Climate factors mediate soil respiration dynamics in Mediterranean agricultural environments: an empirical approach

Abstract

Soil CO2 emissions, the result of soil respiration processes, may be essential in climate change modelling. The complex phenomenon of soil respiration is regulated by a range of mainly climate-related environmental factors. We tested the latest published empirical models in a field experiment in an agricultural soil under Mediterranean conditions. Soil respiration was monitored biweekly with a portable infrared gas analyser, and climate features were monitored for 1 year (2010–11). An additional rewetting assay (watering the soil) was done at the end of the experiment in summer when the soil water content was dry. We tested different approaches to represent the simple effect of climate factors on soil respiration and found Gaussian models to be the best. We also tested the most recent models designed to represent the synergic effects of climate factors, and our modification of the Martin and Bolstad model showed the best coefficient of determination. The results suggest that linear approaches and the use of a fixed Q10 value should be revised to represent climate and soil respiration relations, especially in high-variability environments where soil respiration variability is controlled by soil temperature and moisture interactions, while precipitation pulses induce CO2 emission peaks. Finally, our results showed that the influence of soil temperature and moisture on soil respiration is lower under Mediterranean conditions than in temperate climate types.