Response of soil carbon to historical land use changes in the US Great Plains: effects of matching soil carbon fractions with ecosystem model of active, slow and passive pools
Abstract
The Great Plains region of the United States has undergone extensive land cover land use change (LCLUC) since the early 19th century due to an increase in agricultural practices of varying intensities. The LCLUC together with climate change have dramatically altered the soil carbon stocks in the US Great Plains. Although the effects of climate and LCLUC on soil carbon stocks have been well evaluated in this region, there is still a limited understanding of how these changes have altered the distribution of particulate organic carbon (active; POC), humus or mineral-protected organic carbon (slow; HOC) and resistant organic carbon (passive; ROC) pools. Here, we utilize carbon fractions predicted through a combination of drift spectroscopy and random forest modeling to modify and calibrate the DAYCENT biogeochemical model against fractional distribution of SOC. We then performed two historical simulations: 1) default DAYCENT; and 2) modified DAYCENT to estimate changes in SOC and their fractions during the historical period (1895-2016). We compared the SOC change between the two simulations to better understand the drivers, causes and uncertainty associated with estimates of soil carbon changes in the Great Plain region. We conclude our analysis with a discussion on the potential of modified DAYCENT simulation in predicting the changes in POC, HOC and ROC in the 21st century using different climate and land use scenarios.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.B21K2366D
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 0486 Soils/pedology;
- BIOGEOSCIENCES;
- 1622 Earth system modeling;
- GLOBAL CHANGE