Comparação de métodos de determinação de carbono orgânico no solo

Abstract

Organic matter is an essential component for soil fertility and for maintaining biodiversity. Currently, different methodologies for the determination of organic carbon in soils have been used without, however, taking into account the risks they may pose to the environment and the high cost of carrying out their analyses. In this way, there is a need to test the methods, in order to find a method that is less polluting, low cost, practical and efficient. Thus, the objective of this work was to compare three methods of determination of organic carbon in an Oxisol submitted to different managements. The work was carried out with soils from an experimental area of ​the Experimental Farm of the Federal University of Grande Dourados (FAECA), located in the municipality of Dourados, in addition to the collection of soil samples under native vegetation of an Atlantic Forest fragment adjacent to FAECA. Sixteen composite samples were collected from the 0-20 cm layer. A composite sample is the combination of five simple samples. Soil carbon contents were determined by wet combustion methods - titration and spectrophotometer, and dry combustion - muffle. Data were submitted to analysis of variance and subsequently to Tukey's test (p≤0.10). The spectrophotometer and muffle methods tend to overestimate the organic carbon contents compared to the titration method. There was no correlation between the methods studied, indicating the impossibility of using them to replace the reference method, that of titration.