Project Final Report Submitted to Denver Water. Project Title: Soil Baseline Study on Landscape Water Reuse Sites

Transcription

1 Project Final Report Submitted to Denver Water By Yaling Qian, Associate Professor Department of Horticulture and Landscape Architecture Colorado State University July 1, 2005 Project Title: Soil Baseline Study on Landscape Water Reuse Sites BACKGROUND To ensure sustainable and affordable water supplies, Denver Water has completed a wastewater recycling system that treats and delivers recycled wastewater for landscape irrigation and other reuse purposes. Reuse of treated wastewater for irrigating landscapes is one of the approaches to maximize the existing water resources and stretch current urban water supplies. Phase one of the wastewater Recycling System has provided reclaimed wastewater to Swansea Park, Dunham Park, Bruce Randolph Middle School, Schaefer Park, Park Hill Golf Course, City Park Golf Course, and the Denver Zoo via 12 miles of pipeline. Recycled wastewater was also put into the City Ditch, which supplies irrigation water to Washington Park, the Denver Country Club and City Park. 1

2 Sponsored by Denver Water, we have conducted a project to collect and test soil samples from the parks, golf courses, and other facilities that use this recycled wastewater for landscape irrigation to establish soil baseline information. The information collected can be used to study changes that may occur in the soils after recycled wastewater is used for many years. SAMPLING PROCEDURES A total of 96 soil samples were collected in August 2004 to test soil chemical properties. The soil sampling sites were marked on maps for individual facilities. At each sample site, three cores were collected using a hand-held boring tool. At parks and schools, samples were taken at 0-20 and cm depths; at golf courses, samples were taken at 0-20, 20-40, 40-60, 60-80, and cm depths. At Washington Park, samples were only taken to 0-20 cm depth, because of the Facility Manager s concerns about damage to wires buried underground. Three cores at each site and depth were combined. Metal rods were buried at each sampling site as a future location reference. The following maps indicate the sampling sites at the 10 landscape facilities. 2

3 2 200 yd yd 100 yd 10 Site 1: Fairway #2, Sampled at 20 ft east of the 200 yardage marker from the green. Site 2: Fairway #8, Sampled at 20 ft east of the 100 yardage mark. Site 3: Fairway #10, Sampled at 20 ft west of the 100 yardage mark. Sampling location North Bruce Ranodolph Middle School Site ft Site ft Site ft East Power house Form a line between the northwest corner of powerhouse and the northeast corner of the building west of the school. Sampled at 150, 300, and 450 ft from the northwest corner of the powerhouse 3

4 Fairways #2: sampled at 20 ft south of the 175 yd irrigation head. Fairway #14: sampled at 20 ft north of the 120 yd irrigation head. Fairway #16: sampled at 20 ft north of the 121 yd irrigation head. Fairway #18: sampled at 20 ft south of the 120 yd irrigation head. City Park ft ft ft ft ft ft Sites 1 and 2. Started at the edge of the pavement looking at the statue of a man holding a sword. Measured due North toward a metal light post. Sampled at intervals of 150 and 300 ft. Sites 3 and 4. Started at the Northwest of the Dr. Martin King Monument. Measured from the edge of pavement toward edge of tennis courts. Samples were taken at intervals of 150 and 300 ft. Sites 5 and 6. Started from the light pole located next to a rock bridge. Measured from the light pole in line with the Southeast corner of the Natural History Museum. Samples were taken at 150 and 300 ft. 4

5 Site ft Site 1. Started at the Northwest corner of Dos Chappell Bath House, on the line in between the meeting of two sidewalk slabs. Measured northeast in line with green light pole, at 150 ft. Site 5 Site ft Site 2 Site ft 250 ft 150 ft Sites 2, 3, 4, and 5. Started at light pole by crosswalk with intersection of Dowing and Kentucky to the west. Measured northeast, in line with the southeast corner of the white building. Sampled at intervals of 150, 250, 350, and 450 ft. Site 6. Started at southwest base point of the white bridge on the east side of the road/bike path. Measured southeast, in line with the second white bridge s southwest base point, at 150 ft. Site ft Denver Zoo Site 3 Site 2 Site 1 Site #1: sampled under an ash tree located northwest of the lion maternity gate. Site #2: sampled under an ash tree located at northeast of the lion maternity gate. Site #3: sampled right inside of the Denver Zoo main entrance, under a small ash tree. 5

6 Site 1: Fairway #3, sampled at 10 ft south of the 216 yds (from green) irrigation head. Site 2: Fairway #14, sampled at 10 ft north of the 265 yds irrigation head (from green). Site 3: Fairway #17, sampled at 10 ft north of the 165 yds irrigation head. Site 3 109ft 87 ft 7 in ft Site 1 Site ft 75 ft 1 in 230 ft Site 1: the intersection of 117 ft 8 in east of concrete of the central playground and 75 ft 8 in north of 37 Ave. Site 2: the intersection of 230 ft west from the fence metal pole (parallel to power pole) and 75ft 1 in. north of 37 Ave. Site 3: the intersection of 109 ft 6 in west of power pole and 87ft 7 in north from 37 Ave. 6

7 Site ft Site ft Site ft Sites 1, 2, and 3. Start at the northwest corner of the building located south of the park. Then line up with southwest corner of the storage building in the center of the park. Sampled at 100, 200, and 300 feet from the northwest corner of the south building. 50 ft Site 3 50 ft Site 2 50 ft Site 1 Light pole Light pole Sites 1, 2, and 3. Form a line between the light pole on the side walk close to Clayton Ave. and the light pole on Thompson Ave. Starting from the light pole on the side walk close to Clayton, sampled at 50, 100, and 150 ft from the light pole. 7

8 SOIL ANALYSIS All soil samples were allowed to air dry, then ground, and screened to pass through a 10-mesh (2 mm) sieve. Soil samples were tested at the Soil, Water, and Plant Testing Laboratory at Colorado State University. Parameters of each soil sample tested included o Boron o Chloride o Nitrate nitrogen (NO 3 -N) o Phosphorous o Electrical Conductivity o Sodium o Sodium Absorption Ratio o ph o Calcium o Magnesium o ESP (exchangeable sodium percentage) Soil Boron and Chloride Content: Soil boron and chloride content is extracted using hot water (1 g of soil to 10 ml of hot water). Hot water helps to dissolve boron. After filtering, Boron was measured by using an inductively-coupled plasma-atomic emission spectroscopy (ICP). Chloride was measured using ion chromatography (Dionex, 2000 I/SP ion chromatograph, Sunnyvale, CA). 8

9 Soil ph, Electrical Conductivity, water extractable Ca, Mg, and Na, and Sodium Absorption Ratio (SAR): Soil ph and EC were analyzed using a saturated paste extract. Deionized water was added to ground and sieved soil and mixed uniformly until a saturated paste was obtained. [At saturation, the soil paste glistens, flows slightly when the container is tipped, and slides cleanly from a spatula. A trench carved in the soil surface readily closes after a spatula is passed through it]. The ph of the paste was taken directly by placing the ph electrode into the paste. The saturated paste was then transferred to a Buchner funnel with Whatman 1 filter paper and vacuum filtered. The filtrate (saturation paste extract) was collected in a liquid scintillation vial. The EC was taken by pouring the extract into the EC cell and recording the reading of the electrical conductivity meter. The saturated paste extracts were transferred to auto-sampler tubes and analyzed for Ca, Mg, K, and Na concentrations by ICP. The SAR was calculated as: Where values of Ca, Mg, and Na are expressed as meq/l. Soil Organic Matter Content: Soil organic matter was determined using a modified Walkley-Black method by reacting soil organic matter with potassium dichromate (K 2 Cr 2 O 7 2 ) and sulfuric acid. The 9

10 redox reaction changes the original chrome 6 (orange) to chrome 3 (greenish). The mixture was allowed to settle and the liquid was poured off into spec20-tubes. The samples were then analyzed for percent transmittance at 610 nm using a Spectronic 20D Spectrophotometer. Extractable Soil Nitrate and Phosphorus: Soil samples were extracted using the ammonium bicarbonatediethylenetriaminepentaacetic acid (AB-DTPA extractant). The AB-DTPA solution was made with 1M NH 4 HCO M DTPA at ph 7.6. Ten grams of air-dried soil was mixed with 20 ml AB-DTPA extracting solution and placed on a mechanical shaker for 15 minutes. After filtering, the extracts were measured for extractable P at 882 nm on a Spec 20 at an acidity of 0.18 M H 2 SO 4 by reacting a sample aliquot with ammonium molybdate using ascorbic acid as a reductant in the presence of antimony. Nitrate-N content was determined using flow-injection Cd reduction analysis. This method is based on the reduction of injected nitrate to nitrite and determination of nitrite spectrophotometrically at 540 nm. (Note: Nitrate is reduced with cupperized cadmium in the presence of sulfanilamide and N-(1-naphthyl)-ethylenediamine dihydrachloride to nitrite forming a pink color). In addition, AB-DTPA extracted K, Zn, Fe, Mn, and Cu were measured by ICP. 10

11 Cation Exchange Capacity and Exchangeable Sodium Percentage: CEC Measurements: Cation exchange capacity (CEC) was measured using a modified version of method 8-3 in Methods of Soil Analysis. Part 2. Chemical and Microbiological Properties. Second edition. A.L. Page, et al. (eds). American Society of Agronomy, Inc. Soil Science Society of America, Inc. Madison, WI Chapter 8. Cation Exchange Capacity. J.D. Rhodes.Pp A vacuum filtration device (Concept Engineering, Lincoln, NE) was used where 2.5 g of soil was weighed into a 50 ml syringe containing approximately cm of glass wool. The syringe was attached to the filtration device. An initial saturation step was performed where approximately 40mL of 0.5N sodium acetate - 0.1N sodium nitrate (ph 8.2) was added to the syringe containing the soil and allowed to pass through the soil when a vacuum was placed on the system. After the initial saturation step was completed, approximately 40mL of ethanol was passed through the soil to rinse out excess sodium. Following the alcohol rinse step, a final exchanging step was done where exactly 50 ml of 0.5N magnesium chloride was passed through the soil and retained for sodium and nitrate analysis. Sodium was analyzed by ICP and nitrate was analyzed by flow injection analysis. The CEC was determined by subtracting meq of nitrite entrained in the final exchanging step from meq of sodium and expressed as meq/100g. Exchangeable Sodium Measurement: Five grams of air-dried and sieved soil was weighed, and placed in a 40 ml centrifuge tube. Then 25 ml of 1 N ammonium acetate solution (ph 7.0) was added. The 11

12 mixture was shaken for 30 minutes on a reciprocating shaker. The solution was allowed to settle and than filtered through Whatman #1 filter paper. The soil extract was then analyzed for exchangeable Na by ICP. Exchangeable sodium percentage (ESP) is calculated by dividing exchangeable sodium by CEC. Soil Texture Estimation: Soil texture was estimated using the "feel" method by a soil scientist with 25 years experience. Between Labs Comparison: To verify our analysis results, 10 soil samples (~10% of total # of soil samples) were analyzed in two labs, the Servi-Tech Laboratories, Dodge City, KS and the Soil, Water, and Plant Analysis Lab at Colorado State University, for a comparison. Each of the 10 soil samples was grounded and sieved, then evenly divided into 2 portions and sent to the two labs for analyses of boron, chloride, phosphorous, EC, SAR, ph, calcium, magnesium, and ESP. The methods used at CSU lab were described previously. In the Servi-Tech Laboratories, the methods for B, Cl, SAR, ph, and exchangeable sodium were the same as the CSU lab. However, different methods were used for P and CEC measurements. For soil P analysis, the Olson s method was used. For CEC analysis they used summation method. 12

13 Soil Sample Collections In 2005 After analyzing all the soil samples and sending 10% of the soil samples to a lab other than Colorado State University for verification of results, we found some soil samples that we collected in 2004 were not of sufficient quantity for future analysis. Additional samples were collected at the same locations in 2005 and stored for future reference. 13

14 RESULTS All original soil baseline data were presented in APPENDIX A (including datasheets #1-#9) at the end of the report. Following, I briefly highlight some of the results. Soil texture: Soil samples collected indicated that the soil texture of Swansea Park, Dunham Park, Schaefer Park, and Bruce Randolph Middle School are dominated by sandy loam. Soil texture in Park Hill Golf Course and Denver Country Club is mainly loamy sand and sandy loam. The coarse soil textures will aid in salt leaching on these sites as long as a shallow water table is not present. Soil texture in City Park and Washington Park ranged from loam to clay. Electrical conductivity (EC): Electrical conductivity of the saturated soil paste extract is the most reliable indicator of soil salinity level (Carrow and Duncan, 1998). In general, electrical conductivity of soil higher than 4.0 mmho/cm (ds/m) is considered saline soil. However, salt sensitive plants may be injured below this value and salt tolerant plants may tolerant EC levels higher than 4 mmho/cm. Previously, Qian et al. (2002) reported that the salinity levels that caused 25% shoot growth reduction of Kentucky bluegrass cultivars ranged from 3.2 ds m -1 to 4.7 ds m -1. All samples collected from the 10 sites in 2004 had an EC < 4.0 (ds/m), although soil salinity on Bruce Middle School playground, Park Hill Golf Course, and Denver Country Club is higher than at other sites. Exchangeable sodium percentage (ESP) and sodium adsorption ratio (SAR): Both ESP and SAR are indicators of sodium hazard for soil. Exchangeable sodium percentage is calculated by dividing exchangeable sodium by cation exchange capacity 14

15 (CEC). Sodium adsorption ration is reported as a special ratio of sodium to calcium plus magnesium of saturated paste extraction. An ESP or SAR value of 15 or greater indicates sodic soil with excessive sodium in soil particles. Excess sodium can cause soil to be hard and cloddy when dry, to crust badly, and to absorb water very slowly. High ESP or SAR can reduce soil permeability and water percolation rate. Salt leaching would become less effective when soil percolation and infiltration rates are reduced. Sometimes, sodium can initiate deterioration of soil structure at ESP well below 15. ESP that is greater than 9 can cause problems on fine-textured (clay) soils over time, on highly trafficked sites, or when irrigation water is too pure. (When water is too pure, there are few cations to counteract with Na). All samples collected from the 10 sites in 2004 had an average ESP of 2.65% with maximum of 7.1 and minimum of 0.9%. The baseline soil SAR and ESP were highest on Park Hill Golf Course with its average SAR and ESP 5.4 and 5.2, respectively. Among all sites, soil samples from City Park and Denver Zoo exhibited the lowest SAR and ESP (1.5 and 1.6, respectively). SAR and ESP on other sites ranged from and Soil B: Mass (1978) provides guidelines for B content in soils. Sensitive plants (such as some fruit trees) will show growth decline as soil B exceeds mg/kg. Moderately sensitive plants will start to decline when soil B exceeds mg/kg. Kentucky bluegrass can tolerate soil B content at mg/kg. All samples collected from the 10 sites in 2004 had an average soil B content of 0.66 mg/kg. Soil samples collected from Park Hill Golf Course exhibited soil B content of 2.0 mg/kg, which is higher than other sites and could result in decline of moderately sensitive plants. Soil samples from City Park, Swansea Park, and Dunham Park had

16 mg/kg soil B content, well below levels that adversely affect plants. B content on other sites ranged from mg/kg. Soil P: With the AB-DTPA test that is used at the Soil, Water, and Plant Testing Lab at CSU, the critical values for determining soil P levels (to 8- inches deep soil) has been set as low (0-3 ppm), medium (4-7 ppm), high (8-11 ppm), and very high (exceeding 11 ppm). P is typically a lot higher at the surface. Of all the soils sampled in 2004, 44% were ranked in the very high P category (>11 ppm). 67% of the 0-20 cm soil samples were ranked in the very high P category. Since recycled wastewater also contains P, P fertilization in these sites should be reduced or limited. Between Labs Comparison: To verify analysis results, 10 soil samples were collected from 2 golf courses. Each of the 10 soil samples was grounded and sieved, then evenly divided into 2 portions and sent to the two labs for analyses. The results were presented in APPENDIX B. For most of the parameter tested, there exist very good correlations between the two labs with the correlation coefficients ranging from to (please note: a correlation coefficient of 1 indicates perfect matches between the 2 labs). Boron content, SAR, ESP, soil ph values of individual soil samples from the two labs were very similar to each other. Soil chloride content, however, showed the greatest deviation among all parameters tested. 16

17 SUMMARY AND RECOMMENDATIONS The issues surrounding recycled wastewater irrigation are complex and further research is needed to provide more information. Both problems and opportunities exist in using recycled wastewater for landscape irrigation. Water reuse in urban landscapes is a powerful means of water conservation and nutrient recycling, thereby reducing the demands of freshwater and mitigating pollution of surface and ground water. Two main concerns over the use of recycled wastewater for irrigation remains. Those are 1) potential problems caused by excessive sodium and salinity, and 2) excessive nutrients or nutrient imbalance. Soil salinity is a function of soil type, management, salinity of water used for irrigation, and the depth of water table. Clay soil is more prone to salt accumulation and sodium deterioration. Shallow water table can reduce leaching and introduce salts to the root zone. Therefore, the most salinity susceptible sites are sites with shallow water table, high clay content, poor drainage, and great soil compaction. Management practices that reduce water table, cap the topsoil with sand (especially for sports practice fields), improve drainage, and reduce compaction will reduce the potential sodium problems. In the 10 water-reuse sites that we studied, many sites have sandy soil texture, which have the advantage of reducing salinity or delaying the occurrence of the potential problems. Based on our previous experiments and literature review (Lazarova and Bahri, 2005). The following are the best management practices that I recommend: Water and soil quality monitoring: Regularly monitor water and soil quality with water quality enforcement guidelines. 17

18 Irrigation: Adequate leaching and provide sufficient drainage to remove excess Na and salts from the root zone; Careful irrigation based on evapotranspiration and leaching requirements; Conversion to low angle nozzle to reduce leaf damage on trees and shrubs; Select appropriate irrigation frequency to avoid frequent wetting and drying cycles on the tree leaves; Blending conventional water with treated RWW or use the two sources in rotation; Dual plumbing to irrigation greens with conventional water in cases of excessively high SAR or high salinity, as a last resort. Compaction controls: More intensive cultivation programs (deep aeration and water injection) to maintain oxygen diffusion and water movement; More vigorous traffic control programs. Fertilization: Reduced nitrogen and phosphorous fertilization, accounting for the fertilizer value present in recycled wastewater; Fertilize to alleviate nutrient imbalance. Amendments: 18

19 Additional chemical amendments to displace Na and reduce exchangeable sodium percentage; Addition of gypsum to irrigation water to adjust the SAR of irrigation water. Plant selections: Replace with more climate and soil adapted, salt tolerant species and cultivars; Maintain healthy plants healthy plants withstand salinity better. 19

20 REFERENCES Carrow, R.N., and R.R. Duncan Salt-affected Turfgrass Sites: Assessment and management. Ann Arbor Press. Chelsea, MI. Lazarova, V. and A. Bahri Water reuse for irrigation: Agriculture, landscapes and turfgrass. CRC Press. Mass, E.V Crop salt tolerance. In G.A. Jung. (Ed.) Crop Tolerance to suboptimal land conditions. ASA Spec. Pub. 32. Amer. Soc. of Agron., Madison, WI. Page, A.L., R.H. Miller, and D.R. Keeney Methods of Soil Analysis. Part 2 Chemical and Microbiological Properties. Agronomy Monograph no. 9. (2 nd edition). Madison, WI. Qian,Y.L., S.J. Wilhelm, and K.B. Marcum Comparative responses of two Kentucky bluegrass cultivars to salinity stress. Crop Science 41:

21 APPENDIX A (Datasheet #1 -#9) Soil Baseline Study Datasheet # AB-DTPA Facility Site depth ---Paste Paste--- % ppm Texture ph EC OM NO 3 -N P K Zn Fe Mn Cu Estimate mmhos/cm Swansea park Sandy Loam Swansea park Sandy Loam Swansea park Sandy Loam Swansea park Sandy Loam Swansea park Sandy Loam Swansea park Sandy Loam Dunham park Sandy Loam Dunham park Sandy Loam Dunham park Sandy Loam Dunham park Sandy Loam Dunham park Sandy Loam Dunham park Sandy Loam Schaefer park Sandy Loam Schaefer park Sandy Loam Schaefer park Sandy Loam Schaefer park Sandy Loam Schaefer park Sandy Loam Schaefer park Sandy Loam Bruce R School Sandy Loam Bruce R School Sandy Loam Bruce R School Sandy Loam Bruce R School Sandy Loam Note: Denver CC = Denver Country Club; Bruce R School = Bruce Randolph Middle School; Park Hill GC = Park Hill Golf Course, City Park GC = City Park Golf Course. 21

22 Datasheet # AB-DTPA Facility Site depth Paste % ppm Texture ph EC OM NO3-N P K Zn Fe Mn Cu Estimate mmhos/ cm Bruce R School Sandy Loam Bruce R School Loamy Sand Park Hill GC Loamy Sand Park Hill GC Loamy Sand Park Hill GC Loamy Sand Park Hill GC Loamy Sand Park Hill GC Loamy Sand Park Hill GC Sandy Loam Park Hill GC Loamy Sand Park Hill GC Loamy Sand Park Hill GC Sandy Loam Park Hill GC Sandy Loam Park Hill GC Sandy Loam Park Hill GC Sandy Loam Park Hill GC Sandy Loam Park Hill GC Sandy Loam Park Hill GC Loamy Sand City Park GC Loam City Park GC Sandy Loam City Park GC Clay Loam City Park GC Clay Loam 22

23 Datasheet # AB-DTPA Facility Site depth Paste % ppm Texture ph EC OM NO3-N P K Zn Fe Mn Cu Estimate mmhos/ cm City Park GC Clay Loam City Park GC Sandy Loam City Park GC Clay Loam City Park GC Clay Loam City Park GC Clay City Park GC Clay City Park GC Loam City Park GC Clay Loam City Park GC Sandy Clay City Park GC Clay City Park GC Sandy Clay Denver CC Sandy Loam Denver CC Sandy Loam Denver CC Loamy Sand Denver CC Loamy Sand Denver CC Loamy Sand Denver CC Sandy Loam Denver CC Loamy Sand Denver CC Loamy Sand Denver CC Loamy Sand Denver CC Sandy Loam Denver CC Loamy sand 23

24 Datasheet # AB-DTPA Facility Site depth Paste % ppm Texture ph EC OM NO3-N P K Zn Fe Mn Cu Estimate mmhos/ cm Denver CC Loamy Sand Denver CC Loamy Sand Denver CC Loamy Sand Denver CC Sandy Loam Denver CC Sandy Loam Denver CC Loamy Sand Denver CC Loamy Sand Denver CC Loamy Sand Washington park Loam Washington park Loam Washington park Loam Washington park Loam Washington park Loam Washington park Loam City park Clay Loam City park Clay City park Clay Loam City park Clay Loam City park Clay Loam City park Clay Loam City park Clay Loam 24

25 Datasheet # AB-DTPA Facility Site depth Paste % ppm Texture ph EC OM NO3-N P K Zn Fe Mn Cu Estimate mmhos/ cm City park Clay Loam City park Clay Loam City park Clay Loam City park Loam City park Clay Loam Denver Zoo Sandy Loam Denver Zoo Sandy Loam Denver Zoo Sandy Loam Denver Zoo Sandy Loam Denver Zoo Sandy Loam Denver Zoo Sandy Loam 25

26 Datasheet #6 Saturated Paste Extract Exchangeable Hot Water Facility Site depth Ca Mg Na K SAR CEC Na ESP Cl B meq/l meq/100 g meq/100 g % mg/kg Swansea park Swansea park Swansea park Swansea park Swansea park Swansea park Dunham park Dunham park Dunham park Dunham park Dunham park Dunham park Schaefer park Schaefer park Schaefer park Schaefer park Schaefer park Schaefer park Bruce R School Bruce R School Bruce R School Bruce R School

27 Datasheet #7 Saturated Paste Extract Exchangeable Hot Water Facility Site depth Ca Mg Na K SAR CEC Na ESP Cl B meq/l meq/100 g meq/100 g % mg/kg Bruce R School Bruce R School Park Hill GC Park Hill GC Park Hill GC Park Hill GC Park Hill GC Park Hill GC Park Hill GC Park Hill GC Park Hill GC Park Hill GC Park Hill GC Park Hill GC Park Hill GC Park Hill GC Park Hill GC City Park GC City Park GC City Park GC City Park GC City Park GC City Park GC City Park GC City Park GC City Park GC

28 Datasheet # 8 Saturated Paste Extract Exchangeable Hot Water Facility Site depth Ca Mg Na K SAR CEC Na ESP Cl B meq/l meq/100 g meq/100 g % mg/kg City Park GC City Park GC City Park GC City Park GC City Park GC City Park GC Denver CC Denver CC Denver CC Denver CC Denver CC Denver CC Denver CC Denver CC Denver CC Denver CC Denver CC Denver CC Denver CC Denver CC Denver CC Denver CC Denver CC

29 Datasheet #9 Saturated Paste Extract Exchangeable Hot Water Facility Site depth Ca Mg Na K SAR CEC Na ESP Cl B meq/l meq/100 g meq/100 g % mg/kg Denver CC Denver CC Washington park Washington park Washington park Washington park Washington park Washington park City park City park City park City park City park City park City park City park City park City park City park City park Denver Zoo Denver Zoo Denver Zoo Denver Zoo Denver Zoo Denver Zoo

30 APPENDIX B Comparison of soil chemical properties analyzed at the Soil, Water, and Plant Testing Lab at Colorado State University (Lab a ) and the Servi-Tech Laboratories (Lab b ) in Dodge City, Kansas. Soil parameters tested included soil ph, electrical conductivity (EC), phosphorous (P), potassium (K), sodium adsorption ratio (SAR), exchange sodium percentage (ESP), chloride (Cl), and boron (B) content. Sample # ph EC (mmhos/cm) P (ppm) K(ppm) SAR CEC (meq/1000) ESP (%) Cl (ppm) B (ppm) Lab a Lab b Lab a Lab b Lab a Lab b Lab a Lab b Lab a Lab b Lab a Lab b Lab a Lab b Lab a Lab b Lab a Lab b Between labs correlation coefficients (r)