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Drip Irrigation Guide A Case Study at Berggren Demonstration Farm
By the University of Oregon’s Environmental Leadership Program Sustainable Farms Team:
Ashleigh Angel, Alex Burgdorfer, Maddie Cheek, Brady Chiongbian, Will Dickerson, Wilson Hui, Zoe Lavier, Rena Nenot and Emma Porricolo
Table of Contents
1. Introduction to Drip Irrigation (pg. 2)
2. Oregon Water Law (pg. 2-3)
3. Varying Methods of Drip Irrigation: A Case Study of Berggren Farm (pg. 4)
4. Calculating Energy and Water Needs for Your System (pg. 4-5)
5. Pump Calculations and Introduction to Variable Frequency Drives (pg. 5-6)
6. Drip Irrigation Design and Costs (pg. 6-9)
7. Paying for Your Drip Irrigation Project (pg. 9-11)
8. Conclusion (pg. 11-12)
9. Acknowledgments (pg. 12-13)
Figures Table 1: Contact information for various resources we used in designing the drip system for BDF. Figure 1: DripWorks drip tape estimator calculates flow rate (GPH) for specific drip irrigation systems depending upon numbers of beds, drip tape lines, and row length. Table 2: Detailed graph of the cost of all the materials needed for drip irrigation system. Figure 2: Drip irrigation plan with specified crops and materials needed, generated on Dripworks Garden Planner.
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1. Introduction to Drip Irrigation
Recent climate conditions have negatively influenced agricultural production due to increased droughts throughout the United States. In 2015, an estimated 82% of the state of California experienced an ‘extreme drought’, resulting in $1.5 billion of drought related farm-loss and 17,000 agricultural jobs lost statewide . Furthermore, warming weather has 1
severely limited snowpack percentages in Oregon - in 2015 Oregon received a concerning 6% of average snowpack levels . Consequently, the governor of Oregon declared 15 counties as 2
drought stricken. As climate change continues to impact the quantity and quality of water it will be vital for agricultural farmers to adapt to the environmental conditions and adopt more effective water management practices. Drip-irrigation is considered a Best Management Practice (BMP) because of its ability to efficiently and economically irrigate agricultural crops. The process of drip-irrigation allows water to be applied directly to the base of the plant through a matrix of tubes and valves and then slowly filter through the root structure, thereby minimizing the total quantity of water needed in order to effectively irrigate the plants. This ‘more crop per drop’ method is a useful water management practice because it is more likely to provide sufficient irrigation for agricultural fields in comparison to other irrigation practices during times of reduced water availability, such is the case in many parts of California. In certain instances, drip irrigation has reduced water consumption by an impressive 70% in comparison to other irrigation practices, such as flood irrigation . 3
According to the University of Rhode Island, the following bullet points demonstrate the various benefits of the Best Management Practice- drip irrigation.
Benefits of drip irrigation:
● Prevents disease by minimizing water contact with the leaves, stems, and fruit of plants ● Allows the rows between plants to remain dry, improving access and reducing weed
growth ● Saves time, money, and water because the system is so efficient ● Decreases labor ● Increases effectiveness on uneven ground ● Reduces leaching of water and nutrients below the root zone 4
2. Oregon Water Law
It is important to consider what kind of access rights you have to your water resource
before planning a drip irrigation system. Your access rights will impact your ability to install a drip irrigation system and may affect the availability of cost-share and other funding. Water rights in Oregon are regulated by Oregon’s water laws. ‘Water Rights In Oregon; An Introduction To Oregon’s water laws’, or Aqua Book, is a document available on the website
1 http://www.bloomberg.com/news/articles/2014-08-11/california-drought-transforms-global-food-market
2 http://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/home/?cid=nrcs142p2_046169
3. http://www.rainbird.com/documents/corporate/iuow/iuow_whitepapers.pdf- “Rain Bird”
4 http://www.uri.edu/ce/healthylandscapes/dripirrigation.htm - ‘Drip Irrigation for the Home Garden.’
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Oregon.gov. It summarizes laws regulating water in the state of Oregon and provides four bases for water use:
- Water may be used only for beneficial purpose without waste. - The oldest water right holder takes the priority over the new rights holder water supply in
case of shortage. - A water right is attached to the land where it is established; if the land is sold, the water
right goes with the land to the new owner. - A water right must be used at least once every five years to remain valid.
Water rights principle in Oregon
● Under Oregon’s water code, all water is publicly owned. Therefore, individuals need a
permit to use it, even when the water passes through their property. ● Water rights in Oregon function according to the Prior Appropriation Doctrine
established February 24, 1909. This doctrine states that the first person to obtain water rights has the priority of usage above the junior water rights holder, and so on for the next oldest until all water rights are satisfied or until there is no more water available. This means in case of droughts the older water rights holders takes priority over the youngest ones. This contrasts with the Riparian doctrine, usually applied on the East Coast, where landowners have a right over the water flowing through their land.
Acquiring, transferring and ending terminating or relinquishing water rights
There are three steps in the process of obtaining water rights:
1. Applying to the Water Resources Department (WRD) for a permit to use water. 2. Once the permit is granted, the applicant must construct a water system and start using
water. 3. The permit holder must hire a certified water rights examiner to complete a survey of
water use and submit a report about how and where water is being used to the WRD. If use is in compliance with the provision of the permit, a water right certificate will be issued based on the report. Water rights are restricted to the conditions, place of diversion, and type of use, described
in the report written by the water rights examiner. To transfer a water right, the holder must file a transfer application with the WRD to change one or more of the conditions of its right. For the transfer to be granted, the WRD needs to be sure it will not affect the water rights of others.
A water right remains valid as long as it is used without a lapse of five or more consecutive years. If unused for five years or more, the water right is considered forfeited and is subject to cancellation. Cancellation requires a legal process to determine if the period of non-use occurred unless 15 years have passed since the period of non-use. Once cancelled, the landowner must apply for new water rights through the usual process.
Applying for water rights or affirming your rights are still valid is an important part of deciding your next step to implement a drip irrigation system.
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3. Varying Methods of Drip Irrigation: A Case Study of Berggren Farm
An effective drip irrigation system on a farm is tailored to the constraints and needs of the climate, soil type, and the farm’s production crops. The first step in designing a drip irrigation system is determining which drip tape (high, medium, or low flow) has the emission rates that will best suit the soil type. Information on the soil and climate type can be found online at the USDA Web Soil Survey. 5
Berggren Demonstration Farm Case Study: Berggren lower field: #95 soil ‘Newberg fine sandy loam’
· Mean annual precipitation: 40-60 inches · Frost-free period: 165 to 210 days
· Landform: flood plains · Farmland classification: prime farmland
These are the conditions for the production field at Berggren Demonstration Farm (BDF), a 30-acre farm outside of Walterville, Oregon. You can use the considerations for this site-specific study to assess your own needs and constraints regarding implementing a drip irrigation system.
4. Calculating Energy and Water Needs for Your System
When designing a drip irrigation system, energy and water conservation are usually the first considerations. Our team initially set out to utilize gravitational force to power our system through an elevated water tank located above Berggren’s vegetable garden, but the local geography proved incapable of fulfilling the system’s pressure requirements. This led to a full reconsideration of our system design, as our new system required an optimized pump able to supply correct pressure and flow directly to the drip lines.
Calculating the necessary flow and pressure within the drip system itself can be done easily with simple algebra. DripWorks, an irrigation supply company, has readily available calculators on their website ( http://www.dripworks.com/category/calculators ) that allow for quick, accurate measurements. If you already have a pump, use DripWorks’ flow estimator calculator to understand the flow available for your system. If you will later optimize a pump for the system you design, go directly to their drip tape estimator to compute the flow rate and zoning requirements. Once the system’s requirements are calculated, a pump must be optimized to fulfill these needs. An existing pump may be retrofitted using a variable frequency drive, discussed in more detail in Section 5, but designing the system prior to purchasing a pump is highly recommended. You will first need to understand the most suitable pump type for your water resource.
Many options – such as end-suction centrifugal, submersible, turbine, booster, and jet pumps - exist that are best-suited for varying conditions exist. While calculating optimal pump specifications is possible prior to purchasing a new pump, variance between pump manufacturers may lead to miscalculations in practice as two pumps with the exact same horsepower may have widely varying flows and pressures. It is best to contact a local pump dealer who will be able to
5USDA Web Soil Survey: http://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm
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discuss the many options available. Pacific Ag Systems Inc. is a great resource for Oregonian farmers, and other options exist nationally such as Sprinkler Warehouse . 6
Table 1: Contact information for various resources we used in designing the drip system for BDF.
Categories Organization Phone/E-mail Website
General drip system guidance and calculators
Dripworks (800) 522 3747
www.dripworks.com
Local organization specializing in drip system design and installation
Pacific Ag Systems Inc. (541) 998 1983
www.pacag.com/
Irrigation Supplies Sprinkler Warehouse (281) 500 9800 www.sprinklerwarehouse.com
Government resource for general conservation practices
National Resource Conservation Service (Lane County District Conservationist Tom
Burnham)
(541) 465 6443
www.nrcs.usda.gov/
Water rights WaterMaster (541) 382 3620 www.oregon.gov/OWRD/pages/index.aspx
Soil maps and data from the National Cooperative Soil Survey
Web Soil Survey (Portland State Office)
(503) 414 3261 www.websoilsurvey.sc.egov.usda.gov
5. Pump Calculations and Introduction to Variable Frequency Drives
This section will provide information on how to determine a pump to fit in the system.
We also provide a brief cost comparison on Variable Frequency Drives (VFD) and a fixed speed motor for a year.
After designing the system, the next step will be to determine which pump will fit into your drip irrigation system. You will need to find out the flow rate you need for the drip tapes. For example, 40 Gallon Per Hour (GPH) is needed for every 100 feet of drip tape at a pressure of 8 pressure per inch (PSI) for high flow t-tape (GPH varies by the type of drip tape). Given a field 125 ft. in length, the necessary flow rate is calculated as follows: 40 GPH/100 feet x 12,500 feet of tape = 5,000 GPH.
Therefore, the maximum flow rate of the pump should be more than 5000 GPH.
6 http://www.sprinklerwarehouse.com
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Relationship between pressure (PSI), flow rate and horsepower : 7
● Pressure (PSI) = Force (lbs) / Unit Area (square inch) ● Flow Rate (GPH) = Volume (gallons) / Unit Time (hour) ● Horsepower = [Pressure (psi) x Flow rate (GPH)] / 1714
In order to retrofit an existing pump to optimally supply the necessary pressure and flow rate for a
planned irrigation system, a VFD may be used in order to adjust power delivery to the pump’s motor. If you already own a pump, this may be cheaper than buying a new pump. Moreover, according to Baldor Electric Company, VFD control technology allows only 22% of the horsepower to operate a pump at 60% speed compare to a fixed speed pump . Here is an example calculation of potential cost saving.First, 8
determine the kilowatt usage and the energy cost: ● Kilowatts = Horsepower (Hp) x 0.746 kWh/hp x 1/ System Efficiency ● Energy Cost=Kilowatts x hours/year x cost($)/ Kilowatts hour (kWh)
Combine the equations to compare the cost between a fixed motor pump and VFD-run motor pump : 9
Fixed Speed Motor: (100 HP) x (1/95% eff.) x (.746 kW/Hp) x ($0.08/kWh) x (12 hrs/day) x (365 day/year) = $27,516 per year VFD Run Motor: (100 HP) x (0.22) x (1/95% eff.) x (.746 kW/Hp) x ($0.08/kWh) x (12 hrs/day) x (365 day/year) = $6,053 per year Cost Analysis of purchasing VFD vs. a fixed-speed pump
If BDF purchases a new pump, we recommend Munro LP200B 2 HP 50 PSI Centrifugal Pump which cost $582 . If BDF chooses to retrofit an existing pump, the ideal VFD will depend on the existing 10
pump’s horsepower. For BDF’s 20hp pump, we recommend a low cost GK3000-4T0150G 20 hp (15kW) VFD, 3 Phase 220V, 380V, 460V VFD, that cost around $700 , it would be able to control the flow rate 11
and more efficient on electricity and water usage. 6. Drip Irrigation Design and Costs
Designing a drip irrigation system requires various parts, each of which has a specific
function, to ensure maximum efficiency from the pump to the drip tape. As stated in Section 4, it is best to work backwards when designing a drip irrigation, from the drip tape to the pump. The steps listed below is the process we went through in designing a drip irrigation for lower field crops at BDF.
1) Determine the potential area size and layout. For BDF, we designed a system to irrigate 25 rows with 4 lines of drip tape in each 125-foot-long row. (25 beds) X (125 ft/bed) X (4 lines/bed) = 12,500 ft. of drip tape needed
7 http://web.applied.com/assets/attachments/779D4407-D2AE-6FAA-7DA1CEDE2268977B.pdf
8 http://www.sustainableplant.com/assets/Baldor/Baldor-0411-Pump-Energy-Savings-with-VFDs.pdf
9 http://www.sustainableplant.com/assets/Baldor/Baldor-0411-Pump-Energy-Savings-with-VFDs.pdf
10 http://www.sprinklerwarehouse.com/Munro-Centrifugal-Pump-p/lp200b.htm
11 http://www.gohz.com/20hp-vfd
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2) Determine which kind of drip tape is required based on specific soil type and climate: high, medium, or low flow (see Section 2 of the guide for more information on how to determine this). At Berggren we chose high flow drip tape because the soil drains quickly; therefore, high flow is necessary to keep moisture in the soil. Additionally, the frequency of drip holes or how often you run the system varies by crop. Not all crops prefer direct irrigation from drip tape.
3) Design the irrigation system with the proper flow rates and pressure. Pressure regulators can be used to ensure the proper pressure to drip tape groupings.The drip irrigation supply retailer, DripWorks, has a great tool to calculate flow rate depending on amount of drip tape.
Figure 1: DripWorks drip tape estimator calculates flow rate (GPH) for specific drip irrigation systems depending upon numbers of beds, drip tape lines, and row length. 12
4) Determine what filter you need based upon the sediment in your water source. Filters are vital to drip irrigation systems as they prevent clogs in the drip tape that can impede a system’s ability to operate effectively. Types of filters will vary by water source. Currently at Berggren, a large filter on the submersible pump filters out large sediment. We recommend placing a disk filter at the beginning of the drip irrigation system attached to the mainline to filter small organic matter. We also recommend adding additional inline filters in each of the five sub-sections.
5) Determine if you need an automatic timer system. Although we are not including an automatic timer system in our drip system for BDF, it can help to increase the system’s efficiency. Even with wholesale price, the price range is from about $29.95 to $79.95, it is an expensive addition.
12 http://www.dripworks.com/category/calculator-drip-tape-revised
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6) Make sure that you have all the small pieces to tie the system together, including: hold downs, tubing ends, elbows, and tape row starts. Drip irrigation supply providers can often help you design drip irrigation system catered
to your farm with their products. As a case study from Berggren Demonstration Farm, we have compiled an approximate pricing from DripWorks. The following prices are based on wholesale prices from DripWorks. The chart below is a detailed list of the costs for just the irrigation system and pump, cost for the K-line tubing to attach the pump to the mainline are not included. Table 2: Detailed graph of the cost of all the materials needed for drip irrigation system.
Drip Irrigation Parts Description
Item Number Number Cost Per Unit
Filter Arkal Disc Filter, 200 Mesh, 1" FA1200 1 $57.95
Pressure Regulator Senninger 1” Limit Valve- 30 PR1LV30 1 $17.95
Female Hose Start 3/4" Easy Loc) Female Hose Start 6 6 x $2.29 = $13.74
Mainline Tubing - 1 inch 1" Polytubing, 250' roll F1250 100 ft = 1 roll $79.95
Mainline ends 1" Easy Loc End Cap ELMC1 1 $1.59 Subline tubing - ¾ inch ¾" Polytubing, 100’ 34100 100 ft = 1 roll $17.95 Subline end ¾" Figure 8 ending CF834 5 5 x $0.34 = $1.70
Tape Row Start LSB 4 tapes/bed x 25 beds=
100 100 x = $0.46 =$46 Section inline filters FI120 5 $ 4.29
Drip tape (T-Tape) 8mil/8" space high flow, 7500 feet roll 2 rolls 2 x $188 = $376
Tape coupler LSC $0.64
Valves 3/4" Easy Loc x 3/4" MPT w/ Valve - EL34MPV34 5 5 x $1.95 = $9.75
Elbows 3/4" Easy Loc Elbow ELL34 55 5 x $ 2.49 = $12.45 Hold downs U-shaped Wire (Packs of 100) SUHD-100 3 packs 3 x $ 8 = $24 T-Tape ends LSGS 25 25 x $0.49 = $12.25
Pump 2 HP 50 PSI Centrifugal Pump Munro
LP200B 1 $664.13
TOTAL COST $1,339.70 This example budget does not include the additional cost for K-line piping. K-line piping is required to connect the pump from the water source to the main filter
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Figure 2: Drip irrigation plan with specified crops and materials needed, generated on Dripworks Garden Planner. 13
7. Paying for Your Drip Irrigation Project
Sustainable agricultural practices and technologies are often criticized as being too expensive to be implemented on small farms. The prices of these practices vary depending on the size of the farm and the types of practices chosen. However, there are many government and business resources that are designed to support small farms interested in investing in organic certification and sustainable agricultural practices. The organizations offer grants and easements to aid small farmers interested in sustainable agriculture.
13 http://gardenplanner.dripworks.com/
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Grants and cost-shares are other options for funding sustainable agriculture projects. Grants are often offered by governmental agencies such as the USDA 13 or by local, national, and international organizations. There are five different types of grants in sustainable agriculture: research and education, professional development programs, farmer/rancher grants, professional and producer grants, and graduate student grants. Examples of these grants can be found on the Western Sustainable Agriculture Research and Education website13.
A financial easement for sustainable agriculture is, “a non-possessory right to use another’s property” . The Natural Resource Conservation Service (NRCS) offers an agricultural 14
easement program that provides technical assistance to farmers to conserve land used for agriculture in addition to surrounding ecosystems. The agricultural land easement includes conservation programs that preserve grasslands, rangelands, pasturelands, and shrublands. Easements can provide significant public benefits such as improved environmental quality, wildlife conservation areas, open space protection, and historic area preservation. These easements provide incentives for farmers such as tax deductions 14. The wetland easement program provides financial and technical aid for landowners and farmers to help restore, and protect wetlands. There are several subcategories of wetland reserve easements: permanent, 30-year, term, and 30-year contracts.
Every year BDF applies for multiple grants in order to fund various projects. Money received from grants has been used to fund projects such as installation of a solar energy system. Money awarded through grants can be used for a variety of projects, including drip irrigation.
Finding Funding Opportunities
Many grants through government agencies can be found online at grants.gov, where one can search by category of different agencies, eligibility, type of grant, etc. NRCS also offers financial assistance and general support for farmers. For more information about what funding opportunities are available to your organization or location, you can call the NRCS office for more information, or go online.
Grants are also commonly offered by companies, donors, and nonprofits. The Sustainable Agriculture Research and Education organization has many grants to help fund sustainable 15
agricultural projects. Grants can also be found through online grant-search databases such as grantwatch.com or grantforward.com. These search engines include grants from a wide variety of funders.
When searching for grants, make sure you meet the eligibility requirements before applying. You can do this by checking the requirements online or calling the funder. Often these grants have funding goals associated with water conservation, resource management, watershed protection, etc. Below is a descriptive list of a few grants that could potentially be used to fund a drip irrigation system.
14 http://financial-dictionary.thefreedictionary.com/easement 14 http://www.sare.org/Grants 15http://www.landtrustalliance.org/what-you-can-do/conserve-your-land/benefits-landowners 15
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1. Conservation Innovation Grant (CIG) -Natural Resource Conservation Service (NRCS). Nationally, funding for this grant program is up to 20 million dollars and organizations in all 50 states are eligible to apply. The grant funds conservation projects and sustainable initiatives in the private sector of agricultural production. Applying for this grant includes a pre-proposal screening in addition to the grant application and must be mailed to the NRCS. The grant is offered annually through the 2014 Farm Bill.
2. Water Conservation, Reuse and Storage Program - Offered through the Oregon Water
Resources Department. This grant program requires organizations to have initial funding which the grant program would then match. The program requires farmers and organizations to conduct energy and resource analysis of how the proposed project would help to conserve water and benefit others from minimal water usage. The grant is offered annually and its application information can be found online . 16
3. The Fruit Guys Community Fund- The Fruit Guys is a non-governmental organization
dedicating to help fund small farmers implement sustainable agricultural products. Partnered with Community Initiatives, the Fruit Guys Community Fund provides grant opportunities for small farmers with $30,000 available for funding multiple projects. In the past this grant has been awarded to farmers implementing drip irrigation systems. The grant is offered annually. More information can be found online . 17
Through researching what type of grants you are eligible for, you can find many creative ways to help finance your drip irrigation project. With many options for funding available, conserving water and energy through drip irrigation is more accessible than ever before.
8. Conclusion
A well-designed drip irrigation system can help to reduce the energy and water expenditures that accompany irrigating produce fields. By reducing energy and water inputs on farms, farmers are able to enjoy financial savings, as well as decrease their resource footprint.
The process of designing and implementing a drip irrigation system can be lengthy and complicated, but the process is easier with a little background research, planning, and assistance. A good starting point for taking on a project like this is to know your local climate, soil type, and water rights. Planning the crop layout of your field or garden is another good preliminary step to take, as some crops may have different watering requirements than others, and you’ll want to be able to plan for those. Next, you’ll want to get in touch with an irrigation vendor, like DripWorks, who can provide a variety of resources to help you plan your system, including their website, a catalogue, and a representative that can talk you through the process. Once you’ve determined the setup of the drip system, you’ll want to contact a pump dealer to find the correct pump, with the right pressure and flow rate, to fit your system’s needs.
16 http://www.oregon.gov/owrd/Pages/LAW/conservation_reuse_storage_grant_program.aspx
“Water Conservation Grant” 17
http://fruitguys.com/about-us/fruit-guys-community-fund “Fruit Guys Community Fund”
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We recognize that the step-by-step process we have outlined is not always realistic. Many small farmers face economic constraints which require them to work with the equipment they already have. Luckily, there are ways to work around these barriers: a little creativity, some research into funding, and handy gadgets - like the variable frequency drive (VFD) - can go a long way. Systems can be retrofitted and tweaked in order to meet the needs of the individual farmer, and farmers can utilize grant and cost-share options in order to receive funding to implement a sustainable practices project.
Our learning and service outcomes included engaging in sustainable farming practices and designing a drip irrigation system for Berggren Demonstration Farm’s lower vegetable production field. We learned about sustainable farming practices (such as rotational grazing and improving native pollinator habitat on site) by participating in them in order to gain a better understanding of what those practices entail and how they differ from conventional methods. Additionally, we worked through the process of planning a drip irrigation system. This process required physical measurements, online research, and communication with various people and companies that acted as resources for pulling this project together.
Through our research, we hope to provide a clear and concise information source for other small farmers looking into installing a drip irrigation system.
9. Acknowledgements
We would like to thank the Berggren Demonstration Farm staff, the leaders of the Environmental Leadership Program, and the Berggren affiliates. - Angela Andre is the farm manager for this organization. She has 30 years of experience in best farming practices and education in natural resources. We would like to thank her for her knowledge and wisdom on best farming practices on an ecologically-conscious farm. - Jared Pruch is the program coordinator for Berggren. He has experience with nonprofit management, program development, environmental education, and best practices within agriculture. We would like to thank him for his advice on grant-writing and sustainable farming during our term. - Peg Boulay is the co-director of the Environmental Leadership Program at the University of Oregon. We would like to thank her for making this opportunity and connection for our team possible. - Deion Jones is a master’s student in Environmental Studies and a Graduate Teaching Fellow at the University of Oregon. We would like to thank him for his contribution, leadership, and support throughout this program. Additionally we would like to thank: Jim Russell - Whitewater Ranch Anthony Knox - Pacific Ag. Systems Tom Burnham and Kevin Macquoid - Natural Resources Conservation Service
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Harper Keeler, Dan Schuler, and Keegan Caughlin - University of Oregon Urban Farm This project was funded in part by the Environmental Leadership Program’s small gift fund.
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