Estimation of the crop coefficient Kc for winter crops and pastures in the upper basin of the Sauce Chico river of the Province of Buenos Aires from remote sensors

Obtaining precise evapotranspiration values ​​is a complex task, however Geographic Information Technologies allow us to approximate some parameters for their precise estimation adjusted to local conditions. The objective of this work was to estimate the crop coefficient from the Normalized Difference Vegetation Index (NDVI) of the satellite images, for winter crops and pastures of the upper basin of the Sauce Chico river of the Province of Buenos Aires - Argentina, and compare them with the Kc of bibliography reference. Monthly NDVI values ​​were used, from which plots with winter crops and meadows were identified; Then, through mathematical expressions, the NDVI was related to the Kc of crops and grasslands. Subsequently, the Kc obtained from remote sensors were compared with those published by Food and Agricultura Organization (FAO) and applied to the calculation of crop evapotranspiration. The results of this work approximate specific Kc values ​​for the crop and zonal conditions, which allowed the estimation of the evapotranspiration of crops and pastures to be used at the basin level, and thus contribute to the study of regional hydrological dynamics.