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Techniques such as near infrared spectroscopy (NIR) can be used to identify classes and properties of soils with good precision. The aim of this study was to calibrate models to predict the content of clay, silt and sand of a Typic Hapludox by NIR spectroscopy. The study was carried out in the Carimagua Experimental Station located in the municipality of Puerto Gaitán, Meta, Colombia. A grid design was used, 1200 samples were collected in an area of 5100 ha. The development of the models have made by partial least squares regression. A low representatively models were obtained for sand and silt contents, with values of R2 (0.41 and 0.34, respectively).The clay model  content showed a high R2 (0.76). For the clay was possible the development of similar digital maps and digital spectrum maps . The results for the clay content indicate that laboratory analysis  can be substituted, in large part by spectral models. In the case of sand and silt, in the future,  it would be convenient to improve the model  for substituting the laboratory analysis  for this class of soil.

The characterization of soil properties through laboratory analysis is an essential part of the diagnosis of the potential use of lands and their fertility. Conventional chemical analyzes are expensive and time consuming, hampering the adoption of crop management technologies, such as precision agriculture. The aim of the present paper was to evaluate the potential of near-infrared (NIR) diffuse reflectance spectroscopy for the prediction of the carbon and nitrogen of Typic Hapludox. In the A and B horizons, 1,240 samples were collected in order to determine the total carbon (TC) and nitrogen (TN) contents, obtain the NIR spectral curve, and build models using partial least squares regression. The use of diffuse reflectance spectroscopy and statistical techniques allowed for the quantification of the TC with adequate models of prediction based on a small number of samples, an residual prediction deviation RPD greater than 2.0, an R2 greater than 0.80 and a low root mean square error RMSE. For TN, models with a good level of prediction were not obtained. The results based on the NIR models were able to be integrated directly into the geostatistical evaluations, obtaining similar digital maps from the observed and predicted TC. The use of pedometric techniques showed promising results for these soils and constitutes a basis for the development of this area of research on soil science in Colombia.

Este documento presenta una perspectiva general del estado actual del conocimiento de la degradacion del suelo por la erosion hidrica, con enfasis en su evaluacion y representacion cartografica. Se incluyen fundamentos y aspectos historicos de mayor relevancia y se explican las diversas categorias metodologicas empleadas en su estudio y evaluacion, con algunas experiencias de aplicacion. Se destaca la importancia del uso de los sensores remotos y los Sistemas de Informacion Geografica (SIG). Sobre los primeros se discute el uso de las imagenes satelitales, de importante apoyo cualitativo y cuantitativo para investigaciones y evaluaciones de los procesos de erosion, modalidades que permiten visualizar y hacer un seguimiento de dichos procesos en tiempo y espacio. Respecto a los SIG, se evidencian sus limitaciones y potencialidades dada su gran capacidad de representacion cartografica, analisis y ahorro de tiempo. Los SIG han permitido facilitar procesos laboriosos vinculados a la representacion cartografica producto de los estudios comunmente relacionados al tipo, condicion, riesgos actuales y potenciales de la erosion hidrica, mapeados a diferentes escalas.