The meter measures the ratio of radiation transmittance from two wavelengths (red, strongly absorbed by chlorophyll, and near infrared, not absorbed by chlorophyll), making measurements non-destructive and nearly instantaneous (measurement time is less than 3 seconds). This facilitates rapid measurement of multiple leaves and monitoring of the same leaves over time.
Storage Capacity and Geo-referencing
Memory allocated to data storage allows for 160,000 logged measurements. A mini USB port allows for direct connection to a computer to download data. Chlorophyll meter comes with a standard mini USB to USB cable for data download. An RS-232 port is available for external GPS connection, allowing field data to be geo-referenced. Storage capacity of geo-referenced data is 94,000 measurements.
Specific crop species settings in the meter include rice, wheat, soybean, barley, pepper, tomato, pea, kahlrabi, Walderman's Green lettuce, Buttercrunch lettuce, corn, sorghum, Quaking Aspen, European Birch, Paper Birch, Crimson King Maple, Norway Maple, Japanese Maple, Boxelder, Crab Apple, Purple Leaf Sand Cherry, lilac, Forsythia, grapevine, cannabis, coffee, spinach, strawberry, and a general setting used for all other species.