IDENTIFYING INDIRECT FACTORS INFLUENCING PRODUCTIVITY IN PROTECTED HORTICULTURE: THE CASE OF GREENHOUSES IN THE SPANISH MEDITERRANEAN COASTLINE

The paper deals with the identification of indirect factors inducing productivity in south eastern Spanish horticultural greenhouses. From a survey of 145 protected vegetables growers in the coastline of the Granada province (Spain), a Standardized Productivity Index (SPI) has been performed, allowing to compare yields from different crops by referring each yield value to its own average and correcting the resulting values by its standard deviation. A regression model has been specified and estimated in order to analyse the relationship between the SPI and different variables that could be expected to have any indirect influence on yield. From this analysis, several factors indirectly related with productivity have been identified, namely: the farmer’s level of horticultural training, the adoption of a quality system (mainly EUREPGAP), the use of family manpower for the greenhouse works, and, in a lesser extend, the type of crop and area. No relationship with productivity has been found for variables like: farmer age, the fact of belonging to a cooperative, the type of green¬house structure and the grower assumption of risk. No significant scale effect on productivity has been found, either. From these results, some conclusions have, finally, been drawn.