SciELO - Scientific Electronic Library Online

 
vol.70 issue3Selection of the application site and phenological stage of cotton plants to ramulosis inoculation agentCharacterization and classification of archaeological dark earths from the Middle Madeira River Region author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Bragantia

Print version ISSN 0006-8705

Abstract

DEMATTE, José A. M.; BORTOLETTO, Marco Antonio Melo; VASQUES, Gustavo M.  and  RIZZO, Rodnei. Quantification of soil organic matter using mathematical models based on colorimetry in the Munsell color system. Bragantia [online]. 2011, vol.70, n.3, pp. 590-597.  Epub Sep 30, 2011. ISSN 0006-8705.  http://dx.doi.org/10.1590/S0006-87052011005000006.

This study aimed to derive mathematical models to predict the soil organic matter content based on soil color obtained by a colorimeter in the Munsell color system. A total of 907 soil samples were collected in the region of Porto Grande (Amapá, Brazil) and analyzed in the laboratory for chemical properties, particle size distribution and color of dry and wet samples. The Munsell color components value and croma obtained using a colorimeter were used to predict soil organic matter content based on stepwise multiple linear regression. Models derived using all samples had R2 of 0.66 for wet samples and 0.56 for dry samples, respectively, when validated using independent samples. It was possible to improve the models by separating the samples by soil class or texture. The models derived using colors obtained from wet samples were systematically better than those based on dry samples. Among soil classes, best results were obtained for Argissolos (Ultisols) and Latossolos (Oxisols), both having an R2 of independent validation of 0.73 (wet sample). For texture, best results were obtained for very clayey soils, with an R2 of validation of 0.81 (wet sample). The soil organic matter prediction models based on soil color have simplicity and potential to be used in the laboratory and in the field with quick and unnecessary chemical products, especially for Ultisols and Oxisols of clayey texture.

Keywords : texture; soil class; soil color; colorimeter.

        · abstract in Portuguese     · text in Portuguese     · pdf in Portuguese