The Modeling of the dynamics of soil organic matter in the Eurasian steppe

Kadono, Atsunobu; Funakawa, Shinya*; Kosaki, Takashi*

For better understanding of the terrestrial SOM dynamics and its modelling, following studies were conducted: (1) to determine the factors that affect the amounts of labile and recalcitrant SOM in different ecosystems, and (2) to offer a simple process-based model with measurable SOM pools that describe in situ SOM dynamics in natural grassland ecosystems. According to the relationship between potentially mineralizable C (PMC) and soil properties in forty-one surface soils collected in Ukraine and Kazakhstan, a SOM dynamics model was constructed using parameters including the PMC, net primary productivity (NPP) and soil respiration on a daily time. Measured soil respiration in Ukraine from 2002 to 2004 was well estimated by the SOM model. These results suggested that the proposed model successfully simulated the decomposition processes of PMC in natural grassland ecosystems.