Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/13/2017
Publication Date: 6/15/2017
Citation: Evett, S.R., Brauer, D.K., Colaizzi, P.D., Marek, G.W., Oshaughnessy, S.A., Moorhead, J.E. 2017. SDI increases water use efficiency of grain crops in the Southern High Plains. 2017 UCOWR/NIWR Annual Conference, Fort Collins, CO, June 13-15, 2007.
Technical Abstract: In the semi-arid Southern High Plains, nearly all irrigation water is derived from the declining High Plains (Ogallala) aquifer. As well capacities likewise decline, one tactic for continued irrigation is to install subsurface drip irrigation (SDI) systems with zones sized to accommodate the limited flow. Other reasons for adopting SDI include the documented increases in cotton yield and water use efficiency (WUE) with these systems compared with sprinkler irrigation, the much reduced evaporative loss compared with sprinkler systems, and the promise of increased WUE with other crops. Improvements in grain crop WUE with SDI have not been sufficiently documented, nor have the underlying mechanisms leading to increased yield and WUE been well understood. We compared yield, water use (evapotranspiration, ET) and WUE for sorghum and corn crops grown using SDI and a linear-move sprinkler system equipped for mid elevation spray application (MESA). ET was determined using four large precision weighing lysimeters and a network of eight neutron probe access tubes in the field around each lysimeter. Each lysimeter was in the center of a square 4.4-ha (11-acre) field. Grain corn (Zea mays L.) and sorghum (Sorghum bicolor L. Moench) were planted in 2013 and 2014, respectively. In those two years, using SDI saved 85 and 53 mm (3.3 and 2.1 in) of water that was lost to evaporation early in the season (pre-plant to 25 days after planting), compared with MESA irrigation. In the relatively dry 2013 season, SDI reduced overall corn water use by 147 mm (5.79 in) while increasing yields by 1.88 Mg/ha (1,680 lb/acre, 20%) and WUE by 0.64 kg/m**-3 (1740 pounds/acre-ft-1, 61%) compared with MESA full irrigation. Short season sorghum, although not a crop ordinarily considered for SDI, was grown successfully using SDI with yields averaging 6.48 Mg/ha (5,780 lb/acre).