Lysimeter experiments were carried out at Sakha Agric. Res. Station during
the two growing seasons of 1999/2000 and 2000/2001 in three successive crops to
study the effect of different water sources and water regime on the productivity of
maize, sugar beet and cotton crops, some soil chemical properties and water
relations under surface and suo surface irrigation. The main results can be
summarized as follows: 1- There were significant affects of water sources, methods of irrigation and water
applied levels on yield and yield components of the three crops. Irrigation with
secondary treated sewage water produced the highest yield and its components
under surface irrigation method. The irrigation at 50% depletion of available soil
moisture (b) gave the highest yield and yield components of the three crops.
While the lowest yield was obtained with irrigation at 80% depletion of available
soil moisture by well water. 2- The contents of macro and micro nutrients and heavy metals in maize grains,
sugar beet roots and cotton seeds were increased with secondary treated
sewage water followed by drainage water. While the lowest content was
achieved by fresh water. The concentration of elements in maize grains was
higher than sugar beet roots and cotton seeds by about 16 and 25%,
respectively. The surface irrigation increased the elemental contents of maize,
sugar beet and cotton by about 20, 10 and 5%, respectively over that with sub
surface irrigation. 3- Soil salinity (ECe) and alkalinity (SARe) were increased as a result of irrigation
by well water under subsurface irrigation and irrigation at 80% depletion of
available soil moisture. While the lowest values of ECe and SARe were obtained
with irrigation at 35% depletion of available soil moisture by fresh water under
surface irrigation. 4- Soil elemental content was increased with low quality water, this increase was
pronounced with irrigation at 35% depletion of available soil moisture by sewage
water and drainage water under surface irrigation.        5-     The highest amount of irrigation water applied and water consumptive use
(WCU) were obtained with irrigation at 35% depletion of available soil moisture
under sub surface irrigation method. While the irrigation at 80% depletion of
available soil moisture and surface irrigation method recorded the highest values
of crop water use efficiency (CWUE).