A Decision Support System for the Irrigation and Nutrition Management of Tomatoes Cultivated in Low-technology, Plastic-covered Greenhouses

Abstract

Vegetable production in low-technology (low-tech) plastic-covered greenhouses depends on low investment and cheap production methods that prohibit the adoption of expensive technologies. Nevertheless, advanced technology can be developed for this low-tech situation provided that a personal computer (PC) is available and the software is of low cost and specially designed to function without the need for additional expensive hardware. This will encourage the adoption of computer technology in an industry where computer illiteracy is still high. In the present paper, a decision support system for irrigation and fertilizer management of tomatoes [Lycopersicon esculentum (L.) Mill.] is described. The system is comprised of two modules: 1) an irrigation-fertilization consultation module for the management of water and fertilizer supply and 2) a diagnostic expert system module for the identification and rectification of nutritional disorders. Irrigation requirements are defined on the basis of daily evaporimeter readings. Fertilizer schedules are derived from the literature, but modified on the basis of experience gained during previous cultivations. The urgent need for such a management system is indicated by the relatively low quality of vegetable produce currently grown in low-tech greenhouses and the waste of precious water and fertilizer due to over-application by growers, with concomitant damage to the environment. During tests, irrigation was reduced by as much as 30% in comparison with empirical methods. To enable more widespread assessment and to increase its range of application, the software of this system is offered free of charge for evaluation by interested users.