The Brazilian economy is highly dependent on agricultural activities, which by its side is subject to a highly variable weather conditions. So in order to improve the agricultural activities in Brazil it must be considered that the farmers need a mechanism to help them to cope with adverse weather or adverse environmental conditions. Such a mechanism should take in consideration the different ecological zones and social differences exiting in the Brazilian Agriculture.
Therefore, The Decision Support System for Agriculture in Brazil (SISDA), was developed taking into account the great diversity in technology and education level of Brazilian farmers and also on their environment, but also considering that the first challenge was to conceive a country-wide decision support system. SISDA has in its file information on soil characteristics and climate daily information of around 600 weather station and over 8500 cities in Brazil. It also has information on crop disease and characteristics(degree-day, crop development, water use). The data base is spatially structured and will provide for any particular location in Brazil information on climate conditions, soil and crops and plus their interactions. SISDA outputs comprises: length of the growing season, potential evapotranspiration, rainfall probability, dry spell probability, probability of disease occurrence and soil water availability. It provides to the user two main options: management (day-to-day decision) and Simulation (scenarios). SISDA was developed using DELPHI 2.0 and it is a user-friendly system in both inputs and outputs. SISDA had the participation of experts from different disciplines: agricultural meteorology, irrigation management, irrigation engineering, soil science, agronomy, plant pathology and computer science.