干旱区生态环境知识资源中心

A prototype of a closed greenhouse has been constructed in the semi-arid region of El Ejido in Almeria, Spain. It is a plastic greenhouse which minimizes the use of water and energy. This work presents the agronomical evaluation of the system during the first three years of operation, when several cycles of cropping cave been performed in different seasons, all of them in a closed water cycle with the recovery of evapotranspiration and drainage, and with an enhanced concentration Of CO2 in the air (1000 p.p.m.). Production data are given for two autumn and two spring cycles of beans (Phaseolus vulgaris), as well as for one summer cycle of okra (Abelmoschus esculentus). The yield results, together with those of the productivity of water, are compared with the standards for the region and, in the case of one spring cycle of beans (cv. Strike), with a similar crop grown simultaneously in an open greenhouse. Better production, and a much higher efficiency in the use of water is achieved in the closed greenhouse.