2019 ASHS Annual Conference
Using Aquarium Test Strips and a Nix Pro Color Sensor to Precisely Determine Nitrate Runoff Concentrations from Containerized Plants
Using Aquarium Test Strips and a Nix Pro Color Sensor to Precisely Determine Nitrate Runoff Concentrations from Containerized Plants
Wednesday, July 24, 2019
Cohiba 5-11 (Tropicana Las Vegas)
Nitrate runoff can be a serious problem for commercial nurseries, as nitrates lost from containerized crops during irrigation can contaminate ground water systems. Nitrates and other nutrients found in runoff water are also essentially wasted fertilizer and wasted money. There are numerous methods for measuring nitrate concentrations in water, although some of them are expensive, complicated, time-consuming and require the use of various isotonic reagents or toxic reagents that contain Cadmium. Aquarium test strips can be used to measure nitrate concentrations in runoff water as they are inexpensive, easy to use, and give a quick reading in just one minute. However, they can be difficult to interpret, since the color that develops on the strip has to be matched with color keys provided by the strip manufacturer. These color keys are not very exact; they only provide a few colors that match up with predetermined reference concentrations such as 10ppm, 25ppm, 50ppm nitrate. The user has to visually guess if the strip color matches one of the reference colors or if it is intermediate between two of them; that is not very precise. The precision of the aquarium test strips can be improved considerably if a Nix Pro Color Sensor is incorporated into the test procedure. The Nix Pro can determine the exact color (RGB, CIELAB, CMYK) not only for the printed color reference keys, but also for each test strip as it develops color after being dipped into the runoff solution. Additional nitrate stock solutions can be prepared for intermediate nitrate concentration values between those provided by the strip manufacturers (e.g. 8ppm, 12.5ppm, 14ppm, 17ppm nitrate, etc.) and the colors that develop on the test strips for those intermediate nitrate solutions can also be determined exactly. The colors that develop on the test strips from the runoff solutions can then be compared to the colors that developed from the various known nitrate concentration solutions. This technique allows for a simple, but much more precise determination of nitrate concentrations in the runoff water from containerized plants.