Tuesday, 8 November 2005
4

A Comparison of 3 Computer Based Root Diameter Measurement Systems – Efficacy with Diameters Less Than 0.5 MM.

Richard Zobel, USDA-ARS-AFSRC, 1224 Airport Rd., Beaver, WV 25813-9423

Research with fine roots (<0.5 mm diameter) requires either a high tolerance for tedium or very efficient computer software, and often both. It was our intent to test the following hypothesis: When plant root systems are challenged with nutrient deficiencies, the root system responds by increasing the total length of the finest roots relative to total root length (as predicted with SRL (specific root length) analysis). Testing this hypothesis with Orchardgrass requires a minimum resolution of 75 pixels per mm (75 p/mm about 2000 dpi). We developed both a digital camera and a scanner system that could handle 100 p/mm. When we analyzed the images, we found that one of the major computerized root analysis systems introduced artifacts into the results when used at scanning resolutions above 25 p/mm (>600 dpi). These artifacts are present at lower resolutions, but of little consequence. In light of this result, five different computer based systems were evaluated. A comparison of three of these will be presented.

Handout (.pdf format, 341.0 kb)
Handout (.ppt format, 1935.0 kb)

Back to Soil Nitrogen and Other Processes
Back to S04 Soil Fertility & Plant Nutrition

Back to The ASA-CSSA-SSSA International Annual Meetings (November 6-10, 2005)