Battery-Operated Color Video Camera for Root Observations in Mini-Rhizotrons1
- D. R. Upchurch and
- J. T. Ritchie2
A previously described system (Upchurch and Ritchie, 1983) for observing roots in situ has been modified to include a color video camera. The previous system used a black and white video camera and borescope for observations and included several bulky components which caused damage to the crop and made maneuvering difficult. To allow differentiation of new and old roots and improve field performance and picture quality, a color camera and battery-operated components were added. The new system involved lowering a small video camera and optics system into 51 mm inside diameter (ID) clear, acrylic tubes, which are buried in the soil, and observing the roots intersecting the tubes on a video monitor. All components were battery operated and mounted on a backpack facilitating use of the system in the field. The new system requires approximately 0.3 person h per scan of a 2.4 m mini-rhizotron. Use of a color camera allowed easier identification of smaller diameter roots and provided an indication of relative root age. As noted in other reports, the technique underestimates root length density near the soil surface. The overall average coefficient of variation was 100%, but when the near surface zone and zone near the rooting front are not considered this was reduced to 30%. Statistically significant differences in rooting between irrigated and water-stressed maize (Zea mays L.) could be shown for several depths and dates.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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