A Comparison of Three Light Sources for VNIR Analysis of Soil Samples.

Approximately 3000 crushed, sieved, <2mm soil samples from the USDA/NRCS Soil Survey Laboratory archive were scanned with contact probe, muglight, and turntable VNIR light sources. Predictive models were developed for multiple soil properties, including total carbon, carbonate, gypsum, and total clay. While little difference was noted in the accuracy of the models in most cases, the muglight tended to have the least variability between replicates of samples, and the turntable had the greatest variability between replicates.