Measuring the unsaturated hydraulic conductivity of growing media with a tension disc

摘要: In greenhouse and nursery production, there is an increasing interest in water conservation environmental quality. The use of closed semi-closed subirrigation systems to grow plants potted organic growing media important step this direction. However, the design efficient requires a detailed characterization unsaturated hydraulic conductivity substrates on rewetting. many cases, have extremely high-saturated conductivities also exhibit dual porosity. Given lack suitable technique for measuring these near saturation, as well at saturation pots (the equivalent field conditions production), new situ procedure has been developed. It based analytical solution steady state upward flow assumes single (SEA) or piecewise exponential (PEA) relationship between soil potential. proposed method was tested sand medium. results indicate that curve may be obtained from flux measurements using specifically designed tension disc placed top substrate, estimates rewetting are much more accurate, particularly contents close than those instantaneous profile method. Moreover, easy carry out, only inexpensive sound physical representation process. Results indicated PEA appropriate most SEA can considered special case if one piece required entire range (e.g., sand).