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United States Department of Agriculture

Agricultural Research Service

Title: A Method to Separate Plant Roots from Soil and Analyze Root Surface Area

Authors
item Benjamin, Joseph
item Nielsen, David

Submitted to: Plant and Soil
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 26, 2004
Publication Date: December 1, 2004
Citation: Benjamin, J.G., Nielsen, D.C., 2004. A method to separate plant roots from soil and analyze root surface area. Plant and Soil Journal. 267:225-234.

Interpretive Summary: Soil management practices often affect crop production by changing the soil environment. The study of management effects on crop production requires a knowledge of these effects on plant roots. Separating living plant roots from organic debris and previous years' roots is tedious and time consuming. The analysis of root length and/or surface area using manual techniques also tends to be slow. To simplify the separation of roots from soil, we developed a root washer that can accommodate relatively large soil samples for washing. The root washer has a rotary design and will accommodate up to 24 samples (4" dia. by 9" long) at one time. A flat-bed scanner was used to digitize an image of the roots from each sample and a grid system with commercially-available image analysis software was used to analyze each sample for root surface area. Comparisons were made between "dirty" samples containing the roots and all the organic debris contained in the sample and "clean" samples where the organic debris was manually removed from each sample. We found that manually separating the roots and debris was required only in very dirty samples where the amount of non-root debris was greater than 20% of the projected image area. These techniques reduced the time needed to gather accurate information on root surface area to about 1 h per sample.

Technical Abstract: Analysis of the effects of soil management practices on crop production requires a knowledge of these effects on plant roots. Much time is required to wash plant roots from soil and separate the living plant roots from organic debris and previous years' roots. We developed a root washer that can accommodate relatively large soil samples for washing. The root washer has a rotary design and will accommodate up to 24 samples (100 mm dia. by 240 mm long) at one time. We used a flat-bed scanner to digitize an image of the roots from each sample and used a grid system with commercially-available image analysis software to analyze each sample for root surface area. Comparisons were made between "dirty" samples containing the roots and all the organic debris contained in the sample and "clean" samples where the organic debris was manually removed from each sample. We found that manually separating the roots and debris was required only in very dirty samples where the amount of non-root debris was greater than 20% of the projected image area.

Last Modified: 11/28/2014
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