Abstract: A soil moisture sensing device for sensing moisture levels in a particular soil area. The device has a porous body with at least two zones, a first one of the zones having pore sizes that approximate a range of pores in typical soils, a second one of the zones having pores arranged to be small enough to remain hydrated at higher matric tensions. The first and second zones contain respective electrodes, each being paired with an electrode common to both zones. As the matric tension of the soil solution increases, the pores within the first zone dehydrate causing increased resistance between the first electrode and the common electrode while the pores in the second zone remain hydrated, the resistance between the second electrode and the common electrode changing only in response to conductivity of the soil solution in the second zone.

Abstract: The present specification discloses a soil mixture sensing device for sensing moisture levels in a particular soil area under surveillance, the device having a porous body (11) which in use is placed in the soil area under surveillance, the body (11) having at least two zones, a first one of said zones (11) having pore sizes that approximate a range of pores in typical soils, a second one of the zones (14) having pores arranged to be small enough to remain hydrated at matric tensions of the soil solution significantly above those which cause the first zone (11) to dehydrate, the first zone (11) containing a first electrode (12) and the second zone (14) containing a second electrode (16), each of which are paired with an electrode (17) common to both said zones (11) and (14) whereby, as the matric tension of the soil solution in the soil in the surveillance area increases, the pores within the first zone (11) progressively dehydrate causing electrical resistance between the first electrode and the common elect