Brief Summary of Minutes of Annual Meeting

The meeting was held online using the Zoom platform. Attendees joined the zoom meeting at 9 am Pacific time zone. Attendees presented station reports for their respective universities. The station reports generally took around 10 minutes followed by a five-minute question and answer session. Attendees all used PowerPoint slides to share their station reports over the zoom platform. The station report content included the accomplishments and outcomes from the past year for the different attendees. Following approximately three hours of station reports the group adjourned for a short break.  It was originally the intent to then split the group into breakout sessions for our five objectives: water quality of irrigation sources, 2. Irrigation management, 3. Crop production runoff management, 4. Urban stormwater management, 5. Soilless culture and nutrient management. However, with the relatively small group in attendance, it was deemed unnecessary to split into groups that may only have two or three at the most. Therefore we remained as an entire group and discussed our perceptions of the biggest opportunities and challenges for our working group. Climate change and the concomitant heatwaves, droughts, and floods were highlighted as the number one area our working group could have an impact in the next few years. As a group, we decided it is important to create a collective effort and host nation and international workshops on the topic of specialty crop water management. Furthermore, we will seek additional opportunities to increase the online presence of this type of teaching material.

Activities:

Researchers from Clemson University and USDA-ARS Wooster initiated sampling at two irrigation reservoirs in SC in summer 2021. From both a small (area = 0.95 acres) and large (area = 7.69 acres) reservoir, we and are beginning to capture data related to storm event runoff and reservoir refill rates, irrigation return flow, and water quality (e.g., suspended sediments, nutrients, pH, electrical conductivity, dissolved oxygen). Data (both volume and quality-based) will be integrated to characterize the movement of contaminants within water during storm and irrigation events. Growers can use this data to better inform reservoir management and refill strategies (whether storm event runoff will be adequate for irrigation needs or if groundwater pumping will also be needed). Researchers are exploring P dynamics in ponds, particularly sediment-P dynamics in irrigation ponds. They have conducted a few site visits to better understand P-dynamics in irrigation ponds. Initial conversations with the grower indicated the importance of this research for proper P and habitat management.

  Researchers at the University of California conducted another year of plant landscape irrigation trials. UC Landscape Plant Irrigation Trials determines water requirements of landscape plants Industry entries and investigator selections provides information for compliance with state water conservation regulations Project website https://ucanr.edu/sites/UCLPIT/. NC1186 members at the University of California, and Oregon State University in collaboration with non-NC1186 researchers at the Universities of Arizona, Washington, and Utah State have established a western regional irrigation plant trial to determine how climate gradient affects water use of common and uncommon landscape plant species. Researchers at the University of California also evaluated the water use efficiency of 16 ground cover species, to identify drought-tolerant species.

 Researchers are exploring the importance of the riparian area in nutrient management for developing sustainable agricultural management practices. They have identified a couple of sites in the Clemson experiment station to conduct nutrient injection studies. Results from this study could help understand the growers the importance of the riparian area, vegetation, and other in-stream best management practices that could be adopted and implemented for better source water quality. Researchers at Michigan State University conducted a multi-year study on plant establishment on freeways and from container-grown trees.

Researchers from Clemson University concluded experiments determining if phosphorus-saturated iron-oxide residuals from mine drainage could be used both (1) in filters to remove phosphorus from irrigation return flow and then (2) the P-saturated iron-oxide of the filter reused as a P fertilizer source in container production. Experiments were concluded in July. Differences in crop appearance were evident among the 5 test species. Analytical results related to leachate, plant P uptake, and P remaining in the substrate were completed and results are being analyzed for publication and communication to stakeholders. Researchers from Clemson university monitored floating wetlands paired with bioreactors and iron oxide filters (in varied order) over two winter seasons (2019-20, 2020-21) and determined that iron oxide filters enhanced P removal over winter, and supplemented removal efficacy from dormant plants in the floating wetlands and from bioreactors with reduced microbial activity due to cooler temperatures.

 USDA and Louisiana State University researchers investigated the interaction that mulch has on irrigation and weed suppression in container-grown nursery systems. Researchers at USDA and the University of Florida are investigating the water use efficiency of hydroponic nursery systems, and the interaction of different media and irrigation strategies.

 Researchers are exploring the use of technologies (both contact and non-contact sensors) for water monitoring. Adoption of these technologies by the growers could greatly help in understanding and quantifying water and nutrient budgets. Currently, some of these technologies are already in place at the Clemson campus. Researchers at Oregon State University also conducted multiple field and container trials using sensor control irrigation to reduce crop water stress and decrease excessive water use.

 The researcher educated the next generation on the importance of water quality. Study materials were developed for the minority students at Benedict Allen, an HBCU college in Columbia, SC. In the fall of 2021, the students will utilize the knowledge gained in Spring 2021 and develop a senior design project.

Abdi, D. E., Owen Jr, J. S., Wilson, P. C., Hinz, F. O., Cregg, B., & Fernandez, R. T. (2021). Reducing pesticide transport in surface and subsurface irrigation return flow in specialty crop production. Agricultural Water Management, 256, 107124.

Abdi, D. E., Owen, J. S., Brindley, J. C., Birnbaum, A., Cregg, B. M., & Fernandez, R. T. (2021). Irrigation return flow and nutrient movement mitigation by irrigation method for container plant production. Irrigation Science, 1-19.

AL-agele, Hadi A., Lloyd Nackley, and Chad Higgins. "Testing Novel New Drip Emitter with Variable Diameters for a Variable Rate Drip Irrigation." Agriculture 11.2 (2021): 87.

Bell, NL, SN Jeffers, SA White. 2021. Potential susceptibility of six aquatic plant species to infection by five species of Phytophthora. Plant Disease.

Ebba, J., Dickson, R. W., Fisher, P. R., Harris, C. N., Guerdat, T., & Flores, S. (2021). Fertilizer and Plant Growth Regulator Strategies for Improving Consumer Performance of Container-grown Petunia. HortTechnology, 31(3), 304-314.

Fields, Jeb S., James S. Owen, and James E. Altland. "Substrate Stratification: Layering Unique Substrates within a Container Increases Resource Efficiency without Impacting Growth of Shrub Rose." Agronomy 11.8 (2021): 1454.

Fields, Jeb S., and Nazim S. Gruda. "Developments in inorganic materials, synthetic organic materials and peat in soilless culture systems." Advances in horticultural soilless culture. Burleigh Dodds Science Publishing, 2021. 45-72.

LeBude, A. V., J. S. Owen Jr, and C. Holmes. "High pH, Low Alkalinity Pond Water Used for Overhead Irrigation Does Not Affect Plant Growth of Select Flowering Shrubs." Journal of Environmental Horticulture 39.1 (2021): 22-32.

Levin, Alexander, and Lloyd Nackley. "Principles and Practices of Plant-based Irrigation Management." HortTechnology 1.aop (2021): 1-11.

Levintal, Elad, et al. "eGreenhouse: Robotically positioned, low-cost, open-source CO2 analyzer and sensor device for greenhouse applications." HardwareX 9 (2021): e00193.

McCauley, Dalyn M., Lloyd L. Nackley, and Jason Kelley. "Demonstration of a low-cost and open-source platform for on-farm monitoring and decision support." Computers and Electronics in Agriculture 187 (2021): 106284.

Pitton, B.J.L., R.Y. Evans, X. Zhu-Barker, and L.R. Oki. 2021. Greenhouse gas emissions and global warming potential from a woody ornamental production system using soilless growing substrate. ACS Agric Sci Technol. 1(1):35-43. https://doi.org/10.1021/acsagscitech.0c00039.

Retana-Cordero, Marlon, Paul R. Fisher, and Celina Gómez. "Modeling the Effect of Temperature on Ginger and Turmeric Rhizome Sprouting." Agronomy 11.10 (2021): 1931.

Poudyal, S., Owen Jr, J. S., Sharkey, T. D., Fernandez, R. T., & Cregg, B. (2021). Phosphorus requirement for biomass accumulation is higher compared to photosynthetic biochemistry for three ornamental shrubs. Scientia Horticulturae, 275, 109719.

Rouse, Riley P., and Bert Cregg. "Species and season affect the response of container-grown shade trees to pre-plant root modifications." Urban Forestry & Urban Greening 63 (2021): 127184.

White, SA. 2021. Plant nutrient uptake in full-scale floating treatment wetlands in a Florida stormwater pond: 2016-2020. Water. 13:569. https://doi.org/10.3390/w13040569

White, SA, WHJ Strosnider, Chase, MEM, MA Schlautman. 2021. Removal and reuse of phosphorus from plant nursery irrigation return water with reclaimed iron oxides. Ecological Engineering. 160:106153. https://doi.org/10.1016/j.ecoleng.2021.106153