A field experimental was conducted in fall 2008 at Heet city of Al Anbar governorate in silty clay soil to study the effect of leaching requirement and plot dimensions on salt distribution and yield of maize crop. In irrigation was used saline mixed water 3 ds.m-1 from salty water well water of 5.83 ds.m-1 from the area has been mixed with Euphrates water of 1.07 ds.m-1. (R.C.B.D) factorial experiment was applied to study two factors the first was Leaching requirements with three level (0%, 15%, 25%) and the second factor was plot dimensions with two level (4×5) and (2×10).The design was used with three replicates.
Results of this experiment showed that :
Using L.R of 15% level caused an increase in grain yield of maize in compared to control where the production was depressed .When increasing L.R level up to 25% the yield was decreased to 10.27 ,11.32 and 10.50 Mg.ha -1 for control, with no addition of L.R there was an increase of an-ions and cations accumulation at soil surface layers and decreased with depth. It were for 35.5 ,37.1 ,35.7 and 32.7 meq.L-1 for depths 0-30 ,30-60, 60-90 and 90-120 cm respectively in comparing with total cautions of the soil before farming for the same depths respectively. They were 12.86 , 14.04 ,11.84 and 8.33 meq .L-1 same result were recorded for the anions, results indicated a decrease in cations and anions concentrations at surface layers and an increase of these ions at the lower layers by using L.R of 15% and 25% level data were 5.81, 7.14, 7.55 and 10.86 meq.L-1 for 15% L.R level for 5 depths 0-30 ,30-60, 60-90 and 90-120 cm respectively, with increasing L.R level to 25% .the total cautions were 4.51, 6.84, 7.25 and 13.5 meq.L-1 for same depths respectively .