|Reeves Iii, James|
Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 7/29/1999
Publication Date: N/A
Technical Abstract: The objective was to investigate the potential of near-infrared reflectance spectroscopy for soil evaluation under varying conditions of soil diversity using 3 sample sets: 1. 179 samples collected at 5 depths from 2 sites containing plow tilled and no-till plots, but of limited soil diver-sity; 2. 64 samples randomly collected from a 20 ha agricultural field which comprised a substantial part of a toposequence within a small watershed; 3. 547 samples collected in a grid pattern from the soil surface (0 - 10 cm) and sub-surface (10 - 30 cm) at 274 locations (1 lost) from the 20 ha field. Samples were scanned from 400 or 1100 to 2498 nm using a rotating cup and scanning monochromator. Results for the set of 179 samples (ground) were excellent for total C and N with calibration R2 of 0.964 and 0.962, respectively. Similar results were obtained for C for the more diverse set of 64 samples when ground, but results were considerably less satisfactory on un-ground samples. Results on the set of 547 samples also indicated that sample grind may be very important in developing accurate calibrations. In conclusion, soil diversity may be less of a problem than grind for NIR calibrations.