ESTIMACIÓN DE ANALITOS DEL SUELO EN LA ALTILLANURA, CON TELEDETECCIÓN SENTINEL-2 Y MODELOS DE REGRESIÓN.

Contextualization: The incorporation of new techniques and technologies to learn about the composition and characteristics of soils used in agricultural production is booming. Free license products such as Sentinel-2 satellite images allow the correlation of soil properties with spectral indices. Knowledge gap: In the agricultural sector, indices calculated from satellite images have focused on vegetation characterization. To a lesser extent, studies have been conducted to evaluate the correlation of those applied to mineralogical prospecting to correlate them with the chemical characteristics of the soil. Purpose: This study was developed with to evaluate the correlation of the indexes of ferric oxides (B11/B8), iron silicates (B12/B11), ferrous iron (B12/8 + B3/4), and alteration (B11/B12), with the content of chemical elements of importance in crop production. Methodology: A crop of 282 hectares was selected in the municipality of Puerto López in the Meta department. Using a Sentinel-2 image, the evaluated indices were calculated. After obtaining the indices, 40 sites were selected for a composite sampling of soils to determine the following characteristics: pH in water (1:1 potentiometric), organic matter (Walkey and Black), P (Bray II), Al (KCl 1N), Ca, Mg, K, and Na (Ammonium Acetate), Fe (DTPA). With the information obtained, a multiple regression analysis was carried out using the “Stepwise” method. The raster layers with the calculated indices were used as independent variables, and the values of the properties determined in the laboratory were used as the variables to predict. Results and conclusions: The evaluated indexes showed a correlation greater than 0.60 with Mg and Ca content. A correlation between 0.40 and 0.60 was found between the indices and organic carbon and Fe content. The calculated regression models revealed fits of 0.54, 0.47, and 0.33 to Mg, Ca, and Fe, respectively. The findings of this research lead to the conclusion that it is possible from Sentinel-2 images to estimate the concentration of elements available to plants in the edaphoclimatic conditions of the Colombian Altillanura. [ABSTRACT FROM AUTHOR]