Submitted to: Irrigation and Drainage International Symposium Proceedings
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 1998
Publication Date: N/A
Interpretive Summary: Disposal of saline drainage water is a significant problem facing irrigated agriculture throughout the world. Results of the San Joaquin Drainage Program Study indicated that source control was one of the most effective ways of reducing drainage water volume. Practices included in source control were improved irrigation management, changes in irrigation systems being used, and improvements in irrigation efficiency. This paper describes irrigation management techniques which contribute to source control by implementing new irrigation technologies (subsurface drip irrigation) and improvements in irrigation management. Incorporating cotton water use from shallow ground water into the irrigation schedule and management resulted in less applied water, reduced deep percolation losses, and a reduction in the drainage flows. This technique is applicable in areas with shallow ground water at a depth of less than 2 m and with an electrical conductivity (EC) less than 15 dS/m.
Precisely irrigating a crop in the presence of shallow ground water is difficult because the ground water contribution to the crop water requirement is unknown for most crops. This paper presents the results of irrigating cotton in the presence of shallow ground water using subsurface drip, sprinkler, furrow, and flood irrigation. Yields were generally higher with the pressurized systems compared to the flood and furrow systems. A crop coefficient which accounted for shallow ground water use by cotton was effectively used in reducing the total applied water without reducing yields. Sprinkler irrigation was effective in reducing leaf yellowing of cotton grown in clay soils.