Interpreting the Dependence of Soil Respiration on Soil Temperature and Moisture in An Oasis Cotton Field

Soil respiration is a major component of CO₂ exchange between soil and the atmosphere. The response of soil respiration to climate change is likely to have a significant impact on the CO₂ sink strength of land ecosystems and on future atmospheric CO₂ concentrations. Predicting the response of Rs to climate change requires a thorough understanding of the dependence of this process on soil temperature and water content.

To determine how temperature and moisture affect soil respiration, ZHAO Zhimin et al. took half-hourly measurements of soil temperature, water content, and respiration under plants and between rows in a cotton field of the Aksu National Experimental Station, Xinjiang, China from August to November 2009. They chose the Arrhenius model as the optimum temperature respiration model for this study on the basis of the temperature sensitivity of soil respiration.

To normalize soil respiration, ZHAO et al. calculated the ratios of measured soil respiration values to predicted soil respiration values. They obtained the effect of water content on respiration by analyzing the relationship between normalized soil respiration using the best fit of the Arrhenius function with soil temperature at a 10-cm depth and water content in the 0–10 cm soil layer.

On the basis of these results, ZHAO et al. created a two-dimensional model to describe the dynamics of soil respiration. They found that predictions of soil respiration were better when soil temperature and water content were combined into one equation than when the temperature-respiration equation was used. The effects of soil temperature and water content on soil respiration varied by location (under plants vs. between rows). The result was published in Agriculture, Ecosystems & Environment in March 2013.