Viabilidade ecônomica da irrigação por pivô central nas culturas de soja, milho e tomate

Abstract

The economic viability of an agricultural project with irrigation is influenced by the implementation costs and system maintenance. They vary with the water capacity applied by irrigation system and the water applied in the crop cycle. The objective of this study was to verify the economic viability of irrigation center pivot on soybean, corn and tomato crops, for different evapotranspiration levels consequent variation in hydraulic design and irrigation management. An area irrigated by center pivot of 80.78 ha was considered for the study, simulating the rotary cultivation of soybeans, corn, and tomatoes (2.5 crop per year), in the region of Cristalina-GO, with useful life of irrigation system of 30 years. It was considered ETo historical average in the region, as well as seven other simulated values (ETo 4 to 7 mm per day). The AMAZONSAF-EMBRAPA software was used for the calculation of financial indicators based on technical coefficients of cultivation in the region. It was verified that on average 50% of the total cost of production are with fertilizers, fertilization and phytosanitary control, and only 8% with irrigation (4% of investment with hydraulic equipment + dam and 4% cost with energy). The 77% variation in water requirement caused a reduction of only 2.4% in the total production cost. This reveals viability of the project, even with variation ETo level, with a benefit/cost ratio of 2.1 and the possibility to pay investments in 2 years, with average profitability of R$ 6,000 ha-1 year-1.