EFFECT Of NITROGEN, SODIUM, CALCIUM AND THEIR INTERACTION ON YIELD AND COMPOSITION OF TOMATO FRUIT.

Sandy culture experiment was conducted at Fac. of Agric., Mansoura University during the two summer   successive seasons of 2010 and 2011 aimed to investigate the effect of N ( 30.0 and 150.0 ppm ) , Na ( 0.0 and 4.0 meq / l) and Ca
( 0.0, 5.0, 10.0 and 20.0 meq / l) in nutrient solution and their interaction   on tomato fruit composition. Combination between the studied factors levels comprise sixteen   treatments which were arranged in a split split block design with 3 replicates .
The obtained results can be summarized in the following :-
Significant increase in  tomato fruit numbers amounted by 19.72 % in the first season and 19.49 for the second one, where the total yield increases were  18.89 and   18.64 for first and second season, respectively . So fruit weight average  significantly varied due to N level increase from 30.0 ppm to 150.0 ppm ( 29.12 and 15.41 % increase in the first and second season, respectively ) .
Sodium application (4.0 meq /l )reduced total yield of tomato fruit by 5.16 % in the first season and a slight increase than that was found in the second one (5.5 % reduction ).
N content of tomato fruit was increased from 2.53 to 3.09 % ( 22.13 % increase ) in the first season and from 2.70 to 3.19 % (18.15 % increase) in the second season  due to N level increase in nutrient solution from 30. to 150.0 ppm. 
  sodium level of 4.0 meq / l in nutrient solution  significantly reduced N, P, and K content of tomato fruits.
              Potassium content of tomato fruits was decresed as nutrient solution Ca increase up to  the highest level used (20.0 meq /l ) in both season. 20.0 meq / l Ca decreased  potassium content of tomato fruit by 5.56 and 4.79 %,  compared with control, in the first and second season, respectively  .
  Neither  statistically  effect nor constant trend was found on total Ca resulting from  increasing the nitrogen level from 30.0 to 150.0 meq /l in both seasons.
 NaCl -Ca took the opposite trend of total calcium, where NaCl -Ca of tomato fruits was increased (5.07 % increase), in the first season and decreased (4.72% decrease) in the second one due to the same increase in N level (from 30.0 to 150.0 meq /l).   
 HAC-Ca, HCl-Ca and Res-Ca showed a constant trend against N level increase in both seasons.   4.0 meq /l treatment significantly increased all Ca forms in tomato fruit  in both seasons, compared with that of no sodium addition .
10.0 meq / l  treatment  achieved the highest values of total  Ca in both season ( 1726.24 and 1768.78 ppm for the first and second season , respectively ).
A concomitant increase in Eth-Ca with increasing Ca level in nutrient solution up to 10.0 meq / l then slightly decreased with 20.0 meq / l treatment in both seasons.
                A strongly increasing trend in NaCl – Ca by increasing Ca level in nutrient solution from 0.0 Ca addition to 5.0 meq /l in nutrient solution (from 883.6 to 1253.48  and from 926.74 to 1222.90 , in the first and second season, respectively  ) .  Lower decreasing rate (from 1396.25 to 1295.65  and from 1330.26 to 1256.98 ppm , in the first and second season, respectively  ) was found regarding to NaCl – Ca form with increasing Ca level from 10.0 to 20.0 meq Ca /l .
  In both seasons Ca oxalate was significantly  increased with increasing Ca level from 0.0 to  10.0 meq /l in nutrient solution, these increases appreciated by 276.49 and 275.33 % in the first and second season , respectively . A significant decrease  in tomato fruit calcium oxalate due to increasing Ca in nutrient solution from 10.0 to 20.0 meq /l ( 26.62% and 25.93% increase in the first and second season respectively ) .