Subsurface drip irrigation for agronomic crops

Drip irrigation offers several advantages over sprinkler irrigation in humid areas, including ease of system start-up each season, ease of automation, lower water pressure, lower water now rate, and improved management of water and nutrients. System cost can be reduced and drip irrigation made more profitable for some agronomic crops through the use of wider spacing and subsurface placement of laterals. Results from three experiments (10 site-years) that evaluated subsurface drip irrigation of agronomic crops are reviewed. Agronomic crops can be effectively and efficiently irrigated in the southeastern Coastal Plain using subsurface drip irrigation systems. In four experiments involving 13 site-years of data, both normal (0.76-1.0 m) and wide (1.5-2.0 m) lateral spacings were used to irrigate corn and cotton; yields were lower for the wide spacing in only one of six years for corn and none of the seven years for cotton. Consequently, it appears that subsurface placement of laterals at wider spacings (1.5-2.0 m) has significant potential for profitable irrigation of agronomic crops in the southeastern Coastal Plain.