الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
The aim of this investigation was to study the nutrient
supplying power of different layers of calcareous soils as influenced
by quality of irrigation water and its effect on yield and chemical
composition of some forage plants variable in their nature specially
root system.
To achieve the purpose of this study, representative soil
samples were taken from two profiles representing the calcareous
soils of Noubaria Agricultural Station Farm and Abou-Massoud
village at profile depths of 0-30,30-60 and 60-90 em. Seven Kgs.
Portions of each soil layer were packed in 24 pots divided into two
groups. The first group was planted with sudangrass ( Sorghum
vulgare ) and the other one was planted with alfalfa ( Medicogo
sativa) . Each group was then subdivided into four sets (3 pots set
-1) to be irrigated with tap water or saline water having a
concentration of 1000, 2000 or 4000 ppm as NaC!. The soil
moisture content was maintained at the field capacity throughout
the whole period of the experiment. Four cuts of each crop were
taken after 50, 100, 150 and 200 days from planting and analyzed
for N, P and K. In addition to the descriptive physical and chemical
analyses of each soil layer I a soil sample from each pot was taken
just after removing the plants and chemically analyzed to follow up
the changes that might have occurred in some of the soils
properties as result of putting them under cultivation and irrigation
with saline waters.
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7- Although all layers were of relatively low cation exchange
capacity, yet the middle layers showed slightly higher values than
the other ones.
8- The highest contents of the nutritive elements were found in the
surface layers whereas the lowest contents were achieved in the
deepest ones.
B) Changes in soil chemical properties due to cultivation and
irrigation with saline water:
1- Salinity of all layers of both the investigated soils increased to
different extents, dependent on quantity of water retained and its
concentration of soluble salts .
2- Soil content of Na , CI and S04 increased and the increase was
more noticeable by increasing salinity of the irrigation water.
3- Values of sodium adsorption ratio (SAR) increased . The
increase was more obvious in the soil layers planted with alfalfa
than in the ones cultivated with sudangrass.
4- Values of soil pH increased slightly and the increase was more
obvious by increasing salinity of the irrigation water. 5- Exchangeable sodium percentages (ESPs) increased with
increasing salinity of the irrigation water.