Determination of the Physical and Economic Water Productivity for Grain and Forage Corn under Modern and Traditional Irrigation Systems in Hamadan Province

The importance of water as the rarest input to agriculture has led to more attention to increasing the irrigation productivity in recent years. In this study, the compasrison of water productivity in traditional and modern irrigation systems for grain and forage corn in Hamadan province is conducted using three indices of physical and economic productivity of water including CPD, BPD, and NBPD. Firstly, appropriate operators were selected by random sampling and then the necessary data were collected through interviews and completion of the questionnaire. The average physical productivity of water under traditional and modern irrigation systems for grain corn was 0.82 and 1.08 kg/m3 of water, respectively, and for forage corn was 5.11 and 6.67 kg/m3 of water, respectively. The average economical water productivity under traditional and modern irrigation systems for grain corn was 2,849 and 3,665 rial/m3 of water, respectively, and for forage corn was 7,678 and 10,068 rial/m3 of water, respectively. Under modern irrigation systems, the highest amounts of physical and economic productivity of water for grain corn belonged to Asadabad and Nahavand, respectively. For forage corn, the highest amount of physical water productivity was for Nahavand and Tuyserkan and the highest economic water productivity was for Bahar and Nahavand. Based on the results, it can be claimed that traditional irrigation systems should be replaced by modern irrigation systems for grain and forage corn. Also, the cultivation of forage corn should be removed from the cultivation pattern in the Bahar region. These results, in addition to reducing the agricultural water consumption, entail economic benefits for farmers.