الفهرس 
chapter 1Only 14 pages are availabe for public view
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Abstract
Water scarcity is one of the greatest problems facing countries in arid and
semiarid region. This problem force.-; them to use marginal water of low quality and
quantity for irrigation. These kinds of waters have many associated problems. These
problems appear during collection, storage and use of these waters. The main problems
may be: soil erosion as a result of rainfall action, siltation a! the bottom of reservoirs
constructed to harvest water, infiltration of saline water and pollution bringing the risk to
the soil and the groundwater. The present study aimed to investigate these problems. In
order to achieve this aim. observation techniques were monitored to measure the different
important variables (water content, ;soil salinity and soil water salinity). This investigation
was partly done in laboratory experiments. These experiments aimed at comparing
devices for measuring salinity (Time Domain Reflectometry TDR and Sigma Probe SP).
Soil solution electrical conductivity (o;..) from time domain reflectometry {TDR) and
Sigma Probe (Sp) meaSurement techniques was compared in the laboratory experiment
using seven different soil types over a wide range of water contents {0). We concluded
that the differences between the techniques could probably be attributed to the different
sampling volume and !he different measuring frequency. Using the SP with a default soil
speCific parameter Ko value or 4.1, gave a ow that W\IS +- 20% of the true (Ji” when cr,..>l
dS m-1 in all examined soil types. Tire TDR measurements of cr,., using a conventional aw•
cr._~O model were more accurate in all soil types.