1. Integrating Precision Mobile Drip and Variable Rate Irrigation Technologies for Specialty Crop Vegetable Production

Background: Today, approximately 4.5 million acres of cropland in the Texas High Plains, mostly planted to cotton or corn, are irrigated using 30,000+ center pivot systems. Due to increasing groundwater scarcity and increased pumping costs, growers are looking for ways to maintain and improve their operations’ profitability, including switching to growing high-value crops such as watermelon, cantaloupe, tomatoes, and peppers. Center pivot sprinkler irrigation, however, can negatively impact specialty crop quality; using drip irrigation is preferable. This project is exploring the potential of converting existing irrigation infrastructure to mobile drip and targeting water applications dynamically throughout the growing season.

Lead Researcher: Charles Rush, TX A&AM University
Partners: Texas A&M University, USDA-ARS Bushland, Dragon Line, Valmont, and Dynamax Inc.

Abstract: In this project, Texas A&M AgriLife, in collaboration with USDA-ARS and additional industry partners, is integrating and testing the use of Mobile Drip Irrigation (MDI) and the Irrigation Scheduling and Supervisory Control and Data Acquisition (ISSCADA) plant/soil water feedback system to produce high-quality vegetables for fresh market sales in the Texas Panhandle region. This integrated system will be compared against conventional center pivot irrigation with low elevation sprinkler application (LESA) and traditional surface drip (DI), to evaluate crop yield and quality, water use and water use efficiency, and total economic return. 

2. Improving Irrigation Scheduling by Combining Data on Soil Water Supply and Atmospheric Evaporative Demand

Background: According to the last two decades of USDA farm and ranch irrigation surveys, just a modest percentage (~15% or less) of U.S. producers rely on technology like soil or plant sensors or irrigation schedulers to decide when to irrigate. Meanwhile, remote sensing data is often too complex or opaque to support producers in making real-time irrigation decisions. This project is testing a new irrigation scheduling algorithm (Supply-Demand Dynamics (SDD)) that combines cutting-edge remote sensing data, proximal sensing data, and in-situ sensor data to compare how its recommendations pan out compared to traditional irrigation scheduling methods/practices.

Lead Researcher: Trenton Franz, University of Nebraska-Lincoln
Partners: UNL, University of Illinois at Urbana-Champaign, Aspiring Universe Corporation, Arable Labs, HydroInnova LLC, Corteva, and PlanetLabs Inc.

Abstract: The project will evaluate the water use efficiency (yield based on applied irrigation) of irrigation decisions that guided by the new “Supply-Demand Dynamics” (SDD) algorithm compared to other common irrigation practices (rainfed as a baseline, Management Allowable Depletion (MAD), farm manager, and checkbook irrigation) at two study sites in Nebraska. Remote sensing, proximal sensing, and in-situ sensors will be used to calibrate and validate the SDD algorithm and ground truth local water and energy budgets.

The SDD algorithm is based on the Ecosys model. It can be implemented using just real-time, remote sensing weather or crop products as well as by combining remote sensing data with local crop and weather station data from a variety of vendors. This flexibility makes the algorithm scalable, deployable, and cost-effective, offering a high value proposition to many industries, local, state and federal government entities, and non-governmental organizations. As part of its work on this project the team will develop Application Programming Interfaces (API) to improve the interoperability and usability of this algorithm with other data products, including local crop and weather station data, ideally hitting the sweet spot that will make the benefit and process of using technology to target and time water use clearer and more straightforward for producers.

3. Quantifying Irrigation Water Savings from Multiple Agrivoltaics Configurations

Background: “Agrivoltaics” integrates two separate activities: agriculture and electricity produced using ground-mounted solar photovoltaic (PV) technologies. Solar projects can take up large areas of land, and under certain configurations, particularly when solar panels are elevated, agricultural activities can take place around and under the panels. This team will characterize irrigation water requirements and potential irrigation savings in Agrivoltaic systems by evaluating the impacts of different panel heights on microclimate and soil conditions, how different vegetation types (with different root structures and water requirements) affect irrigation needs, and how irrigation requirements differ underneath and around solar panels. 

Photo: Jack’s Solar Garden

Lead Researcher: Jordan Macknick, National Renewable Energy Lab
Partners: Jack’s Solar Garden, NREL, University of Arizona, Colorado State University

Abstract: Agrivoltaics has the potential to provide partial shade throughout the day, thereby reducing irrigation water needs, which can be particularly important in semi-arid environments. Prior work by the team in Tucson, Arizona, showed the partial shade of the solar panels led to a doubling of yield while requiring 30% less water than an open-air adjacent plot. Moreover, as the efficiency and generation of PV panels is dependent upon temperature, the cooler microclimate created underneath the PV panels from vegetation led to a ~2% increase in annual solar output, when compared to an adjacent PV installation that had non-vegetated groundcover. This IIC-supported research will explore how these findings might translate to Agrivoltaics systems in Colorado.

The team is testing the hypotheses that Agrivoltaic systems will 1) require less irrigation water and 2) use water more efficiently for crop production in Colorado, with work taking place at Jack’s Solar Garden, a 5-acre Agrivoltaic solar installation near Longmont, Colorado that is the largest research-oriented facility of its kind in the U.S.

4. Closing the Loop on Sustainable Plasticulture

Background: Just for the U.S., the irrigation industry annually manufactures approximately 250 million pounds of plastic drip tubes, tapes, and emitter lines. Some of these products will be actively used in fields or landscapes for a long time (10-30 years), while other products, such as thin walled drip tapes, are only used for one crop growing cycle (4 months). Only a small percentage of these products are recycled, and much of the un-recycled and even some “recycled” plastic drip products ends up in landfills or other non-renewable waste streams. This project is exploring a closed-loop approach to re-manfacturing single-use dripline into thickwalled dripline, a potentially valuable proposition for the irrigation industry as it strives to produce products and support production systems more sustainably.

Photo: Jain Irrigation, Inc.

Lead Researcher: Charles Hillyer, California State University, Fresno
Partners: Fresno State, Jain Irrigation, and DOW Chemical

This project has two parts. First, the team will conduct an economic feasibility study of utilizing recycled plastics from drip irrigation that will consider: 

  • Main cost drivers affecting recylability: Power requirements, capital expenses, water treatment, and transportation 
  • Operational scale: Exploring how recycling may be more viable if undertaken in-house or via a centralized or decentralized service 
  • Freight & Logistics: Process and cost of maintaining this material stream. 

Second, the project team will conduct physical testing and performance in the lab as well as in the field of thick-walled drip tubing manufactured from recycled plastic to study to characterize its quality. Tests will be conducted in compliance with ASABE standard S435.1, including: burst pressure, emitter uniformity, emitter discharge rates, head loss, and plugging susceptibility. 

5. Precision Irrigation on Golf Course Fairways Using Soil Moisture Sensor and Mapping Technologies

Background: The golf course industry is under increasing pressure to reduce management inputs, especially irrigation. Fairways account for an average of 28 irrigated acres on each of the 15,000+ golf courses in the United States. Annual median water use per acre of these areas is between approximately 250,000 and 1,250,000 gallons, depending on the region (Golf Course Superintendents Association of America, 2015). Currently, the use of soil moisture sensing and mapping technologies for precision irrigation of turf for golf courses is minimal.

Image: Examples of hand-drawn sketch maps of golf course superintendent’s perceived wettest and driest areas within fairways versus interpolated soil moisture maps from soil moisture data collected from the same fairway (Straw et al., 2020).

Lead Researcher: Chase Straw, TX A&M University
Partners: Texas A&M, University of Minnesota, The Toro Company, United States Golf Association

Abstract: Research that helps to demonstrate the potential for water and energy savings through precision irrigation of fairways could entice more superintendents to schedule irrigation using soil moisture sensors and their mapping features. This project expands a project originally initiated in Minnesota to involve 6-8 additional golf courses in the warmer setting of southeast TX that have fairways of hybrid bermudagrass (Cynodon dactylon(L.) Pers. x C. transvaalensis Burtt-Davy).

The team will compare golf course fairway water consumption in Minnesota and Texas using a precision irrigation approach and conventional irrigation scheduling methods. In addition, this project will survey golf course superintendents nationwide to better understand their current irrigation practice and driving forces/barriers to their adoption of precision irrigation technologies.

6. Connecting Field Performance to Watershed Health: the Added Power of Sharing Data (project expanded/extended from 2020)

Background: The partners in this project are engaged in collaboration with the Twin Platte Natural Resources District and 5 local public power districts to enlist growers’ participation in establishing a big-data system that collects hourly irrigation well electrical use for the purpose of providing real-time estimates of water delivery at farm-level and watershed scales. This project aims to provide irrigators and watershed managers accurate knowledge of real-time water use to support optimal data-based management decisions.  

Lead Researcher: Dayle McDermitt, Nebraska Water Balance Alliance (NEWBA)
Partners: NEWBA, UNL, Grower Information Services Cooperative (GiSC), and Olsson

Abstract: This project builds on an initial IIC investment in 2020 to establish observation wells with aquifer water level sensors and digital flow meters and go beyond the preliminary results from data collected that year.  are reported here. The team is: (1) testing the hypothesis that electrical run time informed by electrical power consumption of a pressure-regulated center pivot can be used along with annual flow-test results to estimate water delivery throughout a growing season, even with variable end gun use and other variables; (2) evaluating if electrical power consumption per unit water delivered can be related to changes in aquifer level over the growing season; (3) integrating measured water delivery from a population of center pivot irrigation wells with changes in aquifer level using groundwater models in the Groundwater Evaluation Toolbox; and (4) communicating the results of this research to irrigators and water managers to support more efficient use and management of water resources.  

Image credit: NEWBA. Well irrigation pattern from a well being used in this study. Gaps in the blue outer ring indicate when/where the end gun is off. 

7. Towards Pivot Automation with Proximal Sensing for Maize and Soybean in the Great Plains (project extension/expansion from 2020)

Background: More producers might use scientific irrigation scheduling to manage irrigation if it was automated and reliable. This project is developing an approach to automate center pivot irrigation, incorporating multiple types of sensors to reduce the uncertainty associated with recommendations for when and how much to irrigate. 

Image (credit Derek Heeren): Top view and side view of pivot mounted sensors. A) Schematic of top view showing last four spans. B) Side view shown through image from the field site. 

Lead Researcher: Derek Heeren, University of Nebraska-Lincoln
Partners: UNL, USDA-ARS Bushland, Valmont

Abstract: This project has four objectives: 1) evaluating the accuracy of pivot-mounted multispectral (MS) and Infrared Thermometer (IRT) sensors compared to data from stationary sensors and sensors deployed using unmanned aircraft; 2) comparing crop health in terms of vegetative indices and crop water stress for maize and soybean in relation with varying levels of soil water content; 3) developing thresholds using thermal indices for triggering irrigation for the sub-humid climate of the eastern Great Plains; and 4) comparing total applied irrigation and crop yield by comparing the performance of an existing patented system (ISSCADA) involving center pivot automation and pivot-mounted sensors against traditional irrigation scheduling methods. 

8. Agriculture and Landscape Irrigation Industry Research Needs Survey and Assessment

Lead Researcher: Inge Bisconer, consultant working with the Irrigation Association
Partners: Irrigation Innovation Consortium, Irrigation Association, Colorado State University

Background: The Irrigation Innovation Consortium (IIC) is partnering with the Irrigation Association to conduct interviews and survey a wide range of irrigation industry stakeholders. The purpose of this inquiry is to better understand and characterize which collaborative research areas are most important to the industry in terms of the development and adoption of water and energy efficient irrigation technologies.