Despite the importance of sunflower crop as oil crop and a source for nutritional protein, it still cultured in narrow limit all over the country due to the difficulties that facing its culturing which are represented by heavy and cost serving processes required to produce this crop. So, this study aimed to estimate total production cost function for this crop and calculate the percent of achieved size economics in Wasit governorate for the agricultural season 2006.
The estimate results indicated that variable cost had the highest percentage of total crop cost for the studied sample as it represented 90% of the total cost. That was because the items of variable costs included most sunflower production costs since maintenance cost took the first tank (22.1%) followed by fertilizers (19.43%) , then machines and instruments repairing (14.6%) followed by the other items.
The first costs represented only 10% of total costs due to the absence of most of their items.
The results of this study demonstrated that the typical production size of the crop is 126.06 tons. The country estate possession size of the studied sample ranged from 10 to 300 hectare with none of size classes has the typical production size which is determined by this study. The cubic function was used as it has high significance indicators.