Submitted to: Meeting Abstract
Publication Type: Other
Publication Acceptance Date: 4/15/2015
Publication Date: 4/15/2015
Citation: Evett, S.R. 2015. How to save water by choice of irrigation application method. Meeting Abstract. CREET Beat interview on KGNC Radio.
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 5 to 4 inches of water that was lost to evaporation 2013 and 2014, respectively. In the relatively dry 2013 season, SDI increased corn yields by 35 bu/acre (20%) compared with MESA irrigation. At a low-end water pumping cost of $5 per acre-inch, this amounted to $25 per acre less cost to produce corn. And, corn yield was 33 bushels per acre larger for SDI. At the low end of corn prices, $3.65 per bushel, this amounts to $120 per acre more income with SDI. The net gain in income using SDI was $145 per acre. The positive results with SDI also apply to irrigation of turf and landscape plants in our towns and cities across the Panhandle. The Southern High Plains is a part of the United States that suffers from very nearly the greatest potential evaporation demand anywhere in the continental USA. This is due to the strong, dry and hot prevailing southwest winds in the spring (especially) and in the summer. Those winds first cross the Sonoran and Chihuahuan deserts before getting here. At Bushland the long term annual measured free water surface evaporation is 72 inches. Sprinkling lawns and landscaping is throwing water away. Drip irrigation is a great alternative for irrigating landscape plants, and it is well within reach of the average homeowner with average skills to install using products from the local lumber and hardware store. SDI irrigation of turf grass results in very nice turf while using much less water than is used if sprinkler irrigation is used.