The sensor diu00c9drico to assess tensu00e7o, potential and activity of liquids

摘要

The sensor diu00c9drico to assess tensu00e7o, potential and activity of liquids. In the system of the sensor dihedral, two flat plates are fixed in the dihedral so that the distance between the edge and the meniscus (L) and the distance between plates (a) on the meniscus, are function of the tangent of the dihedral (CL).Thus, for pure water tension ('1') is equal to the potential (T) and given by T = - 2 / [l TG (a)], where a is the surface tension of the water. To measure the tension of water in the soil, the system is coupled to the porous elements, while the edge of the sensor is pressed directly against roots and other plant organs.The potential of water, in contrast, is measured with the edge positioned a few micrometers of the sample and the response occurs after an exchange of a few picoliters of water when the balance condition of temperature and pressure of steam is only approximate.Visually, with calipers, is measured tensions of water between zero and 0.3 MPa, while that with the help of the microscope reading extends to about 3.0 MPa. The activity of water corresponding to the potential of water smaller than - 3.0 MPa, it can also be measured by adding a known amount of solute molecules suitable for water retained in the sensor.