SEBAL, Actual evapotranspiration, Landsat-8, statistical inference
Agricultural and livestock production is influenced by different climatic factors and international demand. Currently, livestock has an important role in the country's economic activity, and as a result of this influence, there is a need to rethink the management steps based on the application of new techniques and technological tools in the management of these areas. The present work presents an evaluation of the biometric conditions and the processing of orbital images to obtain the vegetation indexes of a pasture area located in the municipality of Cachoeiras de Macacu, Rio de Janeiro. For the biometric characterization, both the destructive and the non-destructive method and the orbital images of the Landsat-8 (L8) and Sentinel-2 (S2) satellites were considered. In the campaigns, the leaf area index (IAF) was estimated with the use of the ceptometer and height verification for the external and internal area, in the destructive method adopted in three campaigns the external vegetation was cut at ground level and taken to the laboratory. The orbital images were selected considering the least interference from clouds, pre-processed and manipulated algebraically with geoprocessing tools. The meteorological variables to characterize the environmental conditions of the place were registered by a micrometeorological station installed in the area and the precipitation variable registered by a meteorological station located in the vicinity. The IAF presented an average of 2.10, with a minimum value of 0.68, and a maximum value of 5.00, while in the internal area the average was 2.72, with a minimum value of 1.31 and a maximum of 5.31 . The height of the vegetation in the external area showed an average of 29.2 cm, with a maximum value of 75 cm and a minimum of 8 cm, for the internal area an average of 48.41 cm was found, with a maximum value of 90 cm and a minimum of 12 cm. For L8 images the NDVI (Normalized Difference Vegetation Index) ranged from 0.61 to 0.83, SAVI (Soil-Adjusted Vegetation Index) from 0.32 to 0.68 and IAF with values between 0.52 and 4.56 , for S2 the variation of NDVI was 0.58 to 0.79, SAVI with 0.29 to 0.61 and IAF of 0.42 and 2.17. The study showed that the results show seasonal behavior, indicating that periods with greater availability of water and solar energy in the environment favor the development of vegetation. Monitoring becomes an important tool to assist in the knowledge of seasonal dynamics, providing information for pasture management projects.