Laboratory based near infrared spectroscopy (NIRS) has demonstrated good predictive capability for many important soil constituents. Less is known about the feasibility of performing the spectroscopic measurements in a field setting. This paper presents some results of an initial field test of a mobilized in-situ NIRS device. The results demonstrate good pass-to-pass repeatability and meaningful qualitative images. Locally weighted principal component regression was used to develop calibration models relating the reflectance data to levels of soil organic carbon, nitrogen, moisture and pH. The calibrations were used to create constituent maps for a field in central Iowa and compared to images derived from intensive sampling and laboratory analysis.
