The study aimed to measure the total influence of various factors (cultivated
area, yield, price) of Economic Importance. Which affect the Productivity of wheat,
summer maize and summer rice, and measure influence of the interaction among
these factors that affect changeablity of the economic importance of each crop. And
determine the responsibility about the gained changes in other to develop some
economic indicatory that would help planners and price decision makes to achieve
their tasks successfully. Methodology of the study was based on using some index numbers in to partial index number for each factor. Also both investigation methods of the separated change and the shared change were followed. Through studying the producing situation: Wheat crops: The study explained that the annual increase rate in cultivated area reached to 5.21 thousand feddan every year, but the annual increase rate for yield reaches to 0.45 Ardab every year, while the annual increase rate for total production reached to 172.04 thousand Ardab every year during the period of the study. Summer Maize crops: The study explained that the annual increase rate in cultivated area reached to 0.36 thousand feddan every year, but the annual increase rate for yield reached to 0.62 Ardab every year, while the annual increase rate for total production reached to 0.53 thousand Ardab every year during the period of the study. Summer Rice crop: The study explanlned that the annual increase rate in cultivated area
reached to 15.69 thousand for yield reached to 0.134 tons every year, while the
annual increase rate for total production reached to 95.26 thousand tans every year
during the period of the study. The main findings revealed that there were some factors that strengthen the economic importance of the mentioned crops, while there were another factors the weahen this importance, Also the price policy proved to be the main factor in this concern, therefore reasonable and continuous price changes were recommended in this study in order to encourage farmers to increase the required crops.