Partitioning soil respiration: quantifying the artifacts of the trenching method

Total soil respiration ( Rt ) is a combination of autotrophic ( Ra ) and heterotrophic respiration ( Rh ). Root exclusion methods, such as soil trenching, are often utilized to separate these components. This method involves severing the rooting system surrounding a plot to remove the Ra component. However, soil trenching has potential limitations including (1) reduced water uptake in trenched plots that increases soil water content, which is one of the environmental controllers of Rt in many ecosystems, and (2) increased available carbon substrate for Rh caused by recently severed dead roots. We present a methodology that utilizes a bayesian modeling framework to quantify the magnitude of artifacts from a large trenching manipulation experiment. Thus methodology corrects Rh and Ra observations at daily to seasonal time scales. This study finds that the artifacts, due to recently severed roots, persist over a 2 years study period and the artifacts due to altered soil moisture had the greatest impact during drought conditions.