ekS - Instytut Agrofizyki im. Bohdana DobrzaÅskiego PAN w Lublinie ...
ekS - Instytut Agrofizyki im. Bohdana DobrzaÅskiego PAN w Lublinie ...
ekS - Instytut Agrofizyki im. Bohdana DobrzaÅskiego PAN w Lublinie ...
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Fig. 64.<br />
Approx<strong>im</strong>ate region of influence of the FP probe, defined as a solid beyond of that<br />
changes in water content do not markedly affect readings of water content<br />
12.5. LOM/mpts - Laboratory Operated Meter for recording soil moisture,<br />
matrix potential, temperature and salinity<br />
LOM is a TDR (T<strong>im</strong>e-Domain Reflectometry) technology based, computer<br />
aided instrument, designed to record mass and heat transport data. It is suitable for<br />
controlling long-term laboratory exper<strong>im</strong>ents on soil columns, which require<br />
monitoring of water, heat and salt transport (Fig. 65).<br />
This is achieved by means of periodic recording of instantaneous profiles of<br />
water content, matrix potential (capillary water pressure, "suction force"),<br />
temperature and electrical conductivity in chosen t<strong>im</strong>e intervals. To record water<br />
content, θ, a factory installed conversion equation θ (ε) for mineral soils is<br />
<strong>im</strong>plemented. A calibration function for organic soils as well as a user determined<br />
conversion equation could be also applied. A record of the pulse voltage against<br />
t<strong>im</strong>e, ie the TDR trace, can be stored for independent interpretation. Supplied<br />
software includes executable files and source codes as well. Several LP type<br />
miniprobes of selected type (or of all types) can be inserted through the side wall<br />
of a soil column or a steel sampling cylinder, thus allowing for vertical scanning<br />
of instantaneous profiles of water content, capillary pressure (matrix potential,<br />
suction force), temperature and salinity (bulk electrical conductivity).<br />
This makes it possible to collect a set of corresponding data from transition of<br />
the soil solute (and temperature) front. From this, after processing, one can obtain<br />
a complete set of unsaturated water flow characteristics of the soil such as the<br />
water retention (PF) curve, the unsaturated water conductivity (k-function), the<br />
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