Observations and modeling of biomass and soil organic matter dynamics for the grassland biome worldwide

Abstract

Century is a model of terrestrial biogeochemistry based on relationships between climate, human management (fire, grazing), soil properties, plant productivity, and decomposition. The grassland version of the Century model was tested using observed data from 11 temperate and tropical grasslands around the world. The results show that soil C and N levels can be simulated to within ±25% of the observed values (100 and 75% of the time, respectively) for a diverse set of soils. Peak live biomass and plant production can be simulated within ± 25% of the observed values (57 and 60% of the time, respectively) for burned, fertilized, and irrigated grassland sites where precipitation ranged from 22 to over 150 cm. Live biomass can be generally predicted to within ±50% of the observed values (57% of the time). The model underestimated the live biomass in extremely high plant production years at two of the Russian sites. A comparison of Century model results with statistical models showed that the Century model had slightly higher r2 values than the statistical models. Data and calibrated model results from this study are useful for analysis and description of grassland carbon dynamics, and as a reference point for testing more physiologically based models prediction's of net primary production and biomass. Results indicate that prediction of plant and soil organic matter (C and N) dynamics requires knowledge of climate, soil texture, and N inputs.

Present state of global wetland extent and wetland methane modelling: methodology of a model inter-comparison project (WETCHIMP)

“…This is an important feature of modelling realistic changes in land surface primary production, which depends on, and should be in line with, realistic biological and anthropogenic nitrogen fixation rates (Hungate et al, 2003). In SDGVM, litter production influences soil carbon and nitrogen pools via the Century soil nutrient cycling model (Parton et al, 1993), which in turn feedback to influence the primary production of vegetation; details are provided elsewhere (Beerling and Woodward, 2001). …”

Carbon dynamics and land-use choices: building a regional-scale multidisciplinary model

“…This model, developed at Colorado State University (Parton et al, 1987), simulates C, N, P, and S cycles in various ecosystems, including pastures, forests, crops, and savannas, and can model the impacts of management practices such as fertilization, and cultivation, as well as natural disturbances such as fire and hurricane (Parton et al, 1987(Parton et al, , 1993. This model has also been tested extensively against field measurements from various ecosystems around the world (e.g., Parton et al, 1993;Schimel et al, 1994;Smith et al, 1997) and used for biogeochemical simulation purposes at the regional, continental, and global scales (e.g., Schimel et al, 1994;VEMAP, 1995;Schimel et al, 1997). CENTURY has already been adapted for simulating nitrogen and C dynamics in various ecosystems in the Atlantic lowlands of Costa Rica, including primary forests, secondary forests, pastures, and banana plantations (Liu et al 1999, Reiners et al 2002.…”

Testing the modified Rothamsted Carbon Model for paddy soils against the results from long-term experiments in southern China

“…Soil organic matter (SOM) turnover models are being used to assess the regional or global dynamics of soil organic carbon (SOC) (e.g., Parton et al 1993;Falloon et al 1998). Many models have been published, such as the Rothamsted Carbon Model (RothC) (Coleman and Jenkinson 1999), CENTURY (Parton et al 1987), and DNDC (De-Nitrification and De-Composition model; Li et al 1992a, b).…”