Irrigating Turf With Effluent (Salty) Water. James A. McAfee, Ph.D. Extension Turfgrass Specialist Texas AgriLife Extension Service Dallas, Texas

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1 Irrigating Turf With Effluent (Salty) Water by James A. McAfee, Ph.D. Extension Turfgrass Specialist Texas AgriLife Extension Service Dallas, Texas

2 Presentation Objectives Define Reclaimed Water Discuss Pro s and Con s of Using Reclaimed Water Discuss Testing for Irrigation Water Quality Discuss Problems Caused by Excess Salinity and/or Sodium Discuss Management Programs for Salinity Affected Soils

3 Reclaimed Water Reclaimed Water: wastewater effluent urban water reuse recycled water Additional Terms: gray water black water rainharvesting

4 RainHarvesting

5 Why Increased Interest in Using Reclaimed Water for Turfgrass Save potable water supply Avoid water restrictions Cost savings? Addition of turfgrass nutrients

6 Water Restricted Due to Drought Conditions

7 Concerns with Using Reclaimed Water for Sports Fields Water quality Irrigations system needs Applications restrictions/monitoring Continuous supply, even if not needed Soils

8 Reclaimed Water (treatment stages) Primary Secondary Tertiary

9 Irrigation System (New/Retrofit)

10 Important to Have Filters on Irrigation System

11 Posting Fields Using Reclaimed Water

12 Restrictions/Monitoring Hours of irrigation determined by city usually nighttime only Daytime irrigation generally have to have someone on site to monitor fields Special irrigation needs: overseeding watering in preemergent applications watering in insecticide application (grubs)

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14 Excess Reclaimed Water

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17 Salinity/Sodium Soil Problems

18 Testing Reclaimed Water Testing by wastewater producers: Biological oxygen demand (BOD) turbidity bacterial counts (pathogens) Agronomists/Horticulturists: electrical conductivity (ECw ) sodium adsorption ratio (SAR) carbonates, bicarbonates

19 Irrigation Water Quality Guidelines Potential problems: Salinity Ecw (conductivity) TDS Specific ion toxicity Na Cl B carbonate, bicarbonate levels Nutrients (N, P, K, Ca, Mg, micros) ph

20 SALT LEVELS IN IRRIGATION Hazard Class ECe (dsm-1) TDS (ppm) low < 0.75 < 500 medium ,000 high ,000-2,000 very high > 3.0 > 2,000

21 Field Salinity Meter

22 Other Potential Sources of Salts Soil minerals Well water Lakes Fertilizers (small) Flooding

23 Sodium Adsorption Ratio (SAR) relationship between Na, Ca, Mg in water measured in meq/l 10 meq/l or less, okay for irrigation purposes meq/l, could be problems with Na accumulation in soil > 26 meq/l, don t use if at all possible

24 Residual Sodium Carbonate (RSC) Relationships between carbonates/bicarbonates and calcium/magnesium in water Formula: RSC = (CO3 + HCO3 ) ( Ca + Mg ) RSC: 0 to 1.25 meq/l, safe for irrigation 1.25 to 2.5 meq/l, marginal for irrigation > 2.5 meq/l, not suitable for irrigation

25 SALINITY TOLERANCE OF POPULAR TURFGRASSES (Turgeon, 2002) HIGH (Cool Season) (Warm Season) Tall fescue Perennial ryegrass Fine fescues Creeping bentgrass Kentucky bluegrass Rough bluegrass Colonial bentgrass Seashore Paspalum St. Augustinegrass Zoysiagrass Bermudagrass Buffalograss Centipedegrass Bahiagrass LOW

26 Managing Sports Fields With Salinity/Sodium Issues Drainage!!!!!!!!!!!!!!!!

27 Install Drainage System (leaching salts)

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29 Turfgrass Irrigation

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31 Football Field Audit Zone Precipitation Distribution Rate Uniformity

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33 Leaching Requirement (salts present in irrigation water) LR = ECw /5ECe - Ecw Ecw = electrical conductivity of water Ece = soil level that starts affecting plant growth by at least 10%

34 Using LR to Calculate Irrigation Needs (Example) El Paso: 9 inch deficit for month of June equals 2.25 inches per week deficit crop coefficient of 60% need 1.35 inches of water per week assume a LR of 15% 15% X 1.35 =.2 inches Total weekly irrigation needs equals: = 1.55 inches per week

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37 Aerification Practices

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39 Steps to Improve Turfgrass in Salt-affected Soils Regular testing of water source and soils Restrict use of poor quality water Select salt tolerant turfgrasses Leaching of salts and maintaining drainage Intensive cultivation practices Modifications with soil and water amendments Adjusted cultural practices

40 Other Cultural Practices Fertilization program Mowing progam

41 Case Study

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43 Irrigation Water Source

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45 Water Analysis Report Analysis Results Degree of Restriction Salinity Ecw (ds/m) slight TDS (mg/l) 600 slight SAR 34 very severe Chloride (ppm) 39 low Boron 0.61 low RSC 6.17 very severe level

46 Water Analysis Report (continued) Analysis Results Lbs. Nutrient per (ppm) acre-foot of water* Nitrate-N Phosphorus Potassium 4.25 Calcium Magnesium * one acre-foot of water equals 325,000 gals.

47 Soil Test Report (same site) Analysis Results Rating ph 8.9 Very high Phosphorus 1,626 ppm Very high Potassium 343 ppm high Calcium 15,204 ppm Very high Magnesium 188 ppm high Salinity 924 slight Sodium 1,465 ppm high Boron 3.92 ppm high

48 Rebuild Field

49 Sideline Drains

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51 Adding Sand ( 7 inch depth )

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53 Planting Big Roll Sod

54 First Home Game Preparation

55 Summary Using reclaimed water, always check source Drainage is the key to managing salinity and/or sodium problems Test water source and soils on a regular basis