WATER REUSE, SALTGRASS SELECTION, AND CARBON FOOTPRINT OF URBAN TURFGRASS SYSTEMS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1009722
• Project Start Date: Jul 1, 2016
• Project End Date: Jun 30, 2021
• Program Code: [(N/A)]- (N/A)

Recipient Organization
COLORADO STATE UNIVERSITY
(N/A)
FORT COLLINS,CO 80523

Performing Department
Horticulture and Landscape Architecture

Non Technical Summary
Turfgrass, along with other landscape plants, provide many benefits to homeowners. Well-maintained turf can increase the value of a property. The benefits of turfgrass include functional benefits (by providing a visually pleasing, safe playing surface) and environmental benefits (such as decreased cooling costs in summer, soil stabilization, decreased dust, and noise abatement).With increasing population growth and thus an increased demand for fresh water resources, it is important to find alternatives to fresh water use for landscape irrigation. Several conservation methods exist, and include using alternative water resources and finding the right species for landscape plantings. Along with increased interest in landscape irrigation alternatives is an increased interest in carbon footprint of landscape plants, particularly turfgrass - a major component of urban landscapes.Work has been done at CSU to assess the impact of alternative water sources on commonly used landscape plants, including turf. Two different sources of water have been studied. They include "recycled water", which is treated and disinfected municipal sewage water; and "graywater", which is water that has gone through one cycle in laundry, shower, or bath. These alternative waters are generally considered to be safe for landscape irrigation, although both types of water contain dissolved solids to varying degrees. These solids may adversely affect growth of some landscape plants - especially those that are sensitive to the salts. On the other hand, nutrients present in recycled water and graywater and surfactants presented in graywater may have positive impacts if used properly.Our findings indicate that with the use of recycled water for irrigation, there is an increase in soil salinity. The level of salt accumulation in soil depends on several factors including their concentration in irrigation water, amount of water applied annually, amount of natural precipitation, drainage, and the physical and chemical properties of the soil. Some trees and shrubs are particularly sensitive to salts. To determine which trees and shrubs are intolerant of irrigation with recycled wastewater, we will continue to sample and analyze soil and plant tissue samples from sites irrigated with recycled wastewater. Baseline soil samples were collected in 2004-2005. The additional samples will be compared to the baseline numbers to get a feel for changes in soil salinity and nutrient content over time. Likewise we will continue to monitor the quality and growth of landscape plants. It is important to determine which species are tolerant, and which species are intolerant, so appropriate species can be planted.Likewise, we will continue our work of saltgrass improvement. Saltgrass is a native, perennial, deep-rooted warm season grass species that can withstand increased, and even thrive, on elevated salt levels in soil and irrigation water. While tolerant of drought stress and elevated salts, much of the saltgrass collected is unsuitable for turf use. Work is needed to further select saltgrass lines that are dense, uniform, have good color and good turf quality.Along with concern over the conservation of fresh water resources, there has been increased interest in evaluating the carbon footprint of many systems and practices. Turfgrass systems, with the management requirements, are of particular interest. Determining the carbon footprint of turfgrass systems involves examining the fuel and energy use associated with maintaining turf, chemical use and transportation, soil carbon sequestration, etc. Carbon sequestration, which is the ability of an ecosystem to capture and store C as soil organic carbon, is recognized as a key force to mitigate the effects of global climate change. Research has found that turf systems have the potential to sequester significant amounts of C as soil organic carbon. Improper turf management practices can, however, be detrimental to greenhouse gas production. This research project would evaluate the effects of different fertilizer types on greenhouse gas emissions. Through research, we hope to develop management practices for turf that can reduce carbon footprint from turfgrass systems.

Animal Health Component

80%

Research Effort Categories

Basic

(N/A)

Applied

80%

Developmental

20%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
102	2130	1060	100%

Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships;

Subject Of Investigation
2130 - Turf;

Field Of Science
1060 - Biology (whole systems);

Keywords

turfgrass

recycled water

water reuse

salinity

saltgrass

trace gas flux

carbon footprint

Goals / Objectives
The overall goal of the project is to increase turfgrass sustainability by reusing treated wastewater, selecting and using environmental stress tolerant grasses, and reducing carbon footprint in urban turfgrass systems. Objectives:To monitor reuse water constituents, evaluate effects of irrigation with different reuse waters on soil salinity level and sodium accumulation, and evaluate different options for minimizing the negative effects of irrigation with reuse waters;To determine the physiological response of turfgrass to reuse water constituents and further to select turfgrass species, especially elite saltgrass lines, that tolerate reuse water constituents;To determine the greenhouse gas (GHG) budgets and further to select practices that reduce carbon footprint in urban turfgrass systems;To disseminate research findings (including benefits and drawbacks of using reuse waters, relative resistance of different plants to marginal quality water, and best management practices to turf managers, landscape managers, nursery professionals, water managers, and water treatment specialists.

Project Methods
Objective 1: To monitor reuse water constituents, evaluate effects of irrigation with different reuse waters on soil salinity level and sodium accumulation, and evaluate different options for minimizing the negative effects of irrigation with reuse waters.Chemical analysis of reuse waters:Previously, we have sampled and tested recycled water constituents. We will extend the project to further measure of water quality parameters of harvested stormwater, graywater, and recycled water. The water quality parameters of these waters will be compared. Graywater samples will be collected from storage tanks once per year at households applying graywater for irrigation in Colorado. The filtered sample will be utilized for chemical analysis. Likewise, filtered stormwater sample will be utilized for chemical analysis. For water samples we will focus on salinity level, sodium concentration, bicarbonate content, and individual ion elements. The quality and suitability of a given water for landscape irrigation would be evaluated.Soil and plant tissue analyses:We will collect soil and plant tissue samples from sites irrigated with recycled water and graywater. Chemical properties of soil (salinity, pH, exchangeable sodium percentage, sodium, boron, calcium, K and magnesium) will be analyzed. Plant tissues will be tested for sodium, chloride, boron, potassium, and other metal ions. Comparisons of water, soil, and plant tissues between sites that have utilized graywater, recycled water, or freshwater will likely help to determine if salt or specific ion toxicity is the main contributing factors to the decline symptoms of landscape plants.In 2004-2005, we studied soil baseline information for parks, golf courses, and other facilities that just started to use recycled water for landscape irrigation. To follow up, soil samples should be collected from the original sites every 5-6 years to determine what magnitudes of changes have occurred. Assessment will be made to determine if there is any different degrees of decline in landscape plants, and how these declines may relate to tree species, water quality, irrigation methods, and drainage effectiveness. Information on the relative tolerance of different trees to recycled water or graywater irrigation will be generated.The integrated information about the quality of different waters (such as recycled water, graywater, storm water, etc.) combined with information on the relative tolerance of different landscape plants will help landscape managers to select the right species for urban landscapes. The knowledge generated will also help to achieve the goal of applying "the right water for the right use".Objective 2: To determine the physiological response of turfgrass to reuse water and further to select turfgrass species and cultivars, especially elite saltgrass lines that tolerate reuse water constituents, especially soluble salts.Turfgrasses grown under recycled water irrigation will be evaluated for their performance and clippings will be tested for sodium, chloride, boron, potassium, and other metal ions by inductively-coupled plasma atomic emission spectrophotometry (ICP-AES). Chloride content will be analyzed by the Cl- selective electrode. These parameters will be compared to freshwater irrigation to determine any positive or negative impacts and the degree of impacts.Oftentimes, both salinity and poor aeration occur in turfgrass systems with reuse water for irrigation. We will study the interactive effects of salinity and oxygen availability on different turfgrasses. Greenhouse hydroponic experiment and container experiment will be conducted. B.We will continue the effort in selecting elite saltgrass lines for turf and revegetation uses. We will increase the materials selected from the source nursery and the first and the second generation nurseries. Right now we do not have enough materials. We would like to increase materials. After evaluation we will start to plant fields for targeted lines. Data on spread, establishment, growth, and general turf characteristics will be collected to provide information for release of vegetative saltgrassObjective 3: To determine the greenhouse gas (GHG) budgets and further to select practices that reduce carbon footprint in urban turfgrass systems.We will evaluate fuel, electricity, and natural gas use associated with golf course operations. A detailed survey regarding energy use and management practices will be sent to golf courses in Colorado. The survey asks for information, including fertilization practices, acreage types on the course (e.g., native areas, fairways, tees, roughs, and greens), types of fuels used, electricity for irrigation pumping, gallons of water for irrigation, and club house energy uses. By calculating fuel types and quantity used, CO2 equivalency equations can estimate the amount of CO2 released for each energy source. The project will define a course's carbon emissions and the proportions to individual activities. The results of the calculations can be used to identify potential improvements to golf course operations that can reduce the overall footprint.The DayCent ecosystem model will be used to estimate carbon sequestration rates for different types of turfgrass such as native areas, roughs, fairways, and greens on golf courses. The turf-atmosphere exchange of N2O, CH4, and CO2 will be measured by using specialized chambers that have been employed in studies in agricultural systems and native grasslands. Chambers and PVC anchors will be built and installed on putting greens (creeping bentgrass), fairways (perennial ryegrass), rough (Kentucky bluegrass), and native areas (a mix of smooth bromegrass, western wheatgrass, blue grama, and bufflograss). Fluxes of N2O, CH4, and CO2 will be measured by placing vented chambers onto the PVC anchors. Gas samples from inside the chambers will be collected and analyzed. Additionally, the impact of different types of fertilizers on trace gas fluxes will be evaluated.Objective 4: To disseminate research findings including benefits and drawbacks of using reuse waters, relative resistance of different plants to marginal quality water, and best management practices to turf managers, landscape managers, nursery professionals, water managers, and water treatment specialists. We will use the annual Rocky Mountain Regional Turfgrass Conference, the annual Colorado Pro-Green Expo, and the International Society of Arboriculture Annual Conference as the platforms to disseminate research findings including benefits and drawbacks of using reuse waters, relative resistance of different plants to marginal quality water, pros and cons of different turfgrass species, and best management practices. We will make PowerPoint presentations to turf managers, landscape managers, nursery professionals, water managers, and water treatment specialists. Workshops and short courses will be organized in partnership with recycled water providers to inform end users about how water quality can best be evaluated for landscape irrigation.In addition, we plan to write articles for the landscape industry and other relevant trade publications to provide landscape management professionals with information on 1) the impacts and relative tolerance of landscape plants to recycled water and graywater for irrigation, 2) the unique characteristics about saltgrass, and 3) quantitative carbon footprint information of turfgrass systems (including fuel and energy use, soil carbon sequestration and N2O and CH4 emissions) and management practice that maximize beneficial environmental impacts and minimizing negative impacts of turfgrass.

Progress 07/01/16 to 06/30/21

Outputs
Target Audience:Landscape managers, landscape contractors, lawn care professionals, golf course superintendents, parks managers; Home gardeners, Master Gardeners, Extension personnel (agents, regional specialists), and water specialists Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Provided training opportunities for 1 doctoral and 4 MS graduate students. How have the results been disseminated to communities of interest? Provided presentations to green industry about proper landscape plant species selection at the time of landscape planning and during the subsequent replacement of damaged plants when irrigation water quality is marginal. Provided reports to cities regarding the impacts of water reuse on landscape ecosystems. Worked closely withturf and landscape industries to increase awareness of optimal turfgrass management practices andreduced-input management strategies. Communicated research results and promote sustainable practices to the public through conferences, websites, industrypublications, and academic publications. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? A. Water Reuse in Turfgrass Systems Several long-term studies were conducted to evaluate effects of irrigation with different reuse waters on soil salinity and sodium accumulations, and to evaluate different options for minimizing the negative effects of irrigation with reuse waters. Long-term experiment I: To determine the impacts of effluent water irrigation on turfgrass and soils, samples were collected at baseline, 5 and 11 years after the initiation of effluent water irrigation from 3 golf courses, 5 metropolitan parks, and 1 school ground. Soil samples were collected to 1 m deep at 20 cm increments. Concurrently, Kentucky bluegrass clippings were collected for mineral analysis. Soil exchangeable sodium percentage (ESP) and other parameters along the soil profile (1 m deep at 20 cm increments) on four locations that have been subjected to annual gypsum applications were sampled to compare to locations that did not receive gypsum application. Findings: Soil analyses prior to and 11 years after effluent water irrigation indicated that soil sodium content, sodium exchangeable percentage, and soil pH increased after effluent water irrigation. One of the three golf courses had a significant increase in soil salinity (as gauged by soil electrical conductivity) when compared to the benchmark baseline. The increase in soil salinity was not significant at sites with sandy soil. All sites had increased soil pH. Results indicated that the degree of soil pH increase was greater at deeper than at shallow soil depths. In general, soil ESP increased 5 and 11 years of irrigation with effluent water. Eleven years of effluent water irrigation has increased turfgrass clipping sodium content by more than 4 times. Boron and chloride content increased, whereas tissue zinc content was reduced . Despite the significant mineral content changes, turfgrasses generally exhibited good quality. However, there was a linear relationship between turf quality and sodium content in the clippings. We observed salinity stress on some localized sites with fine soil texture and poor drainage under effluent water irrigation. For gypsum treated fairways, the increase in ESP at 0-20 cm and 20-40 cm depths were not statistically significant under effluent water irrigation for 5 to 11 years. The increase became significant from 40 to 100 cm. The changes along the soil profile reflect sodium leaching that effectively prevented a significant increase in soil ESP at the shallow soil depths (0-40 cm). For control sites (effluent water irrigation with no gypsum treatment on site), the increases in ESP from 2004 to 2009 were significant at 0-60 cm depths, with ESP at the 0-20 and 20-40 cm depths being approximately tripled. The relatively high levels of sodium concentration relative to calcium and magnesium in effluent water resulted increased soil ESP, especially at the shallow soil depths. Results from this study indicated that aggressive aerification and gypsum application helped to displace sodium and reduce ESP at the surface depth, although soil ESP increased significantly at deeper soil depths. The fact that the degrees of soil pH and ESP increases were greater at deep soil depth provided reason for concern about possible long-term reductions in soil hydraulic conductivity in fine textured soils, despite the ESP values are not high enough to be classified as a sodic soil. Long-term Experiment IIhas been completed to compare the soil chemical properties of push-up greens and fairways on two golf courses that use either effluent water or fresh water. The study was conducted on two golf courses. Comparison between the two golf courses was emphasized because both courses had the same turfgrass types and were managed by the same superintendent employing similar management practices. The main difference is that Golf course A transitioned to effluent water for irrigation while golf course B has always used fresh water. Over a 10-year period, about 330 soil samples were collected. The soil analyses showed that many changes occurred over time due to the use of effluent water irrigation. After one to seven years of effluent water irrigation, soil sodium, soil electrical conductivity (EC) increased but remained well below the critical threshold levels for turf, whereas soil pH increased. The availability of micronutrients (Fe and Mn) decreased, especially on greens irrigated with effluent water. It is possible that the observed reductions in Fe and Mn availability were associated with soil pH increase caused by effluent water irrigation. On the positive side, effluent contains N, which allowed the turf manager to reduce annual N application by 60 - 70 kg ha-1. This study demonstrated that despite the benefits, there are concerns relating to soil ESP and soil pH increases that could cause reductions in micronutrients availability in the soil. Golf course managers could apply proactive management practices, such as applications of soil amendments that provide Ca to replace Na, use of acidifying products could reduce soil alkalization, and application of micronutrients to lessen the negative impacts. B. Nitrous Oxide Flux in Turfgrass Systems To determine the greenhouse gas (GHG) budgets, A good understanding in trace gas, including N2O flux, in turfgrass systems is essential. The use of slow or controlled-release fertilizers has become very valuable and common practice in maintaining golf course turfgrass. There are different types slow/controlled-release fertilizers with different slow/control release mechanisms. Through the use of urease and nitrification inhibitors, UMAXXstabilizes nitrogen fertilizer, enhances N availability to turfgrass. BCMU is an uncoated balanced methylene urea chain, that requires biological degradation as a slow-release mechanism. POLYON (polymer-coated urea) is acontrolled-release fertilizer that consistently and precisely releases nutrients, making nutrients available when plants need them most. An experiment was completed to quantify N2O emissions from a golf course fairway and rough using three urea fertilizers that utilize different mechanisms to control the release of N. Fertilizers were applied multiple times to a fairway and rough to determine seasonal effects of N2O emissions from the fairway and rough that had different management requirements. Twenty-four plots on the fairway and rough on a golf course were used. Nitrous oxide fluxes were measured using the vented chamber method. Chambers were placed on collars and gas samples were extracted periodically on measurement days. The concentration of N2O was determined using a gas chromatograph. Key findings of the project include: a) Nitrous oxide emission from the fairway was greater than from the rough; b) Summer fertilization with UMAXX and BCMU slow-release fertilizers on fairways produced dramatic and episodic nitrous oxide emission; c) The slow-release formulations for UMAXX and BCMU appeared to be not well controlled in warm and high moisture conditions found on fairways, resulting in episodic release of inorganic N, and therefore, summer fertilizations with UMAXX and BCMU should be avoided during the summer; d) POLYON, a polymer coated urea, had the lowest emission of nitrous oxide when compared with BCMU and UMAXX. POLYON is very effective in consistent N release with much reduced nitrous oxide emission.This research found that nitrogen application during cool temperatures enhances environmentally sensitive management, especially on fairways. For UMAXX and BCMU slow-release fertilizers, golf course managers should avoid summer fertilization to fairways and apply fertilizer in spring and fall. If fertilizer must be applied during summer months to fairways, we recommend POLYON type of controlled-release fertilizer. This study demonstrated that POLYON has well controlled N release mechanisms even in warm and high moisture conditions, which can minimize N loss and reduce N2O emission.

Publications

• Type: Journal Articles Status: Published Year Published: 2021 Citation: Qian, Y.L., & Wilhelm, S. (2021). Compost topdressing to suppress necrotic ringspot and improve the overall health of Kentucky bluegrass lawns. Int Turfgrass Soc Res J, 15. https://doi.org/10.1002/its2.100
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Yaling Qian. 2021. Slow/controlled-release fertilizer applications and nitrous oxide emissions from fairways and roughs. The Reporter (Rocky Mountain Chapter GCSAA) 56 (4):16-18.
• Type: Websites Status: Published Year Published: 2020 Citation: Yaling Qian and Yao Zhang. 2020. Turfgrass under effluent water irrigation: long-term data collection. 2020 USGA Research Summaries. 255-259.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Isweiri H, Yaling Qian, Davis JG. 2021. Interactive effects of waterlogging and salinity on perennial ryegrass and alkaligrass. Int Turfgrass Soc Res J. 2021:110. https://doi.org/10.1002/its2.60

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:Water specialists, landscape managers, landscape contractors, lawn care professionals, golf course superintendents, parks managers; Home gardeners, Master Gardeners, Extension personnel (agents, regional specialists) Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Provided research and training opportunities for undergraduate and graduate students How have the results been disseminated to communities of interest?The research findings have been disseminated to a city water department via a PPT presentation. Research reports have been disseminated to landscape and golf course industries. In addition,publications have been submitted to various journals for publication consideration. What do you plan to do during the next reporting period to accomplish the goals?1) Continue the project for selecting water saving Kentucky bluegrass and tall fescue for Colorado turf industry; 2) Complete a study on methane and nitrous oxide fluxes on golf coursesunder different fertilizer treatments; 3) Completea study on the effects of salinity and water logging on different species of turfgrass.

Impacts
What was accomplished under these goals? In arid and semiarid areas, increase in water demand has forced urban planners to use alternative water resources for turfgrass irrigation. In 2020, a study is completed to compare the soil chemical properties of push-up greens and fairways on two golf courses that use either effluent water or fresh water. The study was conducted on two golf courses. Comparison between the two golf courses was emphasized because both courses had creeping bentgrass (Agrostis stolonifera L.) greens and Kentucky bluegrass (Poa pratensis L.)/perennial ryegrass (Lolium perenne L.) fairways and were managed by the same superintendent employing similar management practices, including mowing height and frequency, total nitrogen and other fertilizers received, and topdressing sand source and amount. The irrigation season was from early April to late October for both courses. The main difference is that Golf course A transitioned to effluent water for irrigation while golf course B has always used fresh water. Golf Course A started to use effluent water for irrigation seven years ago while Golf Course B has always used fresh water. Effluent water was supplied by the city's wastewater treatment plant. Fresh water was raw water from a lake and creek drainage. Over a 10-year period, a total of 238 soil samples of greens (104 from golf course A and 134 from golf course B) were collected, and 90 soil samples (45 from golf course A and 45 from golf course B) were collected from fairways. The soil analyses showed that many changes occurred over time due to the use of effluent water irrigation. After one to seven years of effluent water irrigation, soil electrical conductivity (EC) increased but remained well below the critical threshold levels for turf, whereas soil pH increased by 0.42 units. From 1 to 5 years after effluent water irrigation, sodium levels increased by 2 to 5 times. The availability of micronutrients (Fe and Mn) decreased, especially on greens irrigated with effluent water. Soil phosphorus (P) and potassium (K) levels increased after using effluent water, which would be beneficial for turfgrass and lower fertilization requirements. Overall, the soil analysis of the two golf courses showed that many changes had occurred over time in the greens and fairways due the use of effluent water irrigation. This study demonstrated that using effluent water for golf course irrigation contains risks as well as benefits. Our results showed that soil ESP increased, and soil Na accumulation occurred after the use of effluent water for irrigation despite the application of gypsum. On the positive side, effluent contains N, which allowed the turf manager to reduce annual N application by 60 - 70 kg ha-1. Soil P and K levels increased in the soil after using effluent water, which would be beneficial for turfgrass and potentially lower the fertilizer cost. Another significant change was soil pH. Compared to freshwater irrigation, effluent water irrigation increased soil pH. Soil pH plays an essential role in micronutrient availability to plants. The availabilities of micronutrients such as Fe and Mn were observed to decrease both on greens and fairways, which may eventually lead to micronutrient deficiency. This study demonstrated that despite the benefits of effluent water irrigation, there are concerns relating to soil ESP and soil pH increases that could cause reductions in micronutrients availability in the soil. Golf course managers could apply proactive management practices, such as applications of soil amendments that provide Ca to replace Na, use of acidifying products could reduce soil alkalization, and application of micronutrients to lessen the negative impacts.

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Majed D. Alotaibi, Badr H. Alharbi, Mohammed A. Al-Shamsi, Ali A. Al-Namazi, Saif F. Alharbi, Thobayet, S. Alshahrani, and Y.L. Qian. 2020. Assessing the Response of Five Tree Species Toward Air Pollution. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH 27: 29156-29170
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Sun, T., Z.Q. Jia, H.J. Liu, and Y.L. Qian. 2020. Analysis of correlation between vegetation and morphological characteristics of Nitraria tangutorun Nebkhas at Different succession Stages in a Desert-oasis ecotone. Journal of Lanzhou Univ. Natural Sci. 56: 396-411.
• Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Jay Ham, Ian Aksland, Dylan Casey, Tony Koski , Yaling Qian, and Charles McClelland. 2020. Wireless Soil Moisture Measurement in Turfgrass with Internet-of-Things (IoT) Technology and Low-Cost Sensors. 6th Decennial National Irrigation Symposium. San Antonio, Texas
• Type: Journal Articles Status: Accepted Year Published: 2020 Citation: Hanan Isweiri, Yaling Qian, and Jessica D Davis. 2021. Comparison of fresh versus effluent water irrigation on soil chemical properties of golf course greens and fairways. International Turfgrass Society Research Journal. (Accepted)
• Type: Journal Articles Status: Under Review Year Published: 2020 Citation: Hanan Isweiri, Yaling Qian, and Jessica D Davis. 2021. Interactive effects of waterlogging and salinity on perennial ryegrass and alkaligrass. International Turfgrass Society Research Journal.

Progress 10/01/18 to 09/30/19

Outputs
Target Audience:Water specialists; Landscape managers, landscape contractors, lawn care professionals, golf course superintendents, parks managers; Home gardeners, Master Gardeners, Extension personnel (agents, regional specialists). Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Provided research and training opportunities for graduate students How have the results been disseminated to communities of interest?In 2019, a manuscript titled "Comparison of soil chemical properties prior to and 5-11 years after recycled water irrigation" was published in the Journal of Environmental Quality. The manuscriptwas selected for press release by Crops, Soils and Agronomy (CSA) News. This peer reviewed publication highlighted an 11-year study on the changes in soil salinity, alkalinity, and sodicity along soil profiles from eight urban green spaces in a semiarid Climate. Increasing demand on fresh water supplies in the arid and semi-arid western US and more stringent wastewater discharge standards have made recycled water a common water source for irrigating urban green spaces. The experiment found that average soil EC was 0.82, 0.90, and 1.04 dS m-1 in 2004, 2009, and 2015, respectively. Soil pH was 0.25-0.3 units higher 5 and 11 years after recycled water irrigation when compared baseline. The degree of soil pH increase was greater at deeper than at shallower soil depths. Compared to baseline, samples collected 5 and 11 years after recycled water irrigation had 137% and 100% increase in ESP, respectively, suggesting that sodicity was of greater concern than salinity when recycled water is used for irrigation. On Golf Course I, gypsum application after aerification displaced sodium and reduced ESP at the surface depth (0-20 cm), but soil ESP increased significantly at deeper soil depths. More research is needed to develop techniques to address the risks of soil pH and ESP increases, especially in deep rootzones. This study demonstrated that despite the clear benefits of recycled water irrigation in urban landscapes (water conservation, nutrient recycling, and pollution reduction), there are concerns relating to soil exchangeable sodium (ESP) increase, soil pH increase, and salinity build up. The fact that the degrees of soil pH and ESP increases were greater at deep soil depth provided reason for concern about possible long-term reductions in soil hydraulic conductivity in fine textured soils, despite the ESP values are not high enough to be classified as a sodic soil. As more landscape facilities switch to recycled water irrigation, water providers and landscape managers need to apply proactive practices to ensure continued success in recycled water reuse. What do you plan to do during the next reporting period to accomplish the goals?In 2019, we will continue the project for selecting water saving Kentucky bluegrass and tall fescue for Colorado turf industry; 2) will continue to evaluate and select elite saltgrass lines ; 3) Evaluate methane and nitrous oxide emissions on golf courses under different fertilizer treatments; and 4) evaluate effects of salinity and water logging on different species of turfgrass.

Impacts
What was accomplished under these goals? With a rapidly expanding population and an epic geography dictating Colorado as a head water state, the topics of water use and conservation are ever present to the citizens of Colorado. Selecting species and cultivars that use less water while maintaining acceptable quality will mitigate irrigation demands. Field research is conducted to: 1) compare turfgrass quality and growth of 15 Kentucky bluegrass entries, 19 tall fescue entries, 1 perennial ryegrass line under different irrigation treatments [80% reference ET (ETo), 60% ETo, and 40% ETo] applied twice weekly, 2) determine relative drought resistance of different entries, and 3) document water quantity required for each entry to maintain acceptable and desirable turf quality and thereby assessing their water use efficiency. A full set of replicated study plots, i.e. 9 blocks, with each block consisting of 35 cool season turfgrass entries were established in 2017 with field study conducted in 2018 and 2019. Irrigation at 100% ET was applied during pre-deficit irrigation period (prior to May 31). Deficit irrigation period (irrigation at 40, 60, and 80% ET) starts from June and ends in September, which is followed by recovery period when irrigation amount at 100 to 120% ET water applied. Data were collected weekly on turf quality, water input, green coverage, drought stress symptoms and survival. A light-controlled digital imaging tool and image analyzing software were used to objectively derive turf quality parameters. Research findings to date: During establishment, perennial ryegrass, tall fescue, and Kentucky bluegrass had 72%, 29%, and 1.5% ground coverage at 20 days after seeding. At 30 days after seeding perennial ryegrass had about 90% coverage which is higher than tall fescue (64% coverage). Kentucky bluegrass had only 32% ground coverage. Three months after seeding all three species had great establishment. The total irrigation water was 24, 20, and 15 inches, whereas the total water received (i.e. irrigation + precipitation) was 34, 29, and 25 inches for 80%, 60%, and 40% ET treatments, respectively, in 2018. Based on 2018 data, regression analysis predicted that different Kentucky bluegrass differ in their irrigation requirement (ET level) in maintaining acceptable quality, ranging from 51% to 70 % ET. The irrigation levels to maintain optimal quality ranged from 97 to 120 % ET among Kentucky bluegrass cultivars. Cultivars exhibited lowest irrigation were identified for both bluegrass and fescue. During the initial phase of the project (2018), tall fescue entries showed higher overall quality than Kentucky bluegrass cultivars in all 3 reference ETo treatments while Kentucky bluegrass cultivars showed increased ability to recover from drought. These initial results could be due to tall fescues adapted ability to excavate deeply within the soil profile in water uptake while Kentucky bluegrass adaptively reverts to dormancy in the face of drought stress. However, as study progress to 2019, Kentucky bluegrass had better turf performance than tall fescue. Successive yearly research regimes and data collection are necessary, and study will be continued throughout 2020 to determine the amount of water needed to maintain acceptable quality for each included turfgrass cultivar. As more drought tolerant grasses are selected, we communicate the findings with reginal/national turf industry, and turf managers and sod producers embrace the use of new species and cultivars. The use of improved grasses would decrease the amount of potable water used for landscape irrigation.

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Qian, Yaling and Yuhung Lin. 2019. Comparison of Soil Chemical Properties Prior to and 5-11 Years after Recycled Water Irrigation. J. Environ. Qual. 48:17581765.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Wang, L., Qian*, Y.L, Brummer, J., Wilhelm, S., Leach, J. 2019. Biomass Production and Soil Carbon Analysis of Switchgrass under Rainfed or Minimal Irrigation in a Semiarid Environment. Agron J. 111:1704-1711.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Lin, Y. and Qian, Y.L 2019. Mineral Composition of Kentucky Bluegrass under Recycled Water Irrigation on Golf Courses. HortScience 54:357361.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: 4. SUN T.?Z.Q. JIA?Y.L.QIAN?H.J. LIU?J.n.TANG. 2019. Comparison on Functions of Wind-Break and Sand-Fixation of Nitraria Tangutorun Nebkhas at Different Developmental Stages in Minqin Desert-oasis Transition Zone. J. Yunnan Agri. Univ. 34:713-724.
• Type: Journal Articles Status: Awaiting Publication Year Published: 2020 Citation: 5. Majed D. Alotaibi, Badr H. Alharbi, Mohammed A. Al-Shamsi, Ali A. Al-Namazi, Saif F. Alharbi, Thobayet, S. Alshahrani, and Y.L. Qian. 2019. Assessing the Response of Five Tree Species Toward Air Pollution. J Environ Manag. (Tentatively accepted)
• Type: Other Status: Published Year Published: 2019 Citation: Qian, Yaling and Lin, Yuhung. 2019. Relationships of soil analysis, turf quality and shoot analysis of Kentucky bluegrass under effluent water irrigation on golf courses. Golf Course Management. June. 87(6):73-74.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Yaling Qian and Sarah Wilhelm. 2019. Compost topdressing reduces necrotic ringspot incidence, decreases thatch, and improves turf quality in Kentucky bluegrass lawns. ASA, CSSA and SSSA International Annual Meetings. 2019, p. 118386.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Josh Lambright and Yaling Qian. 2019. Water Use and Drought Tolerance of 35 Cool-Season Turfgrass Cultivars. ASA, CSSA and SSSA International Annual Meetings. 2019, p. 118265.

Progress 10/01/17 to 09/30/18

Outputs
Target Audience:PLANT SCIENTISTS, AGRONOMISTS, WATER AND SOIL SCIENTISTS, LANDSCAPE MANAGERS, GOLF COURSE MANAGERS, RESEARCHERS, AND URBAN PLANNERS, Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Provided research opportunities for both graduate and undergraduate students. How have the results been disseminated to communities of interest? Provided presentations to turfgrass foundation and green industry professionals. Provided report to the golf course industry. Provided online industry reports. Published in a book titled 'arid environments and sustainability' and other relevant journals. What do you plan to do during the next reporting period to accomplish the goals?In 2019, we will: a) continue a project started in 2017 for selecting water saving Kentucky bluegrass and tall fescue for Colorado turf industry. The goal of the project is to determine relative drought resistance and document water quantity required to maintain acceptable and desirable turf quality for 34 Kentucky bluegrass and tall fescue; b) will continue to evaluate and select elite saltgrass lines from breeding cycles; c) Evaluate methane and nitrous oxide emissions on golf courses under different fertilizer treatments; and d) evaluate effects of salinity and water logging on different species of turfgrass. Salinity and waterlogging are two common problems associated effluent water irrigation on landscape sites. ?

Impacts
What was accomplished under these goals? Water Reuse: In 2018, an experiment was completed on eight golf courses in a semiarid region, including three courses with recycled water irrigation for 10 years, three courses with recycled water irrigation for 18 - 26 years, and two courses with surface water for irrigation for 15 and 18 years. Turf quality of Kentucky bluegrass (Poa pratensis) (KBG), the most widely used turfgrass species in the United States, was evaluated on 25 roughs from the above-mentioned golf courses. Concurrently, KBG shoot samples and soil samples from these sites were collected. Shoots of KBG were analyzed for mineral concentration including Na, Ca, Mg, K, Cl, B, S, P, Mn, Fe, Zn, Cu, and Mo. Electrical conductivity (EC) and sodium absorption ratio (SAR) of soil saturated paste were determined. Recycled water irrigation for 10 and >18 years increased clipping Na by 4.3 and 9.9 times and Cl by 1.5 and 1.3 times, respectively. Compared to surface water irrigation, B concentration in KBG shoots increased by 3.5 times and K concentration reduced by 16% in the pioneer recycled water irrigation group. Soil SAR in 0-20 cm depth was highly associated with KBG shoot Na as documented by a logarithmic regression of R2=0.70. Based on stepwise regression analyses, Na accumulation in KBG shoots was the major factor leading to negative influences on turf quality. Additionally, soil SAR in the pioneer group was higher than that of the 10-year group. Soil from the surface water irrigation site had the lowest average SAR value. A lower turf quality was associated with higher Na concentration in the shoots and higher SAR in the topsoil (0-20 cm) under recycled water irrigation. Based on our findings, shoot Na concentration is the best predictive variable to explain turf quality under recycled water irrigation in this study. Therefore, it is reasonable to suggest that water treatment and management practices that can reduce soil SAR and KBG Na concentration in the shoots would improve turf quality and plant health under recycled water irrigation. Saltgrass selection and development project continued. In 2018 two lines with different turf characteristics were selected for further evaluation as vegetative cultivars. Several lines with adequate commercial seed production yields have been established . Mini-rhizotron images indicated that root growth in container-grown saltgrass showed increased flushes of fine root growth in response to moderate levels of salinity (8 dS/m) compared to the control. Field-grown saltgrass plots of varying stand age (1, 4, 5, and 8 years) demonstrated that saltgrass root mass was greater with increasing stand age. Additionally, a switchgrass field experiment was conducted in semiarid Colorado to determine: 1) aboveground biomass production of 6 upland switchgrass cultivars, and 2) soil organic carbon content of 2 switchgrass cultivars grown on a marginally saline soil under rainfed and minimal irrigation conditions. In this study, switchgrass grew well on marginally saline soil with limited irrigation. The southern-origin cultivars had greater biomass yields than the northern cultivars.Irrigation increased above and below ground biomass, but not soil C and N content. Two productive switchgrass cultivars sequestered C into the soilat the rates of 1.07-1.36 Mg C ha-1yr-1.

Publications

• Type: Book Chapters Status: Published Year Published: 2018 Citation: Hanan Isweiri and Yaling Qian. 2018. Long-Term Effects of Effluent Water Irrigation on Soil Chemical Properties of Sand-Based Putting Greens. In H. Arman and I. Yuksel (eds). Arid Environments and Sustainability. Pp. 77-92. Intechopen, London, UK. ISBN 978-1-78923-154-0,
• Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Qian, Yaling; Lin, Yuhung. 2018. Comparison of Soil Chemical Properties PRIOR to and 5-11 YEARS after Recycled Water Irrigation. ASA, CSSA and SSSA International Annual Meetings. p. 111013.
• Type: Websites Status: Published Year Published: 2017 Citation: Qian, Yaling; Koski, Tony. 2017. Turfgrass and Environmental Research Program: 2017 Research Summaries. p. 95-98. Development and release of turf-type saltgrass variety.
• Type: Journal Articles Status: Awaiting Publication Year Published: 2018 Citation: Yuhung Lin and Yaling Qian. 2019. MINERAL COMPOSITION OF KENTUCKY BLUEGRASS UNDER RECYCLED WATER IRRIGATION ON GOLF COURSES. HortScience (in Press).
• Type: Journal Articles Status: Accepted Year Published: 2019 Citation: Limei Wang, Yaling Qian, Joe E. Brummer, Sarah Wilhelm, and Jan E. Leach. 2019. Biomass Production and Soil Carbon Analysis of Switchgrass under Rainfed or Minimal Irrigation in a Semiarid Environment. Agron J. (accepted)

Progress 10/01/16 to 09/30/17

Outputs
Target Audience:Green industry professionals, landscape industry professionals, water specialists, golf course managers, water conservation specialists, city planners Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Provided research opportunities for graduate and undergraduate students. Hosted industry visits to the field plots. How have the results been disseminated to communities of interest?Wrote articles for the landscape and golf course industries and other relevant trade publications to provide landscape management professionals with information on the impacts and relative tolerance of landscape plants to recycled water and graywater for irrigation. Privided presentations to US golf association, turfgrass industry professionals, seed companies, etc. What do you plan to do during the next reporting period to accomplish the goals?Continue to address objectives outlined in the proposal. In 2018, we will: a) Start a project on selecting water saving Kentucky bluegrass and tall fescue for Colorado turf industry. The goal of the project is to determine relative drought resistance and document water quantity required to maintain acceptable and desirable turf quality for 34 Kentucky bluegrass and tall fescue; b) Evaluate and select elite saltgrass lines from previous breeding cycles; c) Evaluate methane and nitrous oxide emissions on golf courses under different fertilizer treatments; and d) Evaluate effects of salinity and water logging on different species of turfgrass. Salinity and waterlogging are two common problems associated effluent water irrigation on landscape sites. Great effort will be placed on disseminating research findings to turf managers, landscape managers, water managers, and water treatment specialists.

Impacts
What was accomplished under these goals? The increase of the world's population and the decrease of fresh water resources have led to increased use of alternative water resources to meet the water need. Using treated wastewater (effluent water) for urban landscape irrigation has become a common practice to alleviate fresh water shortage. Golf courses are the leading urban landscape users of effluent water, because intensively managed turf can use nutrients in the wastewater efficiently. In 2017, we completed a study to assess changes in soil chemical properties of sand-based putting greens following conversion from fresh water irrigation to effluent water irrigation, and identify potential concerns related to long-term use of effluent water on sand-based greens. Soil samples were collected and analyzed from 9 out of 18 (1, 3, 5, 7, 9, 11, 13, 15, 17) putting greens on a golf course. The course started to use effluent water for irrigation in 2000. Soil samples (0 -10 cm below soil surface) were collected in September of 1999, 2003 and 2009. Soil test data showed that the soil's chemical characteristics changed over time. Soil organic matter increased from 0.12% to 1.5% and cation exchange capacity increased by as much as double over nine years. Extracted phosphates increased by 388% after nine years of effluent water use. Exchangeable calcium, magnesium, potassium, and sodium also increased, by 198%, 16%, 148%, and 452%, respectively, over nine years of effluent water irrigation. In addition, increases over time were found for extractable iron, manganese, copper, zinc, and aluminum. In conclusion, using effluent water for irrigation has both benefits and risks. Increased salinity (EC) and sodium levels are the greatest risks when using effluent water; however, to a certain degree, these can be managed through appropriate cultural practices such as leaching and adding gypsum. Supplemental nutrients and decreased fertilizer costs are the greatest benefits of using effluent water for irrigation. Our results showed that released nitrogen, phosphorus, potassium, and magnesium levels increased in the soil after using effluent water, which would be beneficial for the grass and lowering the fertilizer's cost. In addition, we found the trace elements such as Cu, Zn, and Mn in effluent water were beneficial for the grass on sand based putting greens. This is a new finding associated with sand-based root zone. Inland saltgrass is indigenous to western North America, it is adapted to specific niches of alkaline and saline soils. The planting of saltgrass on roughs and possibly even on fairways could help golf courses conserve potable water because of its tolerance to lesser quality water (reclaimed or saline waters) while maintaining acceptable turf quality and providing a playing surface. Inland saltgrass has value for use as turfgrass and/or a revegetation plant in areas that commonly have high soil salinity levels. In 2017, three pairs of males and females were selected and increased to 1000 plugs each. These materials were transported to a turfgrass seed company for on-site evaluation of seed production via a material transfer agreement. We expect that the evaluation of seed production of these fields can be achieved in 2020.

Publications

• Type: Journal Articles Status: Published Year Published: 2017 Citation: Yuhung Lin and Yaling Qian. 2017. Mineral composition of Kentucky bluegrass under effluent water irrigation. Cutting Edge. Golf Course Management. October. 85:77.
• Type: Book Chapters Status: Awaiting Publication Year Published: 2018 Citation: Hanan Isweiri and Yaling Qian. 2018. Impacts and sustainability of long-term effluent water irrigation on soil properties of putting greens. In Arid Environments and Sustainability. ISBN 978-953-51-5659-8.
• Type: Theses/Dissertations Status: Published Year Published: 2017 Citation: Hanan Isweiri. 2017. The Effects of Effluent Water Irrigation and Salinity on Soil Chemical Properties and Three Species of Perennial Grass. Ph.D. Dissertation. Colorado State University, Fort Collins
• Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Yaling Qian, Tess Additon, Dana K. Christensen, Sarah Wilhelm, Mohamed Shahba and Anthony J. Koski. 2017. Development of Turf-Type Saltgrass. ASA, CSSA and SSSA International Annual Meetings. p. 107628.

Progress 07/01/16 to 09/30/16

Outputs
Target Audience:Turfgrass managers, water specialists Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Provide research opportunities for graduate students How have the results been disseminated to communities of interest?Provided presentations to green industry professionals; Provided report to local water providers about the long term impact of recycled water irrigation on landscape plants and soils. Provided scientific presentation the ASA, CSSA and SSSA International Annual Meetings. What do you plan to do during the next reporting period to accomplish the goals?Continue studies to address objectives outlined in the proposal: 1. To evaluate effects of irrigation with different reuse waters on soil and plants, and evaluate different options for minimizing the negative effects of irrigation with reuse waters; 2. To select elite saltgrass lines that salty environments; 3. To determine the greenhouse gas (GHG) budgets and further to select practices that reduce carbon footprint in urban turfgrass systems; and 4. To disseminate research findings.

Impacts
What was accomplished under these goals? Recycled water irrigation is taking place at landscape sites such as public parks, golf courses, and school playgrounds. Research information is needed to better understand the long-term effects of recycled water irrigation on urban landscapes. Therefore, research is in progress to: 1) assess changes in soil chemical properties after different years of recycled water irrigation, 2) evaluate landscape plants and turfgrass grown on golf courses irrigated with recycled water, and 3) determine the relationship of landscape plant health index to shoot mineral concentrations and soil chemical properties. There is limited research on turf-atmospheric exchanges of trace gases, especially those that address the impact of management practices unique to golf courses. Different sections of a course, such as fairways and roughs, employ different management practices. Research has been conducted to: 1) quantify N2O emissions from a Colorado golf course fairway and rough using three urea fertilizers that utilize different mechanisms to control the release of N substrate, and 2) determine seasonal effects of N2O emissions from fairway and rough following fertilization at different times of the year. In this study, fertilizer treatments consisting of urea with inhibitors of nitrification and urease (INU), polymer coated urea (PCU), and uncoated balanced methylene urea chain (BMU), which utilize different mechanisms to control the release of N substrate, were applied to a golf course fairway and rough three times during the growing season at a rate of 50 kg N ha-1 per application. The vented chamber method was used to measure turf-soil-atmospheric N2O exchange. Cumulative emissions from fairway INU, PCU, and BMU treatments totaled 6.5, 1.9, and 7.6 kg N2O-N ha-1 yr-1, representing a 4.02, 1.25 and 4.75% loss of total N applied, respectively. Fertilizer treatments applied to the rough had cumulative emissions of 2.4, 1.50, and 1.49 kg N2O-N ha-1yr-1 from INU, PCU, and BMU treatments, corresponding to a 1.21, 0.62, and 0.61% loss of total N applied, respectively. The lower N2O emission on roughs was likely associated with greater carbon pools, lower soil moisture and temperatures. This study demonstrated that, on a cool-season turfgrass fairway, summer N fertilization (coupled with low mowing height) can lead to great and episodic N2O fluxes. Therefore, avoiding summer application of fertilizers that release inorganic nitrogen quickly can reduce emissions of N2O in fairway management. Nitrogen fertilizer type, fertilizer application timing, mowing practice, soil temperature and soil water fill pore space were all observed to have significant effects on N2O emissions. This study supports the effectiveness of using PCU fertilizer in reducing N2O emission from cool-season turfgrass fairways when soil conditions favor denitrification during warm periods. Applying INU and BMU materials when soil is cool and dry was effective in moderating N2O losses. Therefore caution in avoiding soil conditions that favor denitrification is advised to reduce N2O losses, especially on highly managed fairway. The taller mowing height and the thatch layer on the rough further reduced N2O emissions by cooling surface temperatures, but these effects were more significant for INU and BMU fertilizers than for PCU.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: Katrina Gillette, Yaling Qian*, Ron Follett, Steve Delgraso. 2016. Nitrous oxide emissions from a golf course fairway and rough after application of different nitrogen fertilizers. J. Environ. Quality. 45:1788-1795.
• Type: Theses/Dissertations Status: Published Year Published: 2016 Citation: 3. Yuhung Lin. 2016. Comparison of soil properties and Kentucky bluegrass shoots mineral composition prior to and after 10-11 years irrigation with recycled water. MS Thesis. Colorado State University, Fort Collins
• Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Lin, Yuhung; Qian, Yaling. 2016. Mineral composition of Kentucky bluegrass under effluent water irrigation. ASA, CSSA and SSSA International Annual Meetings. p. 102489.
• Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Yaling Qian and Yuhung Lin. 2016. Soil Properties and Mineral Composition of Turfgrass Prior to and after 10 Yrs of Irrigation with Effluent Water. ASA, CSSA and SSSA International Annual Meetings. p. 100163