Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 12, 2000
Publication Date: N/A
Interpretive Summary: Disposal of saline drainage water is a significant problem for irrigated agriculture. The first step in solving the problem is to reduce the volume of drainage water by improving irrigation efficiency. This can be accomplished by improving management of existing irrigation systems, changing to a more efficient irrigation system, or using some of the shallow ground water to meet the crop water requirements. The operation o a subsurface drip irrigation system was compared to a furrow irrigation system for three years in the presence of shallow saline ground water. The results of the project demonstrated that both hard hose and drip tape can be used in a subsurface drip system on a field scale. The yields of cotton and tomato were higher with the subusrface drip system than with the furrow irrigation system. The crops grown with the subsurface drip system used more shallow ground water than those grown with furrow irrigation. Soil salinity management was not a problem with either system.
Technical Abstract: A three year project compared the operation of a subsurface drip irrigation and a furrow irrigation system in the presence of shallow saline ground water. We evaluated 5 types of drip irrigation tubing installed at a depth 0.4 m with lateral spacing of 1.6 and 2 m on 2.4 ha plots of both cotton and tomato. Approximately 40% of the cotton water requirement and 10% of the tomato water requirement was obtained from shallow (<2m) saline (5 dS/m) ground water. Yields of the drip irrigated cotton improved during the 3 year study while the furrow irrigated cotton remained constant. Tomato yields were greater under drip than under furrow in both years tomatoes were grown. Salt accumulation in the soil profile was managed through rainfall and pre-plant irrigation. Both drip tape and hard host drip tubing are suitable for use in our subsurface drip system. Maximum shallow ground water use for cotton was obtained when the crop was irrigated only after a leaf water potential (LWP) of - 1.4 Mpa was reached Drip irrigation was controlled automatically with maximum application frequency of twice daily. Furrow irrigation was controlled by the calendar.