Using an economic criteria to support agricultural decisions has been the subject of various scientific papers in the irrigation area, providing an increase in security on the adoption of management practices, in order to maximize the return. This work presents a methodology to quantify the economic irrigation time for furrow irrigation, based on the net income optimization. The proposed methodology may be applied for any crop based on: a) the water-yield function for the growing season, b) duration of each phenological phase with respective Kc values, c) information about the costs involved in the cultivation process. The model was applied for processing tomato crop and the results showed that the maximum net income was obtained when only the initial 70 m of the furrow received the irrigation water depth required by the crop, being the remaining 30 m under water deficit conditions, resulting in a net income of R$ 354.00 ha-1. The use of this model optimizes the water availability when the cubic meter of water is charged.
processing tomato; irrigation efficiency; net income
