A system for on-line measurement of key soil properties

This paper reports on on-line measurement of total nitrogen (TN), organic carbon (OC), moisture content (MC) and bulk density (BD) which was carried out in three European farms. The measurement system consists of a multiple sensor platform, which includes a mobile, fibre-type, visible and near infrared (vis-NIR) spectrophotometer, a draught (D) and a depth (d) sensor. The prediction models developed were tested in three fields in Denmark, Czech Republic and UK. Results revealed that the measurement accuracy was very good for TN (RPD = 2.33 - 2.38), very good/excellent for OC (RPD = 2.31 - 2.52) and excellent for MC (RPD = 3.16 - 3.25). A reasonably good correlation between the measured and on-line predicted BD (R2 = 0.56 – 0.73) was obtained. The online measured maps were similar to those developed with traditional laboratory method of soil analysis.