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United States Department of Agriculture

Agricultural Research Service

Title: Root Length Measurements of Segments Washed from Soil Cores Without Removal of Extraneous Debris

Authors
item Dowdy, Robert
item Smucker, A - MICHIGAN STATE UNIVERSITY
item Dolan, Michael
item Ferguson, J - MICHIGAN STATE UNIVERSITY

Submitted to: Plant Roots From Cells To Systems
Publication Type: Proceedings
Publication Acceptance Date: September 11, 1995
Publication Date: N/A

Technical Abstract: The greatest constraints to our understanding of root dynamics in agroecological systems has been the laborious tedium associated with accurate measurements of root parameters, eg. root length and diameter. Recently, a technique was presented for fast accurate measurement of the length and diameter of all fragments of corn (Zea mays L.) roots washed from a soil core by analyzing a single image of those roots. Unresolved was the necessity to "hand pick" extraneous organic debris partitioned with live roots during elutriation. This report presents a technique for partitioning live root images from debris via imaging techniques, eliminating "hand pick". The approach assumes that the ratio of length:width for root segments differs greatly from that of included debris. NIH-Image and standard spreadsheet software were utilized to generate length, width, and length:width ratios of all objects in corn root fractions partitioned from 24 soil cores. These parameters were determined for "hand picked" root fractions of the same cores. A 15:1 object length:width ratio was found to represent the best threshold to separate images of roots from those of debris (r**2+0.89). For roots without debris, r**2 between total root length in soil cores determined via NIH-Image, using a 15:1 ratio, and that measured by the line-intersect approach was 0.97. Total root lengths for the same set of samples (roots plus debris) were measured independently. The r**2 between total root length determined in the two laboratories was 0.80. This approach reduces by one-half, the time required (70 min) to accurately determine the total length of roots contained in a soil core.

Last Modified: 10/23/2014
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