Location: Livestock and Range Research LaboratoryTitle: A common soil handling technique can generate incorrect estimates of soil biota effects on plants
Submitted to: New Phytologist
Publication Type: Other
Publication Acceptance Date: 11/25/2015
Publication Date: 2/2/2016
Citation: Reinhart, K.O., Rinella, M.J. 2016. Letter: A common soil handling technique can generate incorrect estimates of soil biota effects on plants. New Phytologist. 210:786-789.
Interpretive Summary: • Problem- Many experimental designs are used to quantify the effect of soil biota on plants. Results of these experiments may be highly sensitive to how soils containing the biota are processed and analyzed. • Accomplishment- Our results illustrate that proper soil handling technique is essential for robust tests of hypotheses on plant-microbe interactions. Faulty methods (i.e. mix soil samples) are prone to generating erroneous results. Scientists should avoid unnecessary mixing of soil samples gathered from different experimental units (e.g. sites, plots).
Technical Abstract: Several plant-soil biota (PSB) studies were recently published in high profile journals that used the suspect “mixed soil sampling” methodology. To explore the extent to which mixing field samples (i.e. employing mixed soil sample designs) can generate erroneous conclusions, we used real data to parameterize a system for simulating results for experiments based independent vs. mixed soil samples per greenhouse container. We quantified the probability of type I statistical errors for each soil handling technique. We found that correct methods had predicted levels of type I statistical errors (ca. 5%). Incorrect methodology (mixed soil samples) had unacceptably high levels of type I statistical errors (ca. 50%). Our simulation highlights how robust PSB experiments require proper soil handling technique.