Estimativa do coeficiente de cultura (Kc) do arroz por sensoriamento remoto na microbacia hidrográfica do arroio Cambaí em Itaqui RS

Abstract

The municipality of Itaqui obtained in the agricultural year 2013/14 one of the largest areas planted to rice, representing approximately 10% of the rice production of RS. The rice crops to be irrigated by surface flooding have an irrigation efficiency of around 40%, which may lead the farmer to have an abundant water supply as 60% of water inserted into the crop is lost by evaporation and seepage; which explains the importance of knowing the quality and quantity of water use for crop development aspects. Based on methodologies that use remote sensors (meteorological and satellite imagers) and geographic information systems (GIS), it is possible to estimate the crop evapotranspiration, which is the actual use of water in farming, and is possible to identify the early stage culture and its evolution until the end of your cycle, you can check if the culture is in full force, through on-site evaluation of each image. These observations may be identified through the Normalized Difference Vegetation Index (NDVI), which is an indicator of quality of vegetation, with which it can be estimated actual crop evapotranspiration (ETc), evaporation of water from farming coupled with perspiration of culture and thus its computed crop coefficients (Kc) for each plant assessment (controlled water unit), which is the focus of this work concerned. So with the methodologies adopted using the NDVI, it is possible to identify the development cycle of the rice crop, the crop evapotranspiration (ETc) and their respective Kc, the assessed dates (dates of passage of Landsat 8). The crop coefficients were found the value of 1.0 for the initial stage of culture, 1.25, and 0.6 for intermediate stage to the final stage of crop development.