Water Resources Research Act Program

Details for Project ID 2019OK220B

Effects of deficit irrigation on water use of warm season turfgrasses under fairway maintenance

Institute: Oklahoma
Year Established: 2019 Start Date: 2019-03-01 End Date: 2020-02-29
Total Federal Funds: $5,000 Total Non-Federal Funds: $10,062

Principal Investigators: Charles Fontanier

Abstract: Problem Statement: Deficit irrigation attempts to limit water use in turf by applying water at a lower rate than the predicted water use rate while still maintaining acceptable turf coverage, visual characteristics, and playability. Many current irrigation planning tools rely on reference evapotranspiration (ETo) calculated from meteorological data and a crop specific coefficient to estimate the evapotranspiration of a crop in the field (ETcrop). The current knowledge about warm season turfgrass ETcrop rates under diminishing soil moisture content is limited. This has resulted in 74% of golf courses that “keep turf drier than in the past,†but only 17.9% that use evapotranspiration data of any kind from onsite weather stations. Objective: 1. Quantify water use of key warm season turfgrasses as affected by deficit irrigation practices. 2. Develop a more accurate predictor of ETcrop under diverse irrigation management plans. Methods: Eight warm season turfgrasses, 7 bermudagrasses (Celebration, Latitude 36, OKC 1403, Premier Pro, TifTuf, Tifway, and U-3), and 1 zoysiagrass (Meyer) have been established at the Turfgrass Research Center in Stillwater, OK, using a randomized complete block design with three replications. Irrigation treatments will be applied as a strip-plot once weekly based on a basic water balance model at a rate of 25%, 50%, 75% or 100% ETcrop replacement. Surface and subsurface soil moisture content, Normalized Difference Vegetation Index (NDVI), Normalized Difference Red Edge index (NDRE), visual turf quality, and visual leaf firing will be measured twice weekly. Digital images will be taken for analysis of percent green cover once weekly. Expected Outcomes: This research will contribute towards a better understanding of water use rates of warm season turfgrasses under drought stress and lead to improved recommendations for deficit irrigation practices. That will include a system to predict accurately ETcrop under different irrigation regimes. This will fill the knowledge gap that exists and give turfgrass managers the information they need to be able to more widely adopt deficit irrigation practices. Ultimately, increased use of deficit irrigation programs will result in less water used for golf courses and similar turfgrass sites.