Journal Article

Improved scaling of minirhizotron data using an empirically-derived depth of field and correcting for the underestimation of root diameters

Pritchard, Seth G., Beidler, Katilyn V., Taylor, Benton N., Strand, Allan E.

2014

Overview

Background and aims Accurate data on the standing crop, production, and turnover of fine roots is essential to our understanding of major terrestrial ecological processes. Minirhizotrons offer a unique opportunity to study the dynamic processes of root systems, but are susceptible to several measurement biases. Methods We use roots extracted from minirhizotron tube surfaces to calculate the depth of field of a minirhizotron image and present a model to correct for the underestimation of root diameters obscured by soil in minirhizotron images. Results Non-linear regression analysis resulted in an estimated depth of field of 0.78 mm for minirhizotron images. Unadjusted minirhizotron data underestimated root net primary production and fine root standing crop by 61 % when compared to adjusted data using our depth of field and root diameter corrections. Changes in depth of field accounted for >99 % of standing crop adjustments with root diameter corrections accounting for <1 %. Conclusions Our results represent the first effort to empirically derive depth of field for minirhizotron images. This work may explain the commonly reported underestimation of fine roots using minirhizotrons, and stands to improve the ability of researchers to accurately scale minirhizotron data to large soil volumes.

• Publisher: Springer,Springer Netherlands,Springer Nature B.V
• Subject: Agricultural soils / Agrology / Agronomy. Soil science and plant productions / Animal, plant and microbial ecology / Biological and medical sciences / Biomass / Biomedical and Life Sciences / Carbon cycle / Carbon sequestration / Crops / Diameters / Ecology / Environmental aspects / fine roots / Forest soils / Fundamental and applied biological sciences. Psychology / General agronomy. Plant production / Life Sciences / net primary productivity / Plant Physiology / Plant roots / Plant Sciences / Plant-soil relationships / Plants / Primary production / Regression analysis / Regular Article / Rhizobium / Rooting depth / Roots / Roots (Botany) / soil / Soil depth / Soil fertility / Soil microbiology / Soil research / Soil rooting depth / Soil Science & Conservation / Soil-plant relationships. Soil fertility / Soil-plant relationships. Soil fertility. Fertilization. Amendments / Studies / Wetland soils