Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Kadono, Atsunobu; Funakawa, Shinya*; Kosaki, Takashi*
Soil Science and Plant Nutrition, 55(2), p.243 - 251, 2009/04
Times Cited Count：11 Percentile：32.28(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.
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.
Koarashi, Jun; Atarashi-Andoh, Mariko; Ishizuka, Shigehiro*; Kadono, Atsunobu*; Moriya, Koichi*; Nakanishi, Takahiro
no journal, ,
Accelerated release of carbon (C) previously stored in soils is considered one of the most important positive feedbacks from terrestrial ecosystems to the atmosphere in a future warmer world. We used 14C analysis following chemical fractionation to quantify the sizes and turnover times of C pools of Japanese forest soils. The 
C-based approach revealed higher variations of the family of MRTs soil by soil. The size of C pools that cycle slowly on timescales of 100-1000 years strongly correlated with the content of pyrophosphate-extractable Al. In contrast, faster-cycling C pools that turn over within decades showed a negative correlation with mean annual temperature at the sites. Our results suggest that C dynamics in the isolated SOC pools may be regulated by different mechanisms: temperature control on decadal cycling C versus mineralogy control on slower-cycling C, and clearly demonstrate that the forest soils will respond very differently to climate change over the next century.
Koarashi, Jun; Atarashi-Andoh, Mariko; Ishizuka, Shigehiro*; Kadono, Atsunobu*; Moriya, Koichi*; Nakanishi, Takahiro
no journal, ,
Soils are the largest carbon (C) reservoir in terrestrial ecosystems, and may act as both a source and sink of atmospheric CO in response to climate change. Identifying the sizes and turnover times of soil organic carbon (SOC) pools is a crucial step to predicting the fate of soil C. Here, we used a C-based approach to quantitatively understand how much and how long Japanese forest soils store C in their surface horizons. We collected soil samples from deciduous forests, separated the samples into SOC fractions, and then determined their C ratios to estimate mean residence times (MRTs). The MRTs ranged from years to millennia, which revealed a different distribution of MRTs between the soils. We found that the total amount of C correlated positively with the size of the SOC pools cycling on time scales of 
100 years, but poorly with the size of faster-cycling pools. The results suggest that the soils with higher C stocks do not necessarily have higher potential for CO emission.
Koarashi, Jun; Atarashi-Andoh, Mariko; Ishizuka, Shigehiro*; Kadono, Atsunobu*; Moriya, Koichi*; Nakanishi, Takahiro
no journal, ,
no abstracts in English
Koarashi, Jun; Atarashi-Andoh, Mariko; Ishizuka, Shigehiro*; Kadono, Atsunobu*; Moriya, Koichi; Nakanishi, Takahiro
no journal, ,
no abstracts in English
