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

Near-infrared spectroscopy and soil physicochemical determinations (pHH2O, organic matter content, total C content, NH4+, total N content, cation-exchange capacity, and base saturation) were used to characterize fire- or wood ash-treated humus samples. The spectroscopic and the soil physicochemical analysis data from the humus samples were used separately to explain observed variations in soil respiration and microbial biomass C by partial least-square regression. The first regression component obtained from the physicochemical and spectroscopic characterization explained 10-12% and 60-80% of the biological variation, respectively. This suggests that information on organic material collected from near-infrared spectra is very useful for explaining biological variations in forest humus.