Brief Summary of Minutes of Annual Meeting

• The annual meeting was held on December 3, 2018, in the S-7 (Seaside level) room of Long Beach Convention & Entertainment Center in Long Beach, California. The meeting was presided by 2018 Committee Chair Dr. Rhuanito Ferrarezi.
• The venue chosen for the next meeting in 2019 was San Antonio, Texas at ASA, CSSA, and SSSA Annual Meetings on Nov 10-13, 2019. Dr. Steve Evett and Dr. Freddie Lamm will provide support with the society to not have registration fees.
• Amir Haghverdi, Assistant CE Specialist at the University of California Riverside, was elected 2019 secretary for the W3128 group. Dr. Davie Kadyampakeni and Dr. Ripendra Awal become 2019 Committee Chair and Vice-Chair, respectively.
• W3128 Project will expire on September 30, 2019. The new proposal is due in the National Information Management Support System (NIMSS) system by January 15, 2019.
• Bradley Rein (NIFA – USDA) provided NIFA updates. He briefly discussed on the background of new NIFA director Dr. J. Scott Angle and his interest in agricultural production. Dr. Rein also highlighted transition plans (building relocation, personnel challenges) of NIFA briefly. Dr. Rein informed the committee about some funding opportunities: AFRI Water for Food Production Systems (about seven awards), Sustainable Agricultural Systems, Agriculture Systems and Technology (Foundational and Applied Science Program).
• Steve Evett provided ARS updates and state reports were presented by Dr. Ripendra Awal (Texas) and Dr. Amir Haghverdi (California).
• The rest of the meeting was focused on new W4128 grant discussion and writing. All participants were able to contribute in an online document created by Dr. Rhuanito Ferrarezi for proposal writing.
• The committee organized Special Session – W3128: USDA-National Institute of Food & Agriculture Multistate Microirrigation Research Group on December 4 (2:00 p.m.-5:00 p.m.). The session was moderated by Dr. Danny H. Rogers, Oklahoma State University. Following eight papers were presented during the session:
  • Evaporative Loss Differences Between Subsurface Drip Irrigation & Sprinkler Irrigation – Southern High Plains Experience  - Steven R. Evett, USDA-ARS
  • Direct Root Zone Drip Irrigation to Enhance Precision Deficit Irrigation - Pete Jacoby, Washington State University
  • Subsurface Drip Fertigation for Site-specific Precision Management of Cotton - Mark Dougherty, Auburn University
  • Soil Moisture & Nutrient Dynamics in Root Zone of Collard Greens Produced in Different Organic Amendments & Rates - Ripendra Awal, Prairie View A&M University
  • Potential for Intensification of Maize Production With Subsurface Drip Irrigation - Freddie Ray Lamm, Kansas State University
  • Citrus Water Use & Soil Moisture Distribution Using Regulation Deficit Irrigation - Davie Mayeso Kadyampakeni, University of Florida
  • Effect of Irrigation Methods & Plant Densities on Grapefruit Cultivated in Open Hydroponics System - Rhuanito Soranz Ferrarezi, University of Florida Institute of Food and Agriculture Sciences Indian River Research and Education Center
  • Creation & Adoption of Smart Agriculture Innovations - Clinton C. Shock, Oregon State University Malheur Experiment Station

Alabama

Objective 1. Develop robust and appropriately-scaled methods of irrigation scheduling using one or more soil-, plant- or weather-based approaches.

Ongoing development of a method to use field soil tension monitoring in soybeans to develop crop coefficients for irrigation scheduling.

Objective 2. Develop microirrigation designs and management practices that can be appropriately scaled to site-specific characteristics and end-user capabilities and

Objective 3. Develop technology transfer products for a diversity of stakeholders to promote adoption of microirrigation.

Compiled seven years of subsurface fertigated cotton yield data in replicated research plot study. Treatments related to timing of fertigated nitrogen. Results presented in 2018 Irrigation Association meeting and being revised for publication 2019.

California

University of California Riverside (Department of Environmental Sciences)

1. Outputs

Research findings were disseminated via refereed journal publications, conference proceedings, and a number of presentations at national and international meetings (see the publication section below). HYDRUS models have been updated with several new capabilities and options that have been developed for various research projects, which in turn have been published in peer-reviewed journals.

2. Activities
   In 2018, we offered two- or three-day short courses on how to use HYDRUS models at a) Czech University of Life Sciences, Prague, Czech Republic, b) Colorado School of Mines, Golden, CO, c) the Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Beijing, Peoples Republic of China, d) Tokyo University of Agriculture and Technology, Department of Ecoregion Science, Tokyo, Japan, e) WASCAL Headquarters, Accra, Ghana, NC. About 150 students participated in these short courses.

Meetings attended:

1. W-3188 Western Regional Soil Physics Group Meeting, Desert Research Institute, Las Vegas, NV, January 2-4, 2018.
2. CZO/LTER/NEON/ISMC Workshop "Using Observation Networks to Advance Earth System Understanding: State of the Art, Data-Model Integration, and Frontiers",February 13-15, 2018.
3. 6th International Conference "HYDRUS Software Applications to Subsurface Flow and Contaminant Transport Problems", University of Tokyo, Tokyo, Japan, September 20, 2018.
4. ISMC (International Soil Modelling Consortium) bi-annual meeting in Wageningen, The Netherlands, November 5-7, 2018.

HYDRUS Teaching:

1. A short course “Advanced modeling of water flow and contaminant transport in porous media using the HYDRUS software packages” organized by Czech University of Life Sciences, Prague, Faculty of Agrobiology, Food and Natural Resource, Prague, Czech Republic, March 19-21, 2018. Other instructor: M. Th. van Genuchten (20 participants).
2. A short course “Modeling Water Flow and Contaminant Transport in Soils and Groundwater Using the HYDRUS Computer Software Packages”, Colorado School of Mines, Golden, CO, June 25-27, 2018. Sole instructor (14 participants).
3. A short course “Modeling Water Flow and Contaminant Transport in Porous Media Using the HYDRUS and HP1 Software Packages”, Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Beijing, Peoples Republic of China, July 2-4, 2018. Sole instructor (28 participants).
4. A short course “Modeling Water Flow and Contaminant Transport in Soils and Groundwater Using the HYDRUS Computer Software Packages”, Tokyo University of Agriculture and Technology, Department of Ecoregion Science, Tokyo, Japan, September 18-19, 2018. Other instructors: Dr. Hirotaka Saito (60 participants).
5. A short course “Hackathon: Modeling of Irrigation, Water Flow and Nutrient Transport in Soils (using the HYDRUS Software Packages)”, WASCAL Headquarters, Accra, Ghana, November 29-30, 2018. Other instructor: Dr. Roland Baatz (30 participants).

3. Short-term Outcomes and Milestones

Objective 1. Develop robust and appropriately-scaled methods of irrigation scheduling using one or more soil-, plant- or weather-based approaches.

Objective 2. Develop microirrigation designs and management practices that can be appropriately scaled to site-specific characteristics and end-user capabilities.

We continue to expand the capabilities of the HYDRUS modeling environment by developing specialized modules for more complex applications that cannot be solved using its standard versions. The standard versions of HYDRUS, as well as its specialized modules, have been used by myself, my students, and my collaborators in multiple applications described below.

1. The Use of Hydrus Models to Evaluate Various Irrigation and Fertigation Problems - Agricultural Applications
2. Karandish et al. (2018) applied HYDRUS (2D/3D) for predicting the influence of subsurface drainage on soil water dynamics in a rainfed-canola cropping system. The simulation results demonstrated that the groundwater table management can be an effective strategy to sustain shallow aquifers in the subsurface-drained paddy fields during winter cropping.
3. Darzi-Naftchali et al. (2018) applied the HYDRUS (2D/3D) model to investigate the combined effects of different subsurface drainage systems and water management strategies on water balance, groundwater table, transpiration efficiency, and water use efficiency in paddy fields.
4. Hartmann et al. (2018) developed a root growth model and implemented it into HYDRUS. The model considers root growth to be a function of different environmental stresses. The effects of temperature in the root growth module was the first part of the newly developed HYDRUS add-on to be validated by comparing modeling results with measured rooting depths in an aeroponic experimental system with bell pepper.
5. Karimov et al. (2018) used HYDRUS-1D to evaluate whether a change in cropping pattern can produce water savings and social gains. The analysis was carried out for the Fergana Valley, Central Asia. Modeling results indicate that replacing alfalfa with winter wheat in the Fergana Valley released significant water resources, mainly by reducing productive crop transpiration when abandoning alfalfa in favor of alternative cropping systems. However, the winter wheat/fallow cropping system caused high evaporation losses from fallow land after harvesting of winter wheat. Double cropping (i.e., the cultivation of green gram as a short duration summer crop after winter wheat harvesting) reduced evaporation losses, enhanced crop output and hence food security, while generating water savings that make more water available for other productive uses.
6. Shelia et al. (2018) implemented the HYDRUS flow routines into the DSSAT crop modeling system. DSSAT refers to a suite of field‐scale, process‐based crop models that simulate the phenological development of crops, including detailed information about various yield components, from emergence till maturity on the basis of crop genetic properties, environmental conditions (soil, weather) and management options. While the DSSAT system thus far relied on the “tipping bucket” water balance approach to represent soil hydrologic and water redistribution processes, implementation of the HYDRUS flow routines into DSSAT allows one to use now the more process-based Richards equation to represent these processes.
7. Phogat et al. (2018a) evaluated soil water and salinity dynamics under sprinkler irrigated almond exposed to a varied salinity stress at different growth stages using both field experiments as well as their analysis using HYDRUS (2D/3D). This study provided a greater understanding of soil water and salinity dynamics under almond irrigated with waters of varying qualities.
8. Phogat et al. (2018b) used the HYDRUS-1D model to identify the future water and salinity risks to irrigated viticulture in the Murray-Darling Basin, South Australia. Water and water related salinity risks to viticulture were assessed by running the HYDRUS-1D model with 100 ensembles of downscaled daily meteorological data obtained from the Global Climate Model (GCM) for 2020– The modeling output was evaluated for seasonal irrigation requirements of viticulture, root zone soil salinity at the beginning of the new season, and the average seasonal salinity for all 100 realizations for four 20-year periods. The modeling results indicate that soil salinity at the beginning of the vine season and the average seasonal salinity are crucial factors that may need special management to sustain the viticulture in this region.
9. Kacimov et al. (2018) revisited the Kornev’s irrigation technology and Kidder’s free boundary problems using analytical solutions and verified them using HYDRUS.
10. Brunetti et al. (2018) developed a hybrid Finite Volume – Finite Element (FV-FE) model that describes the coupled surface subsurface flow processes occurring during furrow irrigation and fertigation. The numerical approach combines a one-dimensional description of water flow and solute transport in an open channel with a two-dimensional description of water flow and solute transport in a subsurface soil domain, thus reducing the dimensionality of the problem and the computational cost. The modeling framework includes the widely used hydrological model, HYDRUS, which can simulate the movement of water and solutes, as well as root water and nutrient uptake in variably-saturated soils. The robustness of the proposed model was examined and confirmed by mesh and time step sensitivity analyses. The model was theoretically validated by comparison with simulations conducted with the well-established model WinSRFR and experimentally validated by comparison with field-measured data from a furrow fertigation experiment conducted in the US.
11. Liu et al. (2019) developed a coupled model a numerical model simulating water flow and solute transport for a furrow irrigation system, in which surface water flow and solute transport are described using the zero-inertia equation and the average cross-sectional convection-dispersion equation, respectively, while the two-dimensional Richards equation and the convection-dispersion equation are used to simulate water flow and solute transport in soils, respectively. Solutions are computed numerically using finite differences for surface water flow and finite volumes for solute transports in furrow. Subsurface water flow and solute transport equations are solved using the CHAIN_2D code. An iterative method is used to couple computations of surface and subsurface processes. The coupled model was validated by comparing its simulation results with measured data.
12. Karandish and Šimůnek (2018) used the field-calibrated and validated HYDRUS (2D/3D) model to find optimal management scenarios based on the concept of the water footprint (WF), a measure of the consumptive and degradative water use. The scenarios were defined as a combination of different salinity rates (SR), irrigation level s (IL, the ratio of an actual irrigation water depth and a full irrigation water depth), nitrogen fertilization rates (NR), and two water-saving irrigation strategies, deficit irrigation (DI) and partial root-zone drying (PRD).
13. Wongkaew et al. (2018) used an artificial capillary barrier (CB), which consisted of two layers of gravel and coarse sand, to improve the soil water retention capacity of the root zone of sandy soil for the cultivation of Japanese spinach. The performance of a CB under specific conditions was evaluated using numerical simulations. Wangkaew et al. (2018) (i) evaluated the performance of a CB during the cultivation of Japanese spinach irrigated at different rates and (ii) investigated the effect of the irrigation schedule on root water uptake. Numerical analysis was performed using HYDRUS-1D after the soil hydraulic properties of the CB materials were determined.
14. Saefuddin et al. (2018) evaluated a ring-shaped emitter made from a standard rubber hose that has been developed and introduced for subsurface irrigation in Indonesia. It is a low-cost irrigation technology based on indigenous materials and skills. To build a ring-shaped emitter of the original design, a rubber hose is bent into a ring shape with a diameter of about 20 cm, and then five 5-mm holes are drilled into it at even intervals. The entire ring-shaped hose is covered with a permeable textile so that water can infiltrate in all directions around the buried emitter. The main objectives of this study thus were 1) to experimentally investigate the water movement around a buried ring-shaped emitter and 2) to numerically evaluate the effect of modifying the design of the ring-shaped emitter on soil water dynamics around the emitter. Numerical simulations were carried out using HYDRUS, one of the most complete packages for simulating variably-saturated water flow in two- or three-dimensional domains.
15. Karandish and Šimůnek (2019) applied the HYDRUS (2D/3D) and SALTMED models to investigate the influence of various water-saving irrigation strategies on maize water footprints. The models were first calibrated and validated based on data collected in a two-year field investigation under five water-saving irrigation treatments: full irrigation, partial root-zone drying at water deficit levels of 55% and 75%, and deficit irrigation at the same levels. While the SALTMED model performed well when simulating crop growth parameters, the HYDRUS (2D/3D) model was more accurate when simulating soil water and solute transport.

1. Hydrological Applications
2. Szymkiewicz et al. (2018) simultaneously used the HYDRUS and SWI2 packages for MODFLOW to simulate freshwater lens recharge and the position of the salt/freshwater interface. While the HYDRUS package gives MODFLOW the capability to consider processes in the vadose zone, the SWI2 package is used to represents in a simplified way variable-density flow associated with saltwater intrusion in coastal aquifers.
3. Beegum et al. (2018, 2019) first updated the HYDRUS package for MODFLOW (HPM) by developing a new methodology to eliminate the error in the determination of the recharge flux at the bottom of the HPM profile and then additionally also implemented solute transport into the HPM. She then successfully tested these two new developments against fully two- or three-dimensional simulations with HYDRUS (2D/3D).
4. Sasidharan et al. (2018a) conducted numerical and field scale experiments to improve our understanding and ability to characterize the drywell behavior. HYDRUS (2D/3D) was modified to simulate transient head boundary conditions for the complex geometry of the Maxwell Type IV drywell. Falling-head infiltration experiments were conducted on drywells located at the National Training Center in Fort Irwin, California (CA) and a commercial complex in Torrance, CA to determine in situ soil hydraulic properties by inverse parameter optimization.
5. Brunetti et al. (2018a) investigated the use of different global sensitivity analysis techniques in conjunction with a mechanistic model in the numerical analysis of a permeable pavement installed at the University of Calabria. The Morris method and the variance-based E-FAST procedure were applied to investigate the influence of soil hydraulic parameters on the pavement’s behavior. The analysis revealed that the Morris method represents a reliable computationally cheap alternative to variance-based procedures for screening important factors and provides the first inspection of the model. The study was completed by a combined GSA-GLUE uncertainty analysis used to evaluate the model accuracy.
6. Brunetti et al. (2018b) assessed the information content of aboveground fast-neutron counts to estimate SHPs using both a synthetic modeling study and actual experimental data from the Rollesbroich catchment in Germany. For this, the forward neutron operator COSMIC was externally coupled with the hydrological model HYDRUS-1D. The coupled model was combined with the Affine Invariant Ensemble Sampler to calculate the posterior distributions of effective soil hydraulic parameters as well as the model-predictive uncertainty for different synthetic and experimental scenarios. Measured water contents at different depths and cosmic-ray neutron fluxes were used to assess estimated SHPs.

• Fate and Transport of Various Substances (Carbon Nanotubes, Viruses, Explosives)

With another member of the W3188 group, Scott Bradford we worked on three aspects of the transport of pathogens in the subsurface.

1. Arthur et al. (2018) used the HYDRUS-1D model that was modified to consider particle dissolution to evaluate dissolution and transport of energetic constituents from the new insensitive munitions (IM) formulations IMX-101, a mixture of NTO, NQ, and DNAN, and IMX-104, a mixture of NTO, RDX, and DNAN. NTO and DNAN are emerging contaminants associated with the development of insensitive munitions as replacements for traditional munitions. Flow interruption experiments were performed to investigate dissolution kinetics and sorption non-equilibrium between soil and solution phases.
2. Rahmatpour et al. (2018) investigated the transport and retention of polyvinylpyrrolidone (PVP) stabilized silver nanoparticles (AgNPs, diameter of 40 nm) under saturated and unsaturated conditions in intact columns of two calcareous sandy loam (TR) and loam (ZR) soils. The one-site kinetic attachment model in HYDRUS-1D, which accounted for time- and depth-dependent retention, was successfully used to analyze the retention of AgNPs. The results showed that the degree of saturation had little effect on the mobility of AgNPs through undisturbed soil columns. The results suggested the limited transport of AgNPs in neutral/alkaline calcareous soils under both saturated and unsaturated conditions.
3. Adrian et al. (2018) conducted packed column experiments to investigate the transport and blocking behavior of surfactant-and polymer-stabilized engineered silver nanoparticles (Ag-ENPs) in saturated natural aquifer media with varying content of silt and clay fraction, background solution chemistry, and flow velocity. Breakthrough curves for Ag-ENPs exhibited blocking behavior that frequently produced a delay in arrival time in comparison to a conservative tracer that was dependent on the physicochemical conditions, and then a rapid increase in the effluent concentration of Ag-ENPs. This breakthrough behavior was accurately described using one or two irreversible retention sites that accounted for Langmuirian blocking on one site.
4. Sasidharan et al. (2018) investigated the influence of virus type (PRD1 and FX174), temperature (flow at 4 and 20°C), a no-flow storage duration (0, 36, 46, and 70 d), and temperature cycling (flow at 20°C and storage at 4°C) on virus transport and fate in saturated sand-packed columns. The vast majority (84–99.5%) of viruses were irreversibly retained on the sand, even in the presence of deionized water and beef extract at pH = 11. A model that considered advective–dispersive transport, attachment, detachment, solid phase inactivation, and liquid phase inactivation coefficients, and a Langmuirian blocking function provided a good description of the early portion of the breakthrough curve.
5. Liang et al. (2019) investigated the roles of graphene oxide (GO) particle geometry, GO surface orientation, surface roughness, and nanoscale chemical heterogeneity on interaction energies, aggregation, retention, and release of GO in porous media. Calculations revealed that these factors had a large influence on the predicted interaction energy parameters.

1. Reviews
2. Jacques et al. (2018) reviewed recent adaptations of the HPx module of HYDRUS that have significantly increased the flexibility of the software for different environmental and engineering applications. They provide an overview of the most significant changes of HPx, such as coupling transport properties to geochemical state variables, gas diffusion, transport in two and three dimensions, and the support for OpenMP that allows for parallel computing using shared memory. The authors concluded that HPx offers a unique framework to couple spatial-temporal variations in water contents, temperatures, and water fluxes, with dissolved organic matter and CO2 transport, as well as bioturbation processes.
3. Šimůnek et al. (2018) reviewed new features of the version 3 of the HYDRUS (2D/3D) computer software package. These new features include a flexible reservoir boundary condition, expanded root growth features, and many new graphical capabilities of the GUI. Mathematical descriptions of the new features are provided, as well as two examples illustrating applications of the reservoir boundary condition.

Invited Presentations:

• Focus presentation "The use of HYDRUS models to evaluate processes in the critical zone" at the CZO/LTER/NEON/ISMC Workshop "Using Observation Networks to Advance Earth System Understanding: State of the Art, Data-Model Integration, and Frontiers",Bolder, Colorado, February 13, 2018.
• Keynote presentation “Recent Developments and Applications of the HYDRUS Software Packages” at the workshop "HYDRUS Software Applications to Subsurface Flow and Contaminant Transport Problems", University of Mie, Mie, Japan, September 13, 2018.
• Keynote presentation “Recent and Current Developments and Applications of the HYDRUS Software Packages” at 6th International Conference "HYDRUS Software Applications to Subsurface Flow and Contaminant Transport Problems", University of Tokyo, Tokyo, Japan, September 20, 2018.
• Invited presentation “Numerical Modeling of Vadose Zone Processes using HYDRUS and its Specialized Modules”, Meiji University, Tokyo, Japan, September 26, 2018.
• Invited presentation “Numerical Modeling of Vadose Zone Processes using HYDRUS and its Specialized Modules”, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan, September 28, 2018.

2018 Awarded and Active Grants

2015-2020    USDA, ARS, Improved Decision Support for Management of Non-traditional Irrigation, 09/30/2015 - 09/29/2020, PI: J. Šimůnek, $225,000.

2016-2019    ANR Competitive Grants proposal #3741 Optimizing Water Management Practices to Minimize Soil Salinity and Nitrate Leaching in California Irrigated Cropland, PI: L. Wu; CoPIs: K. Bali, D. Haver, B. L. Sanden, and J. Šimůnek, 04/01/2016-03/31/2019, $299,613.

2016-2019    ANR Competitive Grants proposal #3771 Improving nitrate and salinity management strategies for almond grown under micro-irrigation, PI: P. Brown; CoPIs: M. Kandelous, J. Šimůnek, S. Grattan, S. Benes, and B. Sanden, 04/01/2016-03/31/2019, $386,112.

2016-2019    DOD, SERDP, 17 ER02-034 in response to SON Number: ERSON-17-03 Improved Understanding of the Fate and Effects of Insensitive Munitions Constituents; Proposal title "Phototransformation, Sorption, Transport, and Fate of Mixtures of NTO, DNAN, and Traditional Explosives as a Function of Climatic Conditions". A project with Dr. Katerina Dontsova at University of Arizona, Tucson, UCR share is $63,447.

2016-2019    EPA, USDA-ARS, Interagency Agreement for the project: "Research Support for Watershed and Basin Hydrology and Water Quality in the Arid and Semi-arid Southwest, USA", $200,000. UCR PI: Jiri Simunek; other funding goes to USDA-ARS Tucson and USDA-ARS Riverside.

2018-2020    USDA-NIFA, "Elucidating Colloidal Facilitated Phosphorus Migration in Soils: Through X-Ray Computed Tomography and Hydrus Modeling",
Drs. Lamba and Srivastava (Auburn University), Dr. Karthikeyan (University of Wisconsin-Madison), Dr. Jiří Šimůnek (University of California Riverside).  
Total Budget: $500,00; UCR share $70,005.

University of California Riverside (Haghverdi Water Management Group)

1. What was accomplished under the project objectives?

A total of 48 research plots were established at UC ANR SCREC in Irvine, California, and are being prepared for irrigation research trial in 2019. The data collection phase will start from February/March of 2019. The irrigation system was installed in July 2018. Each plot is irrigated by 4 quarter circle (pop-up heads) sprinklers, all four controlled by a common solenoid valve for independent control of each plot. In early August 2018, an Acclima CS3500 smart irrigation controller was installed and all solenoid valves were wired to the controller. In addition, soil moisture sensors (Acclima TDT sensors) were installed at 12 plots and were connected to the irrigation controller for continuous monitoring of soil water status within the turf effective root zone throughout the experiment. The plots were covered with bermudagrass sods in August 2018. Bermudagrass was selected due to its superior resistance to heat, drought, salinity and wear compared to other commonly planted turfgrasses in California. All plots are under full irrigation now for the establishment of turfgrass and we will start the irrigation experiment in early 2019.

1. What opportunities for training and professional development has the project provided?

A two-day workshop was organized in 2018 at UCR consisting of hands-on training, lectures and a field tour. The workshop focused on autonomous urban irrigation management and audience were international visiting students and scholars.

1. How have the results been disseminated to communities of interest?

Our website (ucrwater.com) and twitter account (@ucrwater) were used as the clearinghouse to disseminate the findings of the projects in lay language for a diverse audience. The website had on average multiple hundreds page views per month and the twitter account currently has 107 followers.

1. What do you plan to do during the next reporting period to accomplish these goals?

Next steps of the experiment will be to collect soil samples to analyze soil hydraulic properties and soil salinity in the lab, perform an irrigation uniformity test on the plots, to finish instrumentations of the plots, identify the irrigation treatments and calibrate soil moisture sensors if needed, and collect base line infiltration data using SATURO infiltrometer (METER Group, Inc. USA). In addition, two plots with treatment extremes i.e. full irrigation and the highest deficit will be equipped with additional sensors for continues turf and soil monitoring. Pressure switches and/or flow meters will be utilized to precisely record irrigation runtimes and water application on each plot.

University of California Davis (Plant Sciences Department)

Accomplishments: (Objective 1)

A novel method was developed and published describing the use of the pressure chamber to determine stem water potential (SWP) in dormant trees.  A grape industry funded (AVF) project was started to develop installation and operation protocols for a novel, micro-tensiometer (MT) device developed at Cornell University, to continuously measure SWP in trees and vines.  MT’s were installed in five mature grapevines, as well as one almond and one walnut tree, and some of these installations have shown good agreement with pressure-chamber measured SWP for periods of up to 4 months.  Young almond tree evapotranspiration (ET) and calculated crop coefficient (Kc) was measured lysimetrically for years 1-4, and compared to the ET and Kc predicted from a recently published young peach tree model.  For the first 3 years, measured ET and Kc values were substantially higher (about double) than predicted by the model, and after the first year there was a marked overestimate of the soil component of (E of ET) by the model.  By the 4^th (most recent) year, canopy growth had increased so that an individual tree % shaded area and Kc could not be determined, but the maximum midsummer Kc for both year 3 and 4 (about 1.2) was above the published mature (‘full canopy’) almond Kc (1.15).  These results indicate that the currently accepted values for young tree Kc and ET are substantial underestimates, and also that the mature almond orchard Kc and ET are also underestimates.  A multi-year almond water production function experiment was completed, finding that the yield effects of reduced irrigation have been minimal (reductions of from 5 - 25%, depending on location), despite imposing a relatively wide range of irrigation amounts (from 40-60").  A multi-year study was completed to document the long term effects on tree and root health of winter flood irrigations in almond orchards for the purpose of groundwater recharge.  No negative effects of applying an additional 24" of water during the dormant season (December/January) have been observed.  The 5^th year of an ongoing walnut irrigation test was performed, and demonstrated that plant-based measurements (SWP) could be used to delay the first irrigation in the spring by about 1 month, with no detrimental effects on yield, and evidence was obtained that this practice may improve root health over the long term (years).

Training/Professional development:

Three MS and one PhD students were trained.  Two MS and the PhD student graduated.

Dissemination of results:

Extension presentations to growers and other industry personnel have been made at the annual almond and walnut conferences, in addition to presentations at grower meetings that have been organized by extension farm advisors. 

Plans:

The following industry supported projects will be continued: 1) Almond Winter Water Management, 2) Almond Lysimeter (ET), 3) Walnut Early Season Water Management, 4) Microtensiometer development in grapevine and other woody perennials.  A new SCRI project (“Optimizing Irrigation for Sustainable Production of Almonds, Apples and Grapes“) based on the use of the microtensiometer for plant-based irrigation will be submitted.

University of California Davis (Irrigation and Water Management Research Group)

Objective 1. Develop robust and appropriately-scaled methods of irrigation scheduling using one or more soil-, plant- or weather-based approaches.

Development of a methodology for estimating of almond water status using artificial neural networks

Stem water potential (SWP) is a commonly used method for determining plant water status in tree crops but is labor intensive. To eliminate the necessity for intensive fieldwork, artificial neural networks were designed to predict PWS using easier to measure information such as leaf temperature and microclimatic variables including ambient air temperature, relative humidity, incident radiation, and soil water content (Meyers et al., 2018). To collect these variables, leaf monitors developed by Dhillon et al. (2017) and soil water sensors were installed in an almond orchard. The sensors were interconnected through a wireless mesh network which allowed remote data access. SWP values were taken in the field at midday three times a week during the growing season. The artificial neural networks were trained using the Levenberg-Marquardt algorithm. Compared with multiple linear regression models fitting the same data, the neural networks consistently resulted in better R² values. These results suggest that there is potential for machine learning techniques that use artificial neural networks to model the relationship between environmental conditions and plant water stress, which may be used for predicting acceptable temperature difference from target SWP Microirrigated almond orchards.

iCrop Model –Driven Decision Support

We have developed iCrop a novel web-based decision support tool that provides site-specific irrigation scheduling recommendations to growers to tree, vegetable and forage growers in California grower’s majority of have switched to microirrigation. iCrop uses crop simulation models to integrate the entire farming system including soil (S), weather (E, environment), genetics (G), and crop production practices (M, management; e.g., irrigation and fertility management practices). Preliminary evaluation of iCrop on corn and alfalfa has demonstrated on to improve yields and water productivity through in-season adaptive management of irrigation schedules.

Objective 2. Develop microirrigation designs and management practices that can be appropriately scaled to site-specific characteristics and end-user capabilities.

Precision irrigation management by variety in almonds

A significant number of almond growers in California have shifted from flood to microirrigation. Almond production in California has unique water issues, including the need for post-harvest irrigation and the presence of different almond varieties in the same orchard with shifted growth stages and water needs as a way to establish effective pollination. Traditionally, farmers have set up their microirrigation systems (double drip or micro sprinklers) to irrigate the entire orchard the same and cannot independently irrigate the different almond tree varieties within the same orchard. My research investigated how to precisely and independently irrigate different varieties without interfering with harvest activities and offset growth stages of the different varieties. We retrofitted the drip irrigation system on a commercial orchard with a wireless system that we used to remotely open and close tree rows of different varieties independently. Preliminary results from the 2018 growing season showed significant differences in yield amount three almond varieties (Non-peril, Butte and Aldrich) at the same irrigation level.

Precision fertigation management for processing tomatoes

Processing tomato producers in California are faced with several challenges e.g., constrained water supplies due to droughts and institutional policies like SGMA, and the Irrigated Lands Regulatory Program (regulation of nitrate leaching). To optimize profitability under limited water resources, growers need to enhance resource use efficiency through precision irrigation and fertigation. Over 80% of processing tomatoes growers in California have switched from flood to subsurface drip irrigation. In May of 2018 we established a study on a 5 acre subsurface drip irrigation field with automated fertigation and irrigation control by volume using ultrasonic flow meters and a Netafim irrigation controller. The objective of this study was to evaluate the effect of high frequency low concentration fertigation and the low frequency high concentration fertigation on yield of processing tomatoes. Preliminary results indicate that there were no significant differences between high and low frequency fertigation under full irrigation. However, under limited water, sustained deficit irrigation produced lower yields compared to regulated deficit irrigation but increased fruit quality in terms of soluble solute concentration.

Objective 3. Develop technology transfer products for a diversity of stakeholders to promote adoption of microirrigation.

We have developed the iCrop webapp that growers can use for implementing specific irrigation scheduling for a variety of irrigation systems including microirrigation.

B. What opportunities for training and professional development has the project provided?

I integrated a module in the irrigation systems and water management upper level undergraduate class that I teach at University of California Davis every year. The enrollment during the spring quarter of 2018 was 16 students. The students were introduced to computer aided design of microirrigation systems using the IRRICAD software.

I also trained a group of technocrats from Uzbekistan and Turkmenistan on microirrigation management and shared with them experiences from California.

C. How have the results been disseminated to communities of interest?

We have disseminated our results through journal articles, conference presentations, posters and social media (e.g., UCDIrrigation twitter account).

D. What do you plan to do during the next reporting period to accomplish these goals?

We plan to continue with field experiments on precision irrigation management by variety in almonds, precision fertigation management for processing tomatoes and also continue developing and testing of the iCrop decision support system.

Florida

1. What was accomplished under the project objectives?

Objective 1. Develop robust and appropriately-scaled methods of irrigation scheduling using one or more soil-, plant- or weather-based approaches.

Grapefruit production using different irrigation systems and plant density under open hydroponics

Precise irrigation and fertigation management provide a less-limiting environment to roots while minimizing over irrigation and leaching of nutrients. This concept can improve tree growth in the presence of HLB and help optimize water and nutrient use. Higher tree density can increase fruit yield per area under high HLB pressure. We conducted a study to evaluated the efficiency of open hydroponics on ‘Ray Ruby’ grapefruit production under different irrigation systems and tree density. We tested a combination of rootstocks (Sour orange and US897), tree spacing [standard and high density staggered (HDS)], fertilization (dry granular and fertigation), and irrigation systems (drip and microjet).

Objective 2. Develop microirrigation designs and management practices that can be appropriately scaled to site-specific characteristics and end-user capabilities.

Round orange production using different dry granular fertilizer blends, irrigation systems and plant density

Sweet oranges (Citrus sinensis) are impacted by huanglongbing (HLB), a disease associated with Candidatus Liberibacter asiaticus. The disease is threatening the citrus industry, with devastating effects on fruit production. Higher plant density can increase fruit yield per area under high HLB pressure, maximizing income and extending grove survival until a definite cure is found. This study evaluated the effect of tree planting density, fertilizer type and and irrigation systems on fruit yield and quality. ‘Valencia’ orange on ‘Kuharske’ citrange (C. sinensis × Poncirus trifoliata) trees were planted in Sept/2013 (2,995 trees in 1.61 ha). We tested three treatments: standard tree spacing (3.8×7 m, 357 trees/ha) + dry granular fertilizer + microsprinkler irrigation (one emitter per tree; microsprinkler 50 green nozzle, 16.7 GPH at 20 psi) (Bowsmith, Exeter, CA), high density staggered ([2.7×1.5×0.9 m]×6.1 m, 953 trees/ha) + fertigation + microsprinkler irrigation (one emitter per two trees), and high density staggered + fertigation + drip irrigation (two lines per row; Emitterline 0.58 GPH at 10 psi, 12-inch spacing) (Jain Irrigation), in a complete randomized block design with eight replications.

Improving performance of HLB infected trees and root health under partial root zone drying

The goal of this project is to improve the performance of HLB infected trees, soil and root health under partial root zone drying in a modified hydroponic system under greenhouse conditions. The following are the specific objectives: a)   Investigate the optimum fertilization rate of HLB infected trees; b) Determine canopy development, root density and water use under partial root zone drying in hydroponic systems; c) Compare the performance of biochar and compost in ameliorating soil functions and restoring soil microbial diversity. Three N fertilizer rates include: IFAS recommendation for nonbearing trees (Obreza and Morgan, 2008), 75% of IFAS recommendation and 125% of IFAS recommendation with P and K changed proportionally to N. Each fertilization rate has a soil amendment with 1) biochar, 2) compost, and 3) no amendment (control). Two irrigation rates, 100% evapotranspiration (ET) and 75% ET will be used. This will be a 3 x 3 x 2 factorial experiment replicated 4 times in a randomized complete block design.

Objective 3 Develop technology transfer products for a diversity of stakeholders to promote adoption of microirrigation.

Evaluation of water and nutrient use efficiency

Irrigation systems are designed to maximize crop productivity and optimize uniform water application. The amount of water applied is usually determined by empirical methods, which are based on timers instead of the actual crop requirements. Several technologies have recently been developed looking for alternative methods to improve water management efficiency based on weather and soil sensing methods. One of the most relevant advances are the capacitance sensors, offering a great potential to estimate soil volumetric water content (VWC) and electrical conductivity. We conducted a laboratory study to evaluate the accuracy of data collected from several commercial capacitance sensors and establish a calibration equation for different soil types. Tested treatments were five sandy soils (Pineda, Riviera, Astatula, Candler and Immokalee) divided in two depths (0-30 and 30-60 cm) representing the majority of Florida soils used for citrus production.

Idaho

Objective 1.  Develop robust and appropriately-scaled methods of irrigation scheduling using one or more soil-plant or weather-based approaches.

A web-based water-budget irrigation scheduling program developed by Dr. Troy Peters, WSU, and a soil sensor based approach were again compared in 3 locations on Eastern Idaho farm fields irrigated by center pivot irrigation systems in 2018. At each location, one pivot used a LESA (Low Elevation Sprinkler Application) sprinkler package while the other pivot used the existing Mid-Elevation Sprinkler Application (MESA) system.  Differences in water delivered to the ground resulted in a wider seasonal range of crop root zone soil water content on the Control pivots at all three sites than would normally be observed. Water applied to both the Control and LESA pivots was measured by IDWR-approved flowmeters installed before the 2018 growing season.

Four Decagon 10 HS sensors, tipping bucket rain gage and an AgSense data logger with cell phone transmission, and web-based data storage and retrieval were used under each of 6 malting barley pivots. Previous year’s work with the Ag Sense loggers used Watermark granular matrix sensors.  Although sensor information was generally useful for determining if over-irrigation was occurring, abnormal or “odd” data readings occurred with sufficient frequency to limit sensor effectiveness for anything beyond overall trends and limit grower confidence in the data.  Therefore, the 10HS sensors which worked well in 2017 with Onset data loggers, were used on the AgSense loggers this year.  Data quality and appropriate response to wetting and drying events was good and made the information more credible and usable by the farmers.

The WSU “Irrigation Scheduler Remote” program used irrigator-selected soil and crop parameters, AgriMet daily estimated crop ET, and rainfall, and irrigator-input irrigation data to evaluate root zone available soil water and depth of irrigation water required to re-fill the root zone on a daily basis.

Soil sensors were installed at 4 depths (6, 12, 18, and 24 inches) on each site to serve as a daily soil water comparison measurement.  The AgSense data from the sensors and a tipping bucket rain gage (where available) were transmitted by cell phone link to a website at 30-minute intervals.  This information, formatted in a user-defined fashion, was available from any mobile device (cell phone, laptop, desktop,...) that could connect with the website.  Pre and post-season soil sampling at 6-inch intervals to 5 feet (or rock) depth along with rain gage data provided directly-measured water budget information.

Kansas

Objective 1. Develop robust and appropriately-scaled methods of irrigation scheduling using one or more soil-, plant- or weather-based approaches.

In a two year irrigation scheduling study (2016-2017), measured crop water use (sum of irrigation, precipitation, and the change in ASW) compared well with the weather-based calculation on crop evapotranspiration (ETc). Available soil water (ASW) at planting and harvest varied to a much greater degree than did grain yield (≈13.4 vs. 5.4%) implying that the ASW levels were sufficient to prevent yield reductions. Results from an SDI (subsurface drip irrigation) crop intensification study with corn that was initiated in 2017 were summarized in a paper present at the Irrigation Association technical conference. In this study greater corn grain yield and crop water productivity were obtained through appropriate hybrid selection and through increasing plant density.  Yield was not affected by irrigation levels from 85 to 115% of full irrigation, but water productivity was greatest at the lowest irrigation level (0.85 ET). This study will be continued in 2019.

Objective 2. Develop microirrigation designs and management practices that can be appropriately scaled to site-specific characteristics and end-user capabilities.

Drafting of revisions to several extension publications concerning subsurface drip irrigation (SDI) concerning design, management and maintenance continued in 2018.   Two extension publications were completed with one presenting an overview of how SDI is being implemented in Kansas and the second publication outlining the minimum component requirements for successful systems. A study to examine potassium fertilization with SDI for corn was continued in 2018. Results from two years of a three year study comparing precision mobile drip irrigation (PMDI) with SDI for corn at KSU-NWREC has not shown grain yield or water use differences. A field study examining precision mobile drip irrigation (PMDI) where driplines are attached to a moving center pivot platform initiated in 2015 at the KSU Southwest Research-Extension Center at Garden City, Kansas was continued in 2018. 

Objective 3. Develop technology transfer products for a diversity of stakeholders to promote adoption of microirrigation.

Several presentations were made at the regional Central Plains Irrigation Conference along with two presentations at the annual international meeting of the American Society of Agricultural and Biological Engineers (ASABE) and one presentation at the Irrigation Association (IA) technical conference.

What opportunities for training and professional development has the project provided?

A PhD student at SWREC completed work evaluating irrigation application technologies, specifically looking at potential improvements with precision mobile drip irrigation (PMDI).

How have the results been disseminated to communities of interest??

Results have been presented to lay audiences at KSU field days, at a regional multistate meeting, and at three international conferences. 

What do you plan to do during the next reporting period to accomplish these goals?

Field studies will be continued during the coming year.  Presentations will be offered at regional and international meetings. 

Target audience

Producers ranging from large, technologically savvy operations to small, part-time or hobby farming operations. Technical service providers such as USDA-NRCS working to improve irrigation and salinity management on regional, state and national scales. Community of scientists and extension specialists in Kansas and also regional, national and international colleagues, particularly for those with semi-arid summer precipitation pattern. Water managers and regulators within the state and region. Policymakers at the local (e.g., GMDs and LEMAs), state (e.g., State agencies and legislators) and national (Federal agencies and Congress) levels. Rural and community interests and foundations.

New Mexico

Objective 1. Develop robust and appropriately-scaled methods of irrigation scheduling using one or more soil-, plant- or weather-based approaches.

Development and Evaluation of Soil-Based Irrigation Scheduling: We continued to calibrate the soil moisture content sensor to measure the moisture content, soil temperature, and soil salinity for water, solute and energy transport through soil. We are currently comparing Hydra, 5TE and TEROS 12. These probes are also used to schedule irrigation for the growing Pecan. A new low cost datalogger with wireless transmission capability is developed and tested.

Objective 2. Develop microirrigation designs and management practices that can be appropriately scaled to site-specific characteristics and end-user capabilities.

A field experiment in Brackish Groundwater National Desalination Research Facility is currently underway. We are growing halophytes using brackish groundwater and concentrate and also looking at soil property changes. Similar experiments are underway for Chile and Pecan.

Milestone

A low cost datalogger with wireless capability is developed that can substantially reduce costs of soil water content data collection.

Funding

• USDA Hatch grant
• Nakayama Chair Endowment
• WRRI-BOR Cooperation grants
• BOR S&T grant
• Cochran Grant

Oklahoma

Objective 1. Develop robust and appropriately-scaled methods of irrigation scheduling using one or more soil-, plant- or weather-based approaches.

A multi-state (OK, TX, and KS) project on promoting sensor-based technologies to improve irrigation scheduling was continued during the reporting period. As part of this project, canopy temperature and soil moisture sensors were installed at the Oklahoma Panhandle Research and Extension Center near Goodwell, OK, where corn and sorghum plots receive variable levels of irrigation application using a subsurface drip irrigation (SDI) system. The goal is to investigate how these two different types of irrigation scheduling approaches interact and how they can be utilized in managing SDI systems. In addition, soil moisture probes were installed at six other locations in cooperation with local growers. Sensors were evaluated for their accuracy, sensitivity to irrigation applications, and usefulness in improving irrigation scheduling. One challenge in using sensors for irrigation scheduling under SDI is sensor placement, since water movement is not as uniform as under flood or sprinkler systems. To further investigate this challenge additional sensors were installed at different depths and distances from SDI tapes at one site near Hollis in southwest Oklahoma. Our team is going through data quality control and will soon initiate data analysis. We anticipate additional years and sites are required before any conclusions can be made on best management practices for sensor installation under SDI.

Objective 2. Develop microirrigation designs and management practices that can be appropriately scaled to site-specific characteristics and end-user capabilities.

Nothing to report.

Objective 3. Develop technology transfer products for a diversity of stakeholders to promote adoption of microirrigation.

Dissemination of information on adoption of microirrigation systems and advanced methods of irrigation scheduling was accomplished by presenting at numerous field days, meetings, workshops, and in-service trainings.

Presentations (advisees are underlined):

• Datta S, Taghvaeian S (2018) Performance of soil moisture sensors under field conditions. ASABE Annual International Meeting. Jul. 29-Aug. 1, 2018; Detroit, MI.
• Masasi B, Taghvaeian S, Gowda P, Warren J, Marek G (2018) Simulating soil water content, evapotranspiration and yield of variably irrigated grain sorghum using AquaCrop. ASABE Annual International Meeting. Jul. 29-Aug. 1, 2018; Detroit, MI.
• Taghvaeian S (2018) Sensor technologies for improving agricultural water management. Oklahoma Water Research Advisory Board Meeting. Jul. 18, 2018; Oklahoma City, OK.
• Taghvaeian S, Datta S (2018) Evaluating the performance of soil moisture sensors for irrigation management. World Environmental & Water Resources Congress. Jun. 3-7, 2018; Minneapolis, MN.
• Taghvaeian S (2018) Irrigation studies at Oklahoma State University. Science and Data in Action Panel. The Ogallala Summit. Apr. 9-10, 2018; Garden City, KS.
• Taghvaeian S (2018) Using soil moisture sensors to improve irrigation. Oklahoma Irrigation Conference. Mar. 8, 2018; Weatherford, OK.
• Taghvaeian S (2018) Getting the most from your water: Effective irrigation. Oklahoma Farmers Market Conference and Expo. Feb. 22, 2018; Oklahoma City, OK.
• Taghvaeian S (2018) Soil moisture sensors. High Plains Irrigation Conference. Feb. 7, 2018; Amarillo, TX.
• Taghvaeian S, Datta S, Boman R (2018) Utilizing sensor technologies to evaluate and improve cotton irrigation management. Beltwide Cotton Conference. Jan. 3-5, 2018; San Antonio, TX.
• Datta S, Taghvaeian S, Stivers J, Ochsner T, Moriasi D (2017) Performance evaluation of soil moisture sensors under field conditions. 38^th Annual Oklahoma Governor’s Water Conference & Research Symposium. Oct. 31-Nov. 1, 2017; Norman, OK.
• Masasi B, Taghvaeian S, Gowda P, Warren J, Marek G (2017) Assessment of the AquaCrop model for simulating soil water content, evapotranspiration and yield of grain sorghum. 38^th Annual Oklahoma Governor’s Water Conference & Research Symposium. Oct. 31-Nov. 1, 2017; Norman, OK.

Educational material:

1. Taghvaeian S (2018) Comparing pivot & subsurface drip irrigation. Available at: https://youtu.be/-ANCaJJwUXE

Oregon

Non-Technical Summary

Broad expansion of microirrigation is needed. Unless timely action is taken, it is anticipated that water supply and water quality related crises will affect economies and resources of national and international importance. Microirrigation can reduce the waste of water to a negligible amount and reduce the transport of contaminants to surface water and groundwater. Irrigation events can be fine-tuned to spoon feed water and nutrients just in time to minimize plant water stress. Microirrigation can optimize crop production (more crop per drop) and in many cases, increase the quality of agricultural products. Successful experimental microirrigation results will be scaled up to commercial size through this project. Microirrigation information will be transferred effectively to growers through many venues.

What was accomplished under these goals?

Objective 1. Develop robust and appropriately-scaled methods of irrigation scheduling using one or more soil-, plant- or weather-based approaches.

Potatoes: In 2018 we are carefully compared potato irrigation scheduling based on soil moisture sensors (soil water tension, SWT) with irrigation scheduling based on estimated crop evapotranspiration.  These efforts were completed for two potato varieties grown with both sprinkler and drip irrigation.  All treatment combinations were replicated 6 times. The irrigation scheduling techniques provided similar results.  The potato variety ‘Clearwater Russet” produced 44 tons per acre under drip irrigation using crop evapotranspiration irrigation scheduling.

Vineyards:  Soil-based measurements of soil water tension (SWT) were compared with soil water content, plant water potential, and crop evapotranspiration in drip-irrigated vineyards. The ideal amount and timing (trajectories) of water stress (as measured by soil, plant, or weather data) are being studied for various cultivars, weather patterns, and sites. In Oregon we seek to measure the trajectories of stress. Modification of the stress trajectory holds the promise of better water use efficiency, protection of water quality, optimization of product quality, and the realization of providing a better return on vineyard investment. The approach is to collect and evaluate automated data that is interpreted and provided in real time to growers.

Automation of data collection and delivery. The automated approach to collect SWT data in vineyards (above) was tested on onion, potato, quinoa, tomato, skullcap, and stevia in 2018.

Seed production of native plants In Oregon fixed irrigation schedules are being compared to soil- and weather-based scheduling for seed production from native plants. Plant species required 0 to 200 mm of supplemental irrigation per year to maximize seed yield. For a given species, yield responses to irrigation varied substantially by year. We have determined that accounting for rainfall during and prior to seed production improves the accuracy of estimating the amount of irrigation required.  Species differ in the preceding time interval where precipitation needs to be counted against the irrigation requirement.  In 2018 SWT measurements were also collected in a portion of the seed production plots for comparison.

Objective 2. Develop microirrigation designs and management practices that can be appropriately scaled to site- specific characteristics and end-user capabilities.

Delivery of herbicides. Herbicides were applied through the drip irrigation system in the hopes of achieving better control of yellow nutsedge. Outlook herbicide applied through drip irrigation was successful in helping to control yellow nutsedge.  This work is designed to expand the labeled use of drip-applied Outlook herbicide to control yellow nutsedge.

Delivery of fungicides. Fungicides were applied through the drip system to try to obtain better control of root fungi. Pink root and plate rot were not significant problems in the onion fields used for the trials and the products tested were not beneficial.

Adaptation of drip irrigation for potato production Potato production is generally conducted with sprinkler irrigation. In the US drip irrigation has not been cost effective in comparison to sprinkler irrigation. We sought to change the drip irrigation configuration so that the drip irrigation system could be more efficiently utilized.

Objective 3. Develop technology transfer products for a diversity of stakeholders to promote adoption of microirrigation.

In objective 1 above, the automatic collection, evaluation, and deliver of soil and weather data is described. The goal was to interpret and deliver results, predictions, and projections in real time to growers' smart phones and laptops based on growers' demands. Growers are gaining real time access to information from their fields for water management decision making. These emerging tools and technology for growers have the potential to simultaneously optimize economic outcomes and minimize the losses of water and nutrients.

What opportunities for training and professional development has the project provided?

Undergraduate students were trained in research protocols and learned about crop irrigation and management.

How have the results been disseminated to communities of interes