Effects of Controlled Drainage on Soil Salinity, Irrigation Management and Sugarcane Yield at Imam Khomeini Plantation

The Imam Khomeini sugarcane agro-industry plantation is one of ten sugarcane plantations in Khuzestan province. Today, salinity has been lowered to well below crop salt tolerance level, but deep subsurface drainage and over-irrigation has occurred and deposits a significant amount of drainage water back into Dez River each year. This study investigated the impact of controlled drainage on the reduction of irrigation water, soil salinity, drainage volume, salt load and sugarcane yield for two fields. One field had free drainage (FD) and the other had controlled drainage (CD). In the CD system, water depth control level was 90 cm below the soil surface. Results showed that the amount of irrigation water for CD decreased by 27% and reduced total drainage outflow by 55%. During this time, the CD the salt load decreased about 24 ton/ha and crop yield increased 8.7%. Controlled drainage significantly reduced the amount of irrigation, drainage volume and salt load over the free drainage system. This method is a feasible solution to decreasing river pollution and has a positive hydrological and environmental impact.