Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/1/2015
Publication Date: N/A
Technical Abstract: Subsurface drip irrigation (SDI) wets the soil at the depth of the drip line and in a volume around each emitter, but the soil wetted often does not include the soil surface. Because of this, the soil surface remains completely or at least partially dry and evaporative losses of irrigation water are much diminished compared with the losses associated with furrow, sprinkler or even low energy precision application (LEPA) of irrigations. Direct and continuous comparative measurements of evaporative losses from SDI and sprinkler irrigation systems are, however, seldom made due to the difficulty of doing so. In 2013 and 2014, direct measurements of ET from SDI irrigated and sprinkler irrigated crops were made using large weighing lysimeters (two with SDI and two with sprinkler) in 4.4-ha fields at Bushland, Texas on the U.S. Southern High Plains. During pre-plant irrigations and until 25 days after planting when plants had emerged and transpiration had become non-negligible, the measurements of ET were essentially measurements of evaporation (E) only. Grain corn (Zea mays L.) and sorghum (Sorghum bicolor L. Moench) were grown in 2013 and 2014, respectively, under well-watered and fertilized conditions conducive to good crop yields. Using SDI saved from 53 to 85 mm of water that was lost to E early in the season (pre-plant to 25 days after planting) in 2013 and 2014, respectively. In 2013, which was relatively dry, SDI reduced overall corn water use by 147 mm while increasing yields by 1.88 Mg/ha (20%) and WUE by 0.64 kg m**-3 (61%) compared with mid-elevation spray sprinkler full irrigation. The sorghum crop was planted after cotton failure in 2014, and so was a short-season sorghum variety. While short-season sorghum is not a crop ordinarily considered for SDI, it was grown successfully using SDI with yields averaging 6.48 Mg/ha, comparable to others reported for short season sorghum at Bushland.