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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Soil and Water Management Research » Research » Publications at this Location » Publication #403282

Research Project: Dryland and Irrigated Crop Management Under Limited Water Availability and Drought

Location: Soil and Water Management Research

Title: Differences in crop coefficients for SDI and sprinkler irrigation

item Marek, Gary
item Evett, Steven - Steve
item Colaizzi, Paul
item O`Shaughnessy, Susan
item Brauer, David
item Ruthardt, Brice
item Copeland, Karen
item HOWELL, SR., TERRY - Retired ARS Employee

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/29/2023
Publication Date: 10/24/2023
Citation: Marek, G.W., Evett, S.R., Colaizzi, P.D., O'Shaughnessy, S.A., Brauer, D.K., Ruthardt, B.B., Copeland, K.S., Howell, Sr., T.A. 2023. Differences in crop coefficients for SDI and sprinkler irrigation [abstract]. ASABE 2nd Global ET Symposium, October 23-27, 2023, University Park, Pennsylvania. Paper No. 23032.

Interpretive Summary:

Technical Abstract: The use of crop coefficients (Kc) based on standardized reference evapotranspiration (ETo) is a widely accepted method for estimating daily crop water use. However, Kc for subsurface drip irrigation (SDI) may be smaller than those developed for sprinkler irrigation. We present and discuss lysimeter-derived Kc for corn and sorghum grown on MESA (mid-elevation sprinkler application) and SDI-irrigated large weighing lysimeters at the USDA-ARS Conservation and Production Research Laboratory near Bushland, TX. Although differences were greatest during the vegetative growth period when evapotranspiration (ET) was dominated by evaporation (E) from the wetted soil surface, considerable E losses from plant and soil surfaces occurred with MESA even after maximum leaf area was reached. Subsequent comparison of ET following MESA and LESA (low-elevation sprinkler application) events with ET from SDI also helped quantify E losses associated with sprinkler irrigation throughout the growing season. The Kc values for SDI were consistently less than those for MESA overall, warranting a 10% discounting of irrigation depths calculated using Kc values developed using sprinkler irrigation. As such, use of sprinkler-derived Kc for SDI may result in over irrigation.