IRRIGATION of forests with sewage water for fuel and timber production in
Egypt is an approach which helps to overcome health hazards associated with
sewage farming. Hopefully, sewage water will help in the expansion of the irrigated
agriculture or save the fresh water for other sectors. This study was carried out to
investigate the impact of irrigation with treated sewage water on the properties and
nutrients status of soils in Luxor Governorate. samples of sewage water, ground
water and Nile water as well as samples of soil irrigated with these water sources
were collected and analyzed.
The results showed that sewage water and groundwater are considered
moderately saline with an ECw of 0.88 and 1.20 dS/m, respectively, while the Nile
water is slightly saline (ECw 0.27 dS/m). With respect of their SAR, RSC and Cl
values, all investigated water sources are of a high quality and can be used in the
irrigation without limitations. Moreover, sewage water contained higher amount of
organic matter, N, P and K compared to groundwater and Nile water.
On the other hand, most of the soils that were irrigated with sewage water were
of low levels of salinity (ECe < 4dS/m) and sodocity (SARe <13), indicating no
threat to soil quality. Use of sewage water in irrigation also improved the chemical
properties and fertility status of the soils. It increased OM, N, K and P levels in the
soils while pH and CaCO3 values decreased. The irrigation system showed effects
of treated sewage water on the soil properties. The soils irrigated with sewage water
under the surface irrigation system had higher values of OM, ECe, total nitrogen
and available phosphorus but lower SARe and available K levels than those under
the drip irrigation systems. Moreover, prolonged irrigated (15 years) with sewage
water had a higher values of saturation percentage, organic matter, total nitrogen,
available phosphorus, and available K but the lower ones of pH, SARe and calcium
carbonate than those under the short term (4 years) use of sewage water.