DOI: 10.4211/hs.b83e679a793240348f9699c9b56334ec
title: A Soil Structure-Based Modeling Approach to Heterotrophic Respiration

description: This resource includes the Python scripts used to generate figures for the manuscript entitled " A Soil Structure-Based Modeling Approach to Heterotrophic Respiration." The folder soil-heterogeneity-respiration contains following Jupyter notebooks with their description:

Figure 1.ipynb file contains the code used to draw Figure 1 showing CDF of truncated gamma aggregate size distribution compared to the literature data. 
Figure 2.ipynb file contains the code used to draw Figure 2 showing how the model captured the effect of land uses on SOC in different aggregate size classes.
Figure 3.ipynb file contains the code used to draw Figure 3 depicting the relationship of different biophysical factors controlling the soil microbial respiration at a relative soil moisture content. 
Figure 4.ipynb file contains the code used to draw Figure 4 depicting moisture-respiration relationship for different heterogeneity scenarios. 
Figure 5.ipynb file contains the code used to draw Figure 5 depicting moisture-respiration curves for homogeneous vs heterogeneous scenarios. 

To find the updated version of the codes, visit the GitHub link: https://github.com/Achla-Jha/soil-heterogeneity-respiration.git 

The abstract of the manuscript: 

Soil microbial communities play a pivotal role in controlling soil carbon cycling and its climate feedback. Accurately predicting microbial respiration in soils has been challenged by the intricate resource heterogeneity of soil systems. This makes it difficult to formulate mathematical expressions for carbon fluxes at the soil bulk scale which are fundamental for soil carbon models. Recent advances in characterizing and modeling soil heterogeneity are promising. Yet they have been independent of soil structure characterizations, hence increasing the number of empirical parameters needed to model microbial processes. Soil structure, intended as the aggregate and pore size distributions, is, in fact, a key contributor to soil organization and heterogeneity and is related to the presence of microsites and associated environmental conditions in which microbial communities are active. In this study, we present a theoretical framework that accounts for the effects of microsites heterogeneity on microbial activity by explicitly linking heterogeneity to the distribution of aggregate sizes and their resources. From the soil aggregate size distribution, we derive a mathematical expression for heterotrophic respiration that accounts for soil biogeochemical heterogeneity through measurable biophysical parameters. The expression readily illustrates how various soil heterogeneity scenarios impact respiration rates. In particular, we compare heterogeneous with homogeneous scenarios for the same total carbon substrate and microbial biomass and identify the conditions under which respiration in heterogeneous  soils (soils having non-uniform distribution of carbon substrate and microbial biomass carbon across different aggregate size classes) differs from homogeneous soils (soils having uniform distribution of carbon substrate and microbial biomass carbon across different aggregate size classes). The proposed framework may allow a simplified representation of dynamic microbial processes in soil carbon models across different land uses and land covers, key factors affecting soil structure.