Soil compaction is one of the most important factors responsible for soil physical degradation. It alters the structure of cultivated soil and thus changes a number of key soil properties for crop production and the environment. Soil mechanical resistance can be used as indicator of soil compaction. For on-the-go mapping of spatial variability in soil compaction, single- and multiple-tip horizontal sensors have been developed and used to measure the soil mechanical resistance. However, it has been reported that the measured soil resistance in different soil layers depends on failure mode induced by the shank of the sensor. It was hypothesized that the differences in acoustic signals detected by microphones inserted in the tips of a multiple-tip horizontal penetrometer could be used to differentiate the failure modes. In this research, an acoustic multiple-tip horizontal penetrometer was developed, with three 30° prismatic tips working at depths of 10, 20 and 30 cm. The prismatic tips were attached horizontally to S-shape load cells housed inside a box behind the sensor vertical shank. The tips working at 10 and 30 cm deep were also fitted with the microphones. With this arrangement, as the combined sensor is being pulled through the soil, it measures soil mechanical resistance at three depths and it senses sound emitted by the soil failure at two depths. The sensor was tested in a field with silty clay loam soil at four water contents (WCs) of 0.5PL (plastic limit), 0.7PL, 0.9PL and 1.1PL. Cone index (CI) values were obtained with 2 cm depth increments and 1 m horizontal intervals along each transect for comparison using a standard cone penetrometer. Results showed that the soil WC had a significant effect on average horizontal resistance index (HRI) at both depths of 20 and 30 cm. With an decrease in mc, both HRI and CI values were significantly increased. The critical depth of the shank, in which the soil failure transition from brittle to compressive occurs, significantly increased while the soil WC decreased. When the prismatic tips were operated below the critical depth of the sensor (tips at depths of 20 and 30 WC), there was a significant relationship between HRI and CI, whereas for shallower depth the relation was not significant. This was due to change in failure mode from brittle to compressive mode below the critical depth. Therefore, the correlation between measurements obtained with both vertically and horizontally operated penetrometers would be significant as long as both produced the same soil failure mode. Result of recorded sounds at depths of 10 and 30 cm showed that power spectral density acoustic signals at both depth of 10cm (brittle failure mode) and 30cm depth (compressive failure mode) soil were significantly different. A capacitance sensor was designed and developed soil water content. The measurement principle depends on the electrice field of fringe-capacitance. The sensor was tested in 3 soil textures (sandy, sandy loam and clay loam).The estatic calibration results indicated that there was a quadratic relationship with high coefficient determination between the soil water content and sensor's output. Soil's texture affected the sensor's output. There was the measured WC were texture-specific. The result showed the developed sensor can detect soil failure mode in addition to measure the soil horizontal resistance index. Keywords : Precision farming; soil compaction; brittle failure; plastic failure;Capacitance sensor; measuring soil water content.