The Use of a Meteorological Station Network to Provide Crop Water Requirement Information for Irrigation Management

Despite of the water use increment for other sectors than agriculture, the water use for irrigation is the main water consumer in global scale. However, irrigation has been pressured by the civil society to improve water use efficiency in agriculture, to prevent water scarcity for human population that grows continuously, mainly in developing areas of the planet. On the other hand, the irrigation practice is considered the main tool to increase water use efficiency, either for increasing crop production or for keeping rural works in the agricultural areas. The water use efficiency can be improved through the adoption of an efficient irrigation management and programming that results in water conservation. Several methods of irrigation management have been developed and used in the last few decades, but the adoption of the majority of then by the irrigated grower was limited by the cost, time of installation, maintenance and local difficulties that the selection of a specific method involves. In arid regions, the decision of "when" and "how much" to irrigate is relatively simple. However, in wet regions when complementary irrigation is used, the irrigation scheduling is a complex task, mainly due to the water added from rainfall events. The Sistema IrrigaTM is basically a service of irrigation management developed by the Federal University of Santa Maria, Brazil. The criteria used by this method to decide the amount of each irrigation application is based on crop parameters of the irrigated crop, soil physical characteristics, meteorological conditions and characteristics of the irrigation 20 Reimar Carlesso , Mirta Teresinha Petry , Celio Trois system and irrigation method, combined with a mathematical model to determine the reference and crop evapotranspiration. This paper describes all factors and parameters used by the Sistema IrrigaTM service, since the data acquisition (plant, soil, weather and irrigation system information), data processing and how the irrigation recommendation is available to the farmers.