11:00 AM - 1:00 PM
[ACG39-P04] Development of terrestrial ecosystem phosphorus cycle model
Keywords:phosphorus cycle, phosphorus limitation, process-based model
Phosphorus circulates throughout the earth as an essential nutrient element and plays significant roles greatly on plant growth, so that its shortage can limit plant growth (Darcy, et al., 2018). Phosphorus limitation might suppress the plant growth especially in temperate zone and tropical zone (Du et al, 2020), even under the favorable condition for the plant growth by high CO2 concentration and high temperature predicted in future. To estimate how much phosphorus limitation would accelerate climate change, the process-based model is necessary for accurately estimating the circulation of phosphorus as well as carbon and nitrogen.
We introduced phosphorus cycle module (Wang, 2010) into original VISIT (Ito and Inatomi, 2012) to simulate phosphorus, carbon and nitrogen cycles (VISIT-CNP). Its accuracy was validated with observational data at Thurston and Kokee in Hawaii (Vitousek, 2004). These sites have almost same climate (annual average temperature : 15.5℃, annual precipitation : 2500mm in both site), altitude (1176m in Thurston, 1134m in Kokee), and vegetation (Metrosideros polymorpha). However, their soil substrate ages are largely different (300 years in Thurston, 4.1 million years in Kokee) which lead to nitrogen limitation in Thurston and phosphorus limitation in Kokee. Reanalysis climate, NOAA-CIRES (https://psl.noaa.gov/data/gridded/data.20thC_ReanV3.pressure.html), and ground observational data of NOAA-NCEI (https://www.ncdc.noaa.gov/cdo-web/datasets) were used as an input at daily time step from 1948 to 2010.
VISIT-CNP could represent the content of carbon, nitrogen, and phosphorus in five pools (leaf, wood, root, litter, and soil organic matter) with high accuracy (determination coefficients between estimated and observed values; carbon, nitrogen, and phosphorus are 0.80, 0.87, 0.92 in Thurston, 0.70, 0.95, 0.68 in Kokee, respectively). We also simulated the case with reduced phosphorus input in Thurston from 63 to 0.2 gP m-2 year-1, which was resulted in slight decrease of net primary production from 891 to 869 gC m-2 year-1. Estimated phosphorus pools in both sites indicated that soil organic matter pool was the largest storage in both sites as 29.13 gP m-2 in Thurston and 66.62 gP m-2 in Kokee, and absorbed phosphorus pool was the second largest as 7.39 gP m-2 in Thurston and 59.50 gP m-2 in Kokee.
We introduced phosphorus cycle module (Wang, 2010) into original VISIT (Ito and Inatomi, 2012) to simulate phosphorus, carbon and nitrogen cycles (VISIT-CNP). Its accuracy was validated with observational data at Thurston and Kokee in Hawaii (Vitousek, 2004). These sites have almost same climate (annual average temperature : 15.5℃, annual precipitation : 2500mm in both site), altitude (1176m in Thurston, 1134m in Kokee), and vegetation (Metrosideros polymorpha). However, their soil substrate ages are largely different (300 years in Thurston, 4.1 million years in Kokee) which lead to nitrogen limitation in Thurston and phosphorus limitation in Kokee. Reanalysis climate, NOAA-CIRES (https://psl.noaa.gov/data/gridded/data.20thC_ReanV3.pressure.html), and ground observational data of NOAA-NCEI (https://www.ncdc.noaa.gov/cdo-web/datasets) were used as an input at daily time step from 1948 to 2010.
VISIT-CNP could represent the content of carbon, nitrogen, and phosphorus in five pools (leaf, wood, root, litter, and soil organic matter) with high accuracy (determination coefficients between estimated and observed values; carbon, nitrogen, and phosphorus are 0.80, 0.87, 0.92 in Thurston, 0.70, 0.95, 0.68 in Kokee, respectively). We also simulated the case with reduced phosphorus input in Thurston from 63 to 0.2 gP m-2 year-1, which was resulted in slight decrease of net primary production from 891 to 869 gC m-2 year-1. Estimated phosphorus pools in both sites indicated that soil organic matter pool was the largest storage in both sites as 29.13 gP m-2 in Thurston and 66.62 gP m-2 in Kokee, and absorbed phosphorus pool was the second largest as 7.39 gP m-2 in Thurston and 59.50 gP m-2 in Kokee.