The 2008 Joint Meeting of the Society for Range Management and the America Forage and Grassland Council. |
Wednesday, January 30, 2008 - 9:00 AM
Alfalfa Yield and Quality Above Subsurface Drip Irrigation Lines
Keith Harmoney1, Freddie Lamm2, and Sandy Johnson2. (1) Western Kansas Ag. Research Center - Hays, Kansas State University, 1232 240th Ave., Hays, KS 67601, (2) Northwest Research and Extension Center, Kansas State University, 105 Experimental Road, Colby, KS 67701
Alfalfa is an increasingly important crop in western Kansas to supply a growing dairy industry with high quality hay. Subsurface drip irrigation systems under alfalfa are viewed as an alternative to pivot irrigation systems in this region to increase efficiency of water use and to remedy issues with declining groundwater supplies. Alfalfa production and quality was monitored at 0, 15, and 30-inch distances (DIST) from a subsurface drip line where water was released into the soil at three levels of irrigation, namely 100%, 85%, and 70% of evapotranspiration (ET) rates. Five harvests (HARV) were made in each of two years (YR), 2005 and 2006, but no HARVxDISTxET interaction was detected for quality traits. However, a YRxDISTxET interaction developed for both crude protein (CP) and in situ dry matter disappearance (ISDMD). Both CP and ISDMD were greater at lower ET irrigation rates and at greater distances from the drip line, except in 2005 when the 100% ET treatment 0 inches from the drip line had similar CP and ISDMD values as the 85% and 70% ET treatments at 0 inches from the drip line. Total digestible dry matter yield (DDMY) was not different for any treatment, so yield reductions from irrigation treatments with less water and at further distances from the drip line were offset by greater quality and digestibility.