Vitner, G., Ruppin Academic Center, School of Engineering, Emek-Hefer 40250, Israel
Bechar, A., Institute of Agricultural Engineering, Agricultural Research Organization, Bet-Dagan 50250, Israel

The study investigated the optimization of the screen house design to improve the growth productivity of green ornamentals. It focused on the labor-intensive handling operations in order to minimize the time invested in these operations and to maximize the total revenue. The research was performed during 2006-2007 in two modern farms in the central part of Israel. The farms contained 7 and 11 ha of Pitosporum and Aralia screen houses. The various stages of harvesting on each farm were subjected to work studies and time measurements, and a computer simulation model was developed with the ARENA 7™ to find an improved screen house layout. The main goal was to determine the time per stem and hourly output per worker as functions of length of row and cart location. Results show that for the examined cultivars and the present working methods, the best outcome was reached when the row length was the shortest of those examined. There was a decrease of 35% in output when row length increased from 24 to 200 m. Simulation results showed that the best length of a screen house was 24 m. Furthermore, the optimal location of the cart used to transfer the crops to the packaging house was determined.