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Kadono, Atsunobu; Funakawa, Shinya*; Kosaki, Takashi*
Soil Science and Plant Nutrition, 55(2), p.243 - 251, 2009/04
Times Cited Count：11 Percentile：29.87(Plant Sciences)To understand the dynamics of soil organic matter (SOM) in humid Asia, several properties were tested to estimate the amounts of potentially mineralizable carbon (PMC) and nitrogen (PMN) as well as recalcitrant carbon (ROC) and nitrogen (RON). Eighty-nine surface soil samples were collected in Thailand, Indonesia and Japan from cropland and forest ecosystems. The fresh soils were incubated under constant conditions, and the CO
and the mineral N from the soils were monitored. PMC and PMN were determined by fitting models to the cumulative curves of the emitted C and N. ROC and RON were determined by the subtraction of PMC and PMN from TC and TN, respectively. Using multiple regression analysis with the stepwise method, PMC and PMN was well estimated by carbon and nitrogen content of light fraction (LFC and LFN) and clay content, while ROC and RON were estimated by LF-OM, amorphous materials and clay content, suggesting the importance of parent materials in this region.
Nakao, Atsushi*; Yoshida, Takahiro*; Ozaki, Takuo; Onuki, Toshihiko; Funakawa, Shinya*; Kozaki, Takashi*
Journal of Nuclear and Radiochemical Sciences, 6(1), p.107 - 110, 2005/07
Cs accumulation by Pseudomonas fluorescens was examined under conditions of growth and resting to elucidate the interaction between Cs and bacteria. In the growth condition, P. fluorescens did not accumulate Cs irrespective of the presence of K. In the resting condition, the cells quickly adsorbed approximately 5 
mol Cs/gcell dry-weight and subsequently released approximately 90 % of the adsorbed Cs with 1 M CH
COONH
. The amount of Cs adsorption by cells of P. fluorescens varied with changing pH and ionic strength of the solution. These results indicate that Cs accumulation by P. fluorescens occurs mainly by reversible adsorption on the cell walls, but not by intracellular accumulation under nutrient conditions.
Kadono, Atsunobu; Funakawa, Shinya*; Kosaki, Takashi*
no journal, ,
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.
