Soil & tillage research vol:86 issue:2 pages:218-229
On-line measurement of soil compaction is needed for site specific tillage management. The soil bulk density (rho) indicating soil compaction was measured on-line by means of a developed compaction sensor system that comprised several sensors for on-line measurement of the draught (D) of a soil cutting tool (subsoiler), the soil cutting depth (d) and the soil moisture content (w). The subsoiler D was measured with a single shear beam load cell, whereas d was measured with a wheel gauge that consisted of a swinging arm metal wheel and a linear variable differential transducer (LVDT). The soil w was measured with a near infrared fibre-type spectrophotometer sensor. These on-line three measured parameters were used to calculate p, by utilising a hybrid numerical-statistical mathematical model developed in a previous study. Punctual kriging was performed using the variogram estimation and spatial prediction with error (VESPER) 1.6 software to develop the field maps of rho, soil w, subsoiler d and D, based on 10 m x 10 m grid. To verify the on-line measured rho map, this map was compared with the map measured by the conventional core sampling method.