SUBSURFACE DRIP IRRIGATION EMITTER SPACING EFFECTS ON SOIL WATER REDISTRIBUTION, CORN YIELD, AND WATER PRODUCTIVITY

Emitter spacings of 0.3 to 0.6 in are commonly used for subsurface drip irrigation (SDI) of corn on the deep,silt loam soils of the U.S. Great Plains. Subsurface drip irrigation emitter spacings of 0.3, 0.6, 0.9 and 1.2 in were examined for the resulting differences in soil water redistribution, corn grain yield, yield components, seasonal water use, and water productivity in a 4-year field study (2005 through 2008) at the Kansas State University Northwest Research-Extension Center: Colby, Kansas. The results indicate that there is increased preferential water movement along the dripline (parallel) as compared to perpendicular to the dripline and that this phenomenon partially compensates for wider emitter spacings in terms of soil water redistribution. Corn yield and water productivity (WP) Were not significantly affected by the emitter spacing with application of a full irrigation regime.