Submitted to: Proceedings of the Central Plains Irrigation Conference
Publication Type: Proceedings
Publication Acceptance Date: 2/17/2015
Publication Date: 2/17/2015
Citation: Evett, S.R., Brauer, D.K., Colaizzi, P.D., Oshaughnessy, S.A. 2015. Corn and sorghum performance affected by irrigation application method:SDI versus mid-elevation spray irrigation. Proceedings of the Central Plains Irrigation Conference.
Interpretive Summary: In the semi-arid Southern High Plains, irrigation before planting and after planting is often required to prepare the soil for planting and obtain good seed germination and early plant growth. During this period until at least 25 days after planting, there is little plant cover, and most water losses are from evaporation from the soil surface. Subsurface drip irrigation (SDI)avoids wetting the soil surface, unlike sprinkler irrigation, but the amount of water that can be saved due to reduced evaporation is unknown for this region. Scientists at the USDA-ARS Conservation & Production Research Laboratory measured the evaporative loss from spray sprinkler and SDI application methods while growing corn and sorghum crops. They found that between 2.2 and 2.5 inches of water could be saved using SDI in the period from first pre-plant irrigation to 25 days after planting. The reduced pumping costs are conservatively estimated at $12 to $24 million dollars if SDI were applied on all irrigated acres in the Texas Panhandle. The scientists also found that corn yields were boosted by 20% (35 bushels per acre) using SDI, while season long water use was reduced by 3.6 inches.
Technical Abstract: It is known that irrigation application method can impact crop water use and water use efficiency, but the mechanisms involved are incompletely understood, particularly in terms of the water and energy balances during the growing season from pre-irrigation through planting, early growth and yield development stages. Grain corn (Zea mays L.) and sorghum (Sorghum bicolor L. Moench) were grown on four large weighing lysimeters at Bushland, Texas in 2013 (corn) and 2014 (sorghum). Two of the lysimeters and surrounding fields were irrigated by subsurface drip irrigation (SDI) and the other two were irrigated by mid elevation spray application (MESA). Crop evapotranspiration (ETc) was measured using the weighing lysimeters and soil water content was measured using the neutron probe and electromagnetic sensors. Periodic measurements of plant height, width, leaf area index and biomass were made, and final biomass and yield were measured. Micrometeorological measurements included incoming and outgoing short and long wave radiation, soil heat flux, precipitation, air temperature and humidity and wind speed. Irrigation amounts were metered. Compared with MESA irrigation, using SDI saved from 2.5 to 2.2 inches of water that was lost to evaporation early in the season (pre-plant to 25 days after planting) in 2013 and 2014, respectively. While sorghum, particularly short season sorghum, is not a crop ordinarily considered for SDI, it was grown successfully using SDI with yields averaging 120 bu/acre, comparable to others reported for short season sorghum at Bushland. In the relatively dry 2013 season, SDI increased corn yields by 35 bu/acre (20%) compared with MESA irrigation, while reducing overall corn water use by 3.6 inches.