Fate and Transport of Nitrogen and Carbon in a Soil with pH Buffering based on a SOM Decay Model Using the HP1 Code.

Abstract

In order to predict fate and transport of nitrogen and carbon in a soil with pH buffering as a result of decomposition of soil organic matters (SOMs), we modified a coupled nitrogen and carbon cycling model based on the LEACHM code (Hutson, 2005) to include dissolution of NH₃ and CO₂ as well as proton reactions in nitrification using the PHREEQC program. The pH buffering was described with the variable charge model. The SOM decay model were linked with water flow, solute transport, and gas diffusion in HYDRUS-1D using the HP1 code. Various nitrogen and carbon scenarios as a result of application of organic matters to variable-saturated Andisol and Sand under a nonisothermal condition were demonstrated.