NEAR-INFRARED CHARACTERISTICS OF FOREST HUMUS ARE CORRELATED WITH SOIL RESPIRATION AND MICROBIAL BIOMASS IN BURNT SOIL

Near-infrared spectroscopy and soil physicochemical determinations (pH H2O, organic matter content, total C content, NH4+, total N content, c ation-exchange capacity, and base saturation) were used to characteriz e fire- or wood ash-treated humus samples. The spectroscopic and the s oil physicochemical analysis data from the humus samples were used sep arately to explain observed variations in soil respiration and microbi al biomass C by partial least-square regression. The first regression component obtained from the physicochemical and spectroscopic characte rization explained 10-12% and 60-80% of the biological variation, resp ectively. This suggests that information on organic material collected from near-infrared spectra is very useful for explaining biological v ariations in forest humus.