The objective of this study was to study the effects of soil macrofauna on physical and chemical attributes and spectral reflectance of an Oxisol, Ultisol and Vertisol in Piracicaba (SP), Brazil. Along a topossequence, the soil aggregates produced by ants (Atta sp.), termites (Cornitermes cumulans) and earthworms (Pontoscolex corethrurus), were collected and compared with the control soil without recent visible animal activity. Soil chemical analysis and granulometry were carried out. The soil spectral behavior was determined in laboratory with a spectroradiometer between 400 and 2500 nm. The earthworm casts had 2 to 3 times more phosphorus and 30 to 50% greater increase in the organic matter content than the soil surface. The termite and ant aggregates showed similar chemical composition compared with the subsurface soil layer. The spectral reflectance of the biological aggregates changed according to their chemical composition and animal activity depth. In the earthworm case, the spectral curves were similar to the soil surface. In the termite and ant structures, chemical composition and spectral behavior corresponded to subsurface soil layer. The spectral curves of the randomly collected soil surface samples can show significant variations in conformity with fauna groups predominating the site and animal activity intensity.
spectroradiometry; fungus-growing ants; termites; earthworm; soil fauna; remote sensing