Soil Moisture Uniformity

Transcription

1 Spr rinkler Irrigation & Soil Moisture Uniformity Michael D. Dukes, Ph.D., P.E., C.I.D. Melissa Haley, Stephen Hanks Nov. 6, 2006, IA Int l Irrig. Show, San Antonio, TX

2 Background Population served by public supply 5.4 million million million ~1,000 people/day 11% U.S. new home construction in FL FL uses the most groundwater in the US U.S. Most new homes in FL include irrigation ~60% household h water use for irrigation i High quality landscapes and low water holding capacity lide 2

3 Florida s Water Crisis Water Resource Caution Areas: places where water is either scarce or contaminated t as defined by Florida s Water Management Districts lide 3 Adopted from: Purdum, E.D Florida Waters: A Water Resource Manual from Florida s Water Management Districts. Brooksville, Fl.

4 Sensor Based Irrigation Soil moisture sensors (SMS) lide 4 Evapotranspiration (ET) based controllers

5 Current Turf/Landscape Irrigation Rese earch 1. SMS plots, Gainesville 2. Rain Sensor evalu ation, Gainesville 3. SMS plots & ET controllers, Citra (Turfgrass Resear rch Unit) 4. SMS on cooperating homes, Pinellas Co. 5. SMS development scale, Lake Jovita, Pasco Co. 6. ET controller plots, GCREC Hillsborough Co. lide 5

6 Potential Uniformity Impact Root Zone Soil Be elow Root Zone Adequate irrigation Non-uniformity (100% uniformity not practical) Under irrigated Over irrigation lide 6

7 Improper p Coverage lide 7

8 Narrow Areas lide 8

9 Catch Can Testing lide 9

10 Literaturee Review Analytical yield & uniformity relationship Yield reduction due to non-uniformity not well documented in the field Redistribution of irrigation water within canopy (ag. crops) Minimal information on turf quality & uniformity lide 10

11 Turf Quality & Non-uniformity lide 11

12 Plots Methodology 4.6 m X 4.6 m (15 ft X 15 ft) 15Q Spray heads 25 catch cans Tests at 3 pressure es 414 kpa (60 psi) 138 kpa (20 psi) 69 kpa (10 psi) lide 12

13 Experime ental Site lide 13

14 Arredondo FS Field capacity 7-10% (no runoff) Permanent wilting point 2-3% Infiltration i rate 179 mm/hr (7 in/hr) V low25% DU lq = Vavg Methodology lide 14

15 Testing Conditions Soil moisture content Gravimetric 10 cm (4 in) long X 5.7 cm (2.2 in) dia. TDR 20 cm (8 in) long rods Soil sample & TDR collection rotated 90 deg. Soil sample locatio ons repacked Low wind (< 2.5 m/s; 5 mph) lide 15

16 Uniformity Data Collection lide 16

17 PRE Irrigation DUlq R 2 = psi 20 psi 0.90 POST Dec 17-Feb 8-Apr 28-May 17-Jul 5-Sep 25-Oct 14-Dec Date GRAV-DU TDR-DU CC-DU 0.50 DUlq 0.40 Effect on DU lq R 2 = R 2 = lide psi 20 psi 10 psi R 2 = Dec 17-Feb 8-Apr 28-May 17-Jul 5-Sep 25-Oct 14-Dec Date GRAV-DU TDR-DU CC-DU

18 Statistical Results Interaction between measurement type & pressure level on DU lq Gravimetric TDR Catch hcan lide 18

19 Pressure Effect on Distribution Pres. TDR Pre-Irr. Unifo ormity Grav. Pre-Irr. TDR Grav. Post-Irr. Post-Irr. Can Catch Can (psi) DU lq a 0.83 a a 0.86 a a 0.81 a 0.74 a 0.83 a 0.63 a 0.79 a 0.83 a 0.55 b 0.75 a 0.69 b 0.39 c Different letters indicate a significant difference within columns lide 19

20 Pressure Effect on Soil Moisture Content Pres. (psi) TDR Pre-Irr. Grav. Pre-Irr. TDR Grav. Catch Post-Irr. Post-Irr. Can (m 3 /m 3 ) (in) a 0.07 a a 0.09 a a 0.08 a 0.15 a 0.20 a 0.72 a 0.11 b 0.17 b 0.47 b 0.09 b 0.15 c 0.39 c Different letters indicate a significant difference within columns lide 20

21 Effect of Irrigation on Soil Moisture Change in Soil Moistur re Content (m 3 /m 3 ) y = x R 2 = R 2 y = x R 2 = Irrigation Vol (ml) GRAV TDR lide 21

22 PRE TDR SMC vs. (m 3 /m 3 ) TDR Θ Gravimetric SMC 0.05 R 2 = POST Gravimetric Θ (m 3 /m 3 ) TD DR Θ (m 3 /m 3 ) R 2 = lide Gravimetric Θ (m 3 /m 3 )

23 TDR Soil Mo oisture DUlq re DUlq Catch Can DU lq Residential Rotor Spray CC DUlh 0.40 lq Soil Moistur 0.30 Residential Testing Grav = CC-DUlq R 2 = Grav = CC-DUlh R 2 = U lh = (0.614 * DU lq Plot Testing ) Catch Can DU lq lide 23 Gravimetric TDR CC DUlh-Grav CC DUlh-TDR

24 Conclusions SMC uniformity relatively insensitive to irrigation uniformity levels tested here (CC DU lq ) CC DU lh approximates SMC DU lq CC DU lh may be a reasonable indicator of irrigation system performance lide 24

25 Microirrigation Uniformity Testing lide 25

26 Microirrigation Uniformity Testing cont d lide 26

27 Microirrigation TDR DU lq vs CC DU lq lide 27

28 Quest tions? Thank you! Acclima, Inc., Lawn Logic, Rain Bird, Toro, Hydropoint, ETWater, We eathermatic ti SWFWMD, Hillsborough Co o. Water Dept., Pinellas Co. Utilities Danny Burch, Numerous undergrad and graduate students lide 28 s.ufl.edu irrigation.ifas.ufl.edu