia, productivity, Crop Production/Industries, Demand and Price Analysis,