Experiments were conducted at EI·Bramoon Exp. Farm, Hort. Res. Inst., during
2001 and 2002 summer season. In order to study the effect of NaCI salinities (0 • .4000
and 6000 ppm) and the applied ameliorative ions, phosphate (phosphoric acid form,
0.35 mill), nitrate (nitric acid form, 0.35 mill) and Citrate (citric acid form, 5 gil) In
irrigation waler and their Interaction on the ionic, physiological and agronomlcal
performances of Baladi cowpea. Each three weekly successive salt treatments were
followed by one ameliorative ion treatment up 10 nine and three applications
respectively during the season. Results could be summarized as follows:· Effects cJ salinity: As the intensity of NaCI salt stress Increased, plant height, dry
matter I plant (g), number of flowers and pods I plant. pods and seeds yield I
plant (g) were significantly decreased in the two seasons. The whole plant dry
weight decreased by 20.7 and 31.0% (mean of two seasons relative to control) at
moderate and high (4000 and 8000 ppm NaCI), respectively. Also, pods and
seeds yield were decreased by 24.6 and 25.6% and 46.8 and 47.0%,
respectively. Effects of the ameliorative ions: Applying phOsphate followed by nitrate and
citrate were significantly improved growth and yield as they greatly reduced the
accumulation of salt ions and improved useful nutrients. protein and
carbohydrates content. Also, Increased the whole plant dry weight by 51.9, 41.4
and 25.7%. pods and seeds yield by 46.5 and 47.7%; 31.0 and 32.4% and 22.3
and 11.4%, respectively relative to the control. Effect of interaction: The presence of phosphate followed by nitrate and citrate
ions In growth substrate was greatly reduced the adverse effects 01 moderate and
to some extent of higher salinity, Phosphate was the most effective one. At
moderate salinity, total dry weight reduced by 30.1%. pods and seeds yield by
30,7 and 32.6%, after phosphate application those were fully restored to the
normal values of control or above, they were increased by 10.0, 4.3 and 4.9%.
respectively. At higher salinity, those were reduced by 43,0, 54.2 and 52.0%,
respectively, phosphate alleviated the declines to be only 3.9. 25.0 and 26.5%.
respectively.         4,     A positive correlation between pod and seed yields vs. total dry weight, total
carbohydrates, crude protein, N, P, K. Ca, KINa and CalNa values was observed.
On contrary, negative correlation was found with Na and CI content. Correlation
values confirmed the essentiality of KINa, CalNa, protein. Na and CI values and
contents as Indicators for salt adaptation.           5,    Baladi cowpea considered as relatively less salt sensitive (moderate salinity)and
moderately sensitive (higher salinity), they maintained no extreme physiological
disturbances parallel with no agronomlcal extreme alterations as NaCllevels was
double folded. It could be concluded, with adding phosphate (phosphoric acid, 0.35 mIlL)
through three applications in irrigation water during the grOWing season of
cowpea to obtain normal yield at moderate (4000 ppm NaCI) and less reduced
yield at higher (8000 ppm NaCI) salinities. Also. nitric and citric were of beneficial
effects.