ASHS 2025 Conference

A forum for discussion of potential collaborations with regards to plant growth and culture – i.e. propagation, root growth, water management, weed control, PGRs, plant nutrition, etc.

this study aimed to assess how irrigation water and seed magnetization affected the initial growth of okra, bell pepper, cucumber, lettuce, and eggplant seedlings. Five treatments and four replications were used for each species in the randomized block design (RBD) experiment. T1 was irrigation with tap water; T2 was neodymium magnetization of seeds plus irrigation with tap water; T3 was commercial magnetization of seeds plus irrigation with tap water; T4 was lack of seed magnetization plus irrigation with neodymium magnetized water; and T5 was lack of seed magnetization and irrigation with commercial magnetized water. We assessed the following: emergence speed index (ESI), average emergence time (AET), emergence percentage (E%), shoot dry matter (SDM), root dry matter (RDM), number of leaves (NL), root length (RL), stem diameter (SD), and plant height (PH). Normality and variance analysis were performed on the data, and the Tukey test was used to compare the means at a 5% probability level. The study's findings demonstrate the advantages of magnetically treated water for seedlings. Using water that has been magnetized by a neodymium magnetizer produced superior results for lettuce seedlings. The highest RL, NL, RDM, and ESI values were obtained for bell peppers when they were irrigated with water that had been magnetized by a neodymium magnetizer. The time it took for cucumber, eggplant, and okra seedlings to form was shortened by either magnetizing the seeds or watering them with tap water. Overall, the results of seed magnetism have been more noteworthy than those of irrigation water magnetization.

Agriculture continues to account for over 70% of global freshwater withdrawals, despite extensive research into water conservation methods in food production. A significant portion of this water usage is attributed to irrigation. In vegetable crops, the traditional raised bed system with plastic mulch can reduce irrigation application by minimizing evaporative losses. However, this system does not prevent water and nutrient losses to deep percolation or lateral movement outside the bed area. Therefore, this study evaluates an alternative raised bed system (H2grow), and compares its impact on water use, yield, and fruit quality in bell pepper production against the conventional raised bed system. Six treatments were tested, which included three nitrogen (N) application rates in both raised bed systems (bed type). A split-plot design was used, with bed type as the primary factor and nitrogen rates as the secondary factor. All treatments were replicated four times. Soil moisture sensors were used to trigger irrigation when soil moisture levels fall below 90% field capacity. Soil moisture, nutrient levels, and tissue nutrient content were monitored throughout the growing season. Yield and fruit quality (fruit wall thickness), were assessed at harvest. Preliminary results show that cumulative water use under the H2grow was 33% lower than the conventional raised bed, regardless of nitrogen application rates. This corresponds to a water savings of 1460 m³/ha. Although there were no significant differences in yield or wall thickness between bed types; the H2grow system showed promising potential over conventional beds with a p-value of 0.08 for yield and 0.06 for wall thickness. Nitrogen application rates had no significant effect on yield or fruit wall thickness, though fruit biomass was lowest under the low-N treatment. These findings demonstrate that the H2grow system significantly conserves water in bell pepper production and has the potential to reduce the water footprint in commercial vegetable production. As water conservation becomes an increasing concern in agriculture, this innovative technology offers a critical solution to address the growing challenge of freshwater use in food production.

Strawberry production in Florida traditionally relies on impact sprinklers for bare-root transplant establishment and freeze protection, leading to significant water consumption and potential nutrient leaching and runoff. This study assessed micro-sprinkler systems as alternatives to enhance water use efficiency while maintaining crop performance. The objectives were to (1) evaluate micro-sprinklers in research and commercial settings and (2) assess sprinkler distribution uniformity under different wind conditions. Field trials at the Plant Science Research and Education Unit in Citra, FL compared four micro-sprinklers to an impact sprinkler (control), measuring water use, plant vigor, and yield. The tested systems utilized Mini Revolver, SuperNet Jet, Mini-Wobbler, and Xcel Wobbler micro-sprinklers. The irrigation systems were arranged in a randomized complete block design with four replications. Additionally, lower quarter distribution uniformity (DUlq) tests with catch cans were conducted to evaluate sprinkler efficiency for freeze protection across varying wind conditions in Citra. The best-performing micro-sprinkler system was evaluated on a commercial strawberry farm in Plant City, FL in comparison with the grower’s Rotator sprinkler system. In Citra, all micro-sprinkler systems used less water than the impact sprinkler for bareroot transplant establishment and freeze protection. Water use was lowest with the Mini-Revolver, which decreased water use by 66% during establishment and 64% during freeze protection without adversely affecting plant survival or yields. Similar reductions were observed at the commercial farm, with water savings reaching 58% during establishment and 63% during freeze events. Significant variation in DUlq in response to wind conditions was observed among the sprinkler systems. Wind speeds >7 mph decreased DUlq, with the Mini-Revolver resulting in the lowest DUlq. However, at wind speeds 7 mph, which would decrease freeze protection effectiveness.

Deficit irrigation is an agricultural practice that can enhance crop water productivity (CWP) when yields are not affected, and be a technique to support crop production under persistent droughts and reduced agricultural water availability. Over two seasons, we evaluated grafted and ungrafted cantaloupe melon (Cucumis melo L.) under three consistent irrigation regimes: 100% of field capacity (FC; full irrigation), and 70% and 50% irrigation volumes of the full irrigation, resulting in moderate and severe deficit irrigation treatments, respectively. Although the deficit irrigation treatments accentuated drought stress through the season, plants in the moderate deficit irrigation (70% FC) maintained their plant water status and slightly lowered stomatal conductance (gs) and photosynthetic rate (Pn) when compared to full irrigation. Under severe deficit irrigation (50%), plants had lower water potential than the full irrigation, and a reduction of 65% in gs and 47% in Pn, when compared to the full irrigation. The yields of the 100% and 70% irrigation treatments were similar in one year and lower for the 70% FC in the second year. The severe deficit irrigation had on average a 40% lower yield than the full irrigation. Overall, the moderate deficit irrigation had a 25% reduction in applied water, and either a similar or a higher CWP, depending on year, when compared to the full irrigation. Melon grafting did not improve yield under deficit irrigation conditions; however, it increased yield under full irrigation and low environmental stress (i.e., year). This study shows that melons can acclimate to lower water availability and sustain yields under a constant, moderate deficit irrigation, which can be an alternative for growers that face long-season droughts and lower irrigation water allocation.

Sustainable management of irrigation water is critical for soilless greenhouse production systems, particularly in ornamental plant cultivation, where agrochemical (pesticides, nutrients, and growth regulators) use is intensive. Recycled irrigation water carries agrochemicals from production surfaces, containers, substrates, and system components. Even at low concentrations, these compounds can be phytotoxic to sensitive crops or pose environmental risks if discharged. While recirculating irrigation systems improve water efficiency, they require the use of treatment technologies to remediate agrochemicals. Woodchip bioreactors, commonly used for nitrate removal, have also shown promise in remediating phosphates and pesticides. They provide a carbon source and growth matrix for diverse microbial communities. Typical anaerobic conditions facilitate denitrification, and the biofilm further increases the reactive surface area where pesticides can interact with degrading enzymes to enhance pesticide remediation. Integrating aerobic bioreactors as a secondary stage can promote dissolved organic carbon release and enhance degradation of certain pesticides. Hydraulic retention time (HRT) is a key design factor, influencing nutrient retention and pesticide removal by controlling contact time with bioreactor microbiomes. Shorter HRTs support nutrient recycling for irrigation reuse, while longer HRTs enhance nutrient and pesticide degradation through extended microbial processing. We evaluated the performance of a sequential two-stage non-aerated (stage 1) - aerated (stage 2) bioreactor configuration in reducing effluent pesticide concentration and load under varying hydraulic retention times (HRTs). Two two-stage systems, each consisting of two bioreactors, were installed at a Michigan wholesale greenhouse, treating recirculating operational water from an 11,500 m² production area. These systems operated for 160 days at HRTs of 30 (30HRT) and 60 minutes (60HRT) per stage, corresponding to bioreactor volumes of 1,135 L and 2,271 L per stage, respectively. Preliminary results indicate that both 30HRT and 60HRT systems treated an average daily volume of 36,225±2,395 L. Average recycled Total Nitrogen load was 91% and 2.6 kg d-1 for 30HRT, and 78% and 2.3 kg d-1 for 60HRTs, respectively. Phosphate and pesticide content is currently being analyzed, with early observations showing phosphate load shifts from non-aerated to aerated conditions. These results will be presented at the conference.

Irrigation return water (IRW) from the nursery and greenhouse industries contains agrochemicals (pesticides, nutrients, and growth regulators) that pose significant phytotoxic and environmental risks within the operation and to the surrounding ecosystem. Agrochemicals can contribute to plant injury, eutrophication, groundwater contamination, and ecological toxicity. Woodchip bioreactors offer a cost-effective, sustainable solution for contaminant mitigation by supporting diverse microbial communities. Under anaerobic conditions, woodchip bioreactors facilitate nitrate reduction, while biofilms enhance pesticide degradation via enzymatic activity. Hydraulic retention time (HRT) regulates the duration of contaminant-microbiome interactions, balancing nutrient recycling in IRW at shorter HRTs and enhanced pesticide degradation at longer HRTs. However, newly established bioreactors typically experience a lag phase before reaching optimal contaminant removal efficiency due to the time required for microbial communities to develop. In this study, we investigated the potential of seeding new bioreactors with biofilms from established systems to accelerate this transition. Thirty-six woodchip bioreactors were evaluated under three HRTs (4, 14, and 24 hours) and three seeding levels (0%, 5%, and 10%) over 170 days. Simulated IRW containing nitrate, phosphate, and eight pesticides (acephate, atrazine, bifenthrin, chlorpyrifos, cyazofamid, oxyfluorfen, sulfoxaflor, and thiophanate-methyl) was used to assess performance. Preliminary results indicate that the 10% seeding at 4HRT yields the highest total nitrogen removal (6.2 g/day), compared to the 5% seeding at 4HRT (3.1 g/day) and the unseeded treatment at 4HRT (2.8 g/day). This suggests that a higher microbial load, combined with a shorter retention time, may be the most effective approach for removing Total Nitrogen.

In-situ resource utilization at the lunar surface has been proposed for food production during human exploration missions. However, lunar regolith’s sandy texture holds less plant-available water than most of Earth's fine-textured agricultural soils. Reduced gravity at the lunar surface limits drainage from containerized media, likely causing root-zone hypoxic stress without appropriate irrigation management. Sensor-based irrigation systems may mitigate these challenges by maintaining an optimal medium volumetric water content. Evaluating the palatability of crops is also crucial, though sensory evaluation is uncommonly included in crop production studies. Hence, this research aimed to quantify the effects of sensor- and time-based irrigation strategies on the development and growth of Lactuca sativa (lettuce) grown using two continuous harvesting techniques in a containerized Turface MVP medium, a coarse calcined clay aggregates. Lettuce seeds were sown in 48 containers filled with the Turface MVP (particle sizes 0.8-3.4 mm) premixed with 15N-3.9P-10K controlled release fertilizer. Additionally, 24 containerized media were left unseeded to serve as controls. The containerized media were randomly assigned to sensor- and time-based irrigation under “pick-and-eat” and “cut-and-sow” harvesting techniques. Sensor-based irrigation maintained volumetric water content at 0.40 m3·m-3 through frequent sensor scanning and automated irrigation when sensor readings fell below the setpoints, while the media at time-based irrigation management were irrigated to saturation once per day. Under the “pick-and-eat” method, sensor-based irrigation increased the leaf fresh and dry weights, and photosynthesis rate by 81%, 39%, 61%, respectively, compared with plants under time-based irrigation at the end of experiment. The “cut-and-sow” method resulted in lower leaf fresh and dry weights than the “pick-and-eat” under both irrigation treatments. However, sensor-based irrigation led to increases in the medium’s electrical conductivity, causing plants under salinity stress because the phosphorus, potassium, and magnesium concentrations in the leaf tissue increased compared with those under time-based irrigation. Sensor-based irrigation improved overall acceptability of samples under “pick-and-eat” in sensory testing, with 50% of respondents disliking the time-based samples. However, the "cut-and-sow" samples under time-based irrigation exhibited higher overall acceptability, though 75% or more testers liked both samples. Sensor-based irrigation improved the yield of lettuce under "pick-and-eat" method but caused salinity stress. Conversely, the "cut-and-sow" method led to lower yield, but improved plant palatability under time-based irrigation. Nevertheless, with higher yield, increased mineral content, and improved consumer acceptability, the “pick-and-eat” method under sensor-based irrigation demonstrates potential for sustaining continuous crop production.

Open to all attendees.

Understanding the partitioning of evapotranspiration (ET) into soil evaporation and plant transpiration is critical for improving irrigation management in young orchards with limited canopy cover. This study focuses on partitioning ET in a 4-year-old drip irrigated pistachio orchard located in the Mesilla Valley, Southern New Mexico, using the Conditional Eddy Covariance (CEC) method. The orchard is equipped with a high-frequency eddy covariance system along with sensors to make meteorological measurements. The CEC approach was applied to identify and isolate flux contributions under specific atmospheric conditions, thereby separating transpiration-driven and evaporation-driven fluxes. The CEC separates fluxes using conditional sampling based on the hypothesis that when transpiration is dominant, CO₂ and H₂O fluxes should be highly correlated. Preliminary results show that the total ET values measured from June to August varied between 1.5 and 4.5 mm/day, with about 20% contributed through transpiration from the plants in the year 2024.

Walnut is currently grown on over 400 thousand acres in California with the majority of production in the Northern San Joaquin Valley (NSJV). The recurring droughts and climate change in California will likely increase the uncertainty in water supply to walnuts and other specialty crops. Site-specific irrigation is critical to cope with these challenges. Knowing the water use of walnuts is crucial in optimizing irrigation management since it affects nut quality, and productivity. Unlike traditional methods, which are often limited by spatial coverage, high costs, and less precise crop coefficient values, satellite remote sensing offers a cost-effective, widely accessible solution. It enables large-scale evapotranspiration (ET) estimation with increasing adoption in irrigated agriculture, providing a valuable tool for water management. This study compares OpenET models, an open-source database providing ET estimates, against commercial in-situ surface renewal ET sensor. Utilizing OpenET platform provides a good opportunity for growers to improve water use efficiency. Such improvements could lead to the adoption of publicly available irrigation management tools and ensure healthier tree development, better resource utilization, and more resilient orchards in the face of climate change. Based on the data of 2024 season, the Satellite Irrigation Management Support (SIMS) model had the highest accuracy in estimating actual ET when compared to measurements from a commercial in-situ surface renewal system in the orchard, with a mean percent error (MPE) of -18.45%, and R² and mean absolute error (MAE) values of 0.88 and 0.03 inches/d⁻¹, respectively, followed by the Ensemble model. In contrast, the SSEBop model showed the lowest correlation with ETa, with an R² of 0.77 and a relatively high MAE of 0.06 inches, indicating a higher level of uncertainty in its estimates which could potentially lead to over-irrigation if adopted without correction. Based on these findings, growers can confidently incorporate the OpenET SIMS model into their irrigation scheduling, ultimately enhancing water use efficiency. However, further validation through replication over a second year and across multiple sites is essential to substantiate these findings.

Water scarcity is one of the major challenges facing the agricultural industry, necessitating the use of treated wastewater for irrigation purposes. However, not all crops can effectively utilize this water, as it may have negative effects on plant growth, including disruptions in nutrient uptake and photosynthesis. This study aimed to evaluate the effects of treated wastewater on the growth of rose-scented geranium (Pelargonium graveolens) and English lavender (Lavandula angustifolia). The experiment was conducted between 2022 and 2023 at the University of Fort Hare, Dikeni, South Africa. Two harvests were carried out in May 2023 (Harvest 1) and October 2023 (Harvest 2). Five irrigation treatments were applied to both geranium and lavender plants, consisting of treated wastewater from Dikeni town mixed with tap water at varying proportions: 0%, 25%, 50%, 75%, and 100% (v/v). Water and soil used were tested for nutritional composition. Treatments commenced four weeks after transplanting from cuttings, and the experiment followed a completely randomized block design with four replications across four blocks. The results showed no treatment differences in stem diameter, number of shoots, or plant height across treatments for both plant species during the two harvesting seasons. However, English lavender plants irrigated with 25% wastewater exhibited a slight increase in plant height at week 11, while geranium plants treated with 75% wastewater showed an increased plant height from week 5 until harvest at week 11. Additionally, plants receiving the 25% wastewater treatment produced the highest number of shoots from week 8 to week 11. These findings suggest that treated wastewater, both in its diluted and undiluted form, did not adversely affect plant growth. Therefore, it has the potential to serve as an alternative water and nutrients source for geranium and lavender plants, which farmers could utilize in collaboration with local municipalities to mitigate water scarcity challenges. However, further studies, particularly under open-field conditions, are needed to validate these results.

Runoff containing excess nitrogen (N) and phosphorus (P) is detrimental to environmental and human health. Bioreactors are biological treatment systems that can be used to combat these problems, which often consist of a lined trench filled with a carbon-rich media (often woodchips) to promote biological remediation through denitrification and other processes. Various carbon-rich organic materials, such as woodchips and sugarcane bagasse (a byproduct of sugarcane production), can be used to fuel biological processes, whereas inorganic materials, such as expanded shale, can provide binding sites for P adsorption as well as physical stability within medias. Raingarden installations utilize similar concepts for trapping runoff water and remediating contaminants; however, the inclusion of ornamental plants provides aesthetic appeal, an important consideration in urban and suburban areas. Seven unique medias were evaluated to determine potential to a.) remediate N and P from runoff and b.) support plant life. An aged pine bark/sand media commonly used for landscape beds (bed mix; BM) served as the control. Organic carbon sources (woodchips (WC) and sugarcane bagasse (SB) to support bacterial communities) and several inorganic materials (including expanded shale (S) and activated aluminum (AA) to bind P) were blended with BM to provide potential enhancement of nutrient removal capabilities. Media blends were homogenized by hand before being transferred into media containers (MC; 2.36 L of substrate per container), wherein Hibiscus moscheutos ‘Luna Pink Swirl’ seedlings were transplanted. Pots were placed within plastic containers (leachate containers (LC)), which served as a collection receptacle for leachate. Simulated runoff water containing N and P was prepared and applied to each replicate, after which leachate was analyzed and collected as sub-samples. Simulated runoff applications were limited in the initial phase of the study (one application per week; three total) and intensified in the final phase (three applications per week; nine total), with all leachate volumes collected between applications. Health and growth of Hibiscus was assessed via SPAD readings, growth index, and destructive harvest at the termination of the study. While the growth of all Hibiscus replicates was generally equivalent between treatments, it was observed that BM amended with SB produced more shoot biomass. Additionally, leachate nutrient content and water chemistry dynamics were influenced by several of the investigated amendments.

Green infrastructures, when implemented, need to consider the specifics of the local area and climate. The semi-arid climate along Colorado’s front range creates a challenge for plants in green infrastructure systems such as bioretention facilities and green roofs. These plants experience inundation and fast infiltration during rain events and long periods of hot and dry conditions between storms. To accommodate these periods of inundation and drought, Colorado native plants were evaluated due to their adaptation to the challenging conditions that occur in green infrastructure. The experiments in this study are intended to build upon existing work performed by our collaborators and funders Mile High Flood District, the City and County of Denver, and Colorado State University. We aim to improve green infrastructure facility design by using new bioretention media mixes, amended native soils with 5% compost (SSC) and amended native soils with biochar and zeolite (SBZ), green roof components/systems, new plant growth and establishment strategies, and lower irrigation regimes. In 2023 and 2024, data on plant survivability were collected from the bioretention facilities and the green roofs using 100 containerized and bare-root plants. The five native Colorado species selected were Agastache rupestris, Liatris ligulistylis, Amorpha canescens, Ratibida pinnata, and Schizachyrium scoparium. L. ligulistylis, in container, had a higher survival rate after one year on the green roof, on the other hand, it had a low survival rate after a year in the bioretention facilities. The bare-root L. ligulistylis had a higher survival rate, especially in the SSC media. A. canescens, bare-root, had a higher survival rate in the SSC media, while only 25% survived in the SBZ media. All other species overwintered and grew larger the second year on the green roof and bioretention facilities. The Colorado native plants tolerated challenging conditions better than the nonnative plants in the surrounding area.

Lettuce (Lactuca sativa) is a key winter vegetable with significant consumptive water use in the Lower Colorado River Basin, especially in Yuma, AZ. Generally, lettuce requires about 300 – 400 mm to produce a desirable crop, which can vary significantly depending on irrigation method, soil type, field slope, temperatures, and planting window. However, the magnitude of the quantified differences in seasonal evapotranspiration and crop water productivity among different irrigation scheduling strategies under the subsurface drip irrigation method for organic vs. conventional iceberg lettuce production systems has not been sufficiently investigated. Field experiments were conducted in the fall 2024 growing season at the Valley Research Center at the University of Arizona Yuma Agricultural Center, Yuma, Arizona. This project was conducted in a one-acre field (half-acre organic field and the other half conventional field) under the subsurface drip irrigation method with two irrigation scheduling strategies (sensor-based irrigation (SI) and traditional irrigation (TI) based on growers' standard decision basis that is common in the Yuma area. The field was planted with the iceberg lettuce variety SVLD0023 on October 29th, 2024, on Gadsden clay loam soil. The fertilizer treatments imposed included (1) organic fertilizer, (2) combined biostimulant and organic fertilizer in an organic lettuce field, (3) nitrogen, and (4) combined biostimulant and nitrogen in a conventional lettuce field. Each treatment was replicated three times within each experimental block. Each experimental unit had three beds, and each bed was approximately 120 feet long and 3.5 feet wide, with a randomized complete block design. The objectives of this project include: (1) quantify and compare the seasonal iceberg lettuce evapotranspiration between organic and conventional iceberg lettuce production systems, (2) measure and compare the crop water productivity, and irrigation water use efficiency between two irrigation scheduling strategies for organic and conventional iceberg lettuce production systems, and (3) quantify and compare improvements in soil water retention under the combined application of biostimulant and organic fertilizers in organic lettuce versus the combined application of biostimulant and nitrogen in conventional lettuce. Data collection is currently in progress and will be analyzed in a manner consistent with the experimental design and the objectives of the study. Results will be presented with preliminary conclusions and directions for further research.

While approximately 80 to 90% of the sprinkler-applied water to a strawberry crop is lost through runoff, deep percolation and evaporation, all the strawberry fields in Ventura County are still irrigated with overhead sprinklers during crop establishment. Even though water use-efficiency for the in-season irrigation is on average high, the escalating regulatory pressure to achieve sustainable groundwater use in California, and therefore limiting water availability, will demand further efficiency. This study quantified differences in water use, yield, canopy coverage and root depth between drip tape (DT) and micro-sprinkler (MS) irrigation during crop establishment at a commercial field located in Oxnard, CA during the 2023-2024 and 2024-2025 growing seasons. This abstract shares the results of the second season. The treatments were applied during the first 42 days after planting, after which drip tape became the only irrigation method. The irrigation scheduling of the MS treatment was defined by the irrigator (grower standard), while the DT irrigation was guided by tensiometers and field observations. All other production practices remained the same. Each treatment was replicated four times in a randomized complete block design, with an area of 0.15 acre per plot (7 beds of 175ft long). Total water use during establishment was 74.4% greater for the MS treatment compared to DT (5.8 and 3.4 acre-in, respectively). Marketable yield up to March 31 was very similar between treatments (19,268 and 19,420 lb/acre for DT and MS, respectively) and not statistically significant (p-value = 0.9517). Although not statistically significant, canopy cover MS was 9 and 11% greater at 1 month and 3 months after planting, respectively. Root depth measured at 1 month after planting was very similar and not statistically different (p-value = 0.9496).

Agricultural runoff can contaminate surface and groundwater through the accumulation of nitrate-nitrogen (NO3-N) and phosphate-phosphorus (PO4-P). The Gray Water Footprint (GWF) estimates the volume of freshwater required to dilute pollutants to achieve target water quality standards. GWF can be used to compare the environmental impact of agricultural practices, such as irrigation and fertilization. In this project, we estimated and compared the GWF of three irrigation systems and two fertilizer rates in the production of Petunia milliflora F1 (Picobella Pink) in greenhouses. The experiment was a split plot design with two factors: irrigation (overhead, drip irrigation, and subirrigation) and control released fertilizer (CRF) rates (2.1gN-1.26gP-1.68gK or 1.8gN-1.08gP-1.44gK per pot). Plant growth and leachate were measured weekly. GWF was estimated with nitrate or phosphate from the leachate recovered from the containers. Significant differences were observed by irrigation system, but not by CRF rate or the interaction between the factors. In general, GWF (L of water to dilute the pollutant) of phosphate was higher than nitrate. The subirrigation, closed irrigation system had zero GWF because it does not release any leachate. Fertilizer inputs can be reduced while effectively maintaining the quality of petunia in container-production; however, it did not affect pollution rates. In contrast, the choice of irrigation system had a significant effect on nitrate and phosphate runoff rates.

Improving irrigation efficiency is essential for sustainable agricultural production. Smart irrigation technologies enhance water-use efficiency by integrating wireless communication, advanced sensors, and adaptive scheduling based on actual plant water requirements and weather conditions. Unlike traditional fixed-schedule timers, smart controllers dynamically adjust irrigation to optimize water use. This study aimed to compare three commercially available smart irrigation controllers: Hunter® Hydrawise (Hunter Industries, San Marcos, CA, USA), Orbit® B-hyve (Salt Lake City, UT, USA), and Rachio (Rachio Inc., Denver, CO, USA). The experiment was conducted at the Utah State University Greenville Experiment Station in Logan, Utah, USA. The experimental site (18.5 m x 6.4 m) comprised 12 plots (1.8 m x 1.8 m each), arranged in a completely randomized block design with three blocks, each containing four treatments (three smart controllers and one control). The control plot operated on a fixed timer: 20 minutes of irrigation daily managed by Rachio, whereas the other three smart controllers operated independently utilizing the weather data to schedule irrigation. Each plot was equipped with four sprinkler heads positioned at the corners. Controllers were installed and configured following manufacturer guidelines, utilizing Wi-Fi-enabled communication with their respective software applications. Each controller was configured, ensuring similar settings for a fair comparison, adhering to their respective technical features. Plugs of sage plants were transplanted in 7.5 L containers filled with Metro-Mix® 820 substrate. Initially, plants were irrigated daily for 20 minutes for two weeks to ensure proper establishment. Subsequently, the smart controllers managed irrigation based on real-time weather data, maintaining substrate moisture between 25-30% volumetric water content. Results showed significantly higher total water use in the control plots compared to those managed by smart controllers. Among the smart controllers, Hunter Hydrawise consumed significantly more water than Orbit and Rachio. Growth parameters including plant height, growth index, biomass, and visual appearance did not differ significantly across treatments. However, flower dry weight was significantly higher under Orbit compared to the control and Hydrawise, and similar to Rachio. Physiological parameters such as assimilation rate, stomatal conductance, maximum photochemical efficiency (Fv/Fm), Soil Plant Analysis Development (SPAD), Normalized Difference Vegetation Index (NDVI) remained consistent among all treatments. This study will be replicated during the upcoming summer to further validate the findings and enhance the reliability of the results.

Dona Ana County is one of the largest producers of pecans in the nation, making this area one of the most significant pecan production regions in the world. However, it is facing a shortage of water due to prolonged drought in the region. Management of water to grow crops, including pecan, is crucial to sustaining the agricultural industry in the region. This study assesses the evapotranspiration (ET) of a flood-irrigated young pecan orchard planted in 2021 in the Valley. This orchard has a partial canopy cover of pecan and pasture as a cover crop above the soil. In this orchard, ET was measured using an eddy covariance system and calculated as a residual using the energy budget method. Results indicate that ET primarily varies between 2.5 and 5.5 mm/day from June to August in the years 2021 and 2022.

Climate change, including rising average global temperatures, prolonged drought, and irregular weather patterns, presents significant challenges to landscape plant communities. Urban green spaces are vital to support mental health, mitigate urban heat island effects, and foster community cohesion. The objective of this project is to evaluate the drought-tolerance and ecosystem services of several ornamental plants. We hypothesize that, compared to other species, slow-growing broadleaf deciduous plants will exhibit superior drought resilience by sustaining greater biomass, attracting more pollinators, and preserving aesthetic value in the landscape. The trial was established April 20204, at Oregon State University’s Lewis-Brown Research Station in Corvallis, Oregon on a Chehalis silt clay loam. Experimental design is a randomized complete block with four replications. The single factor is plant taxa, which include 17 unique taxa of monocots, broadleaf deciduous and broadleaf evergreen, and conifer. From May 15, 2024 to Aug 30, 2024 date individual plants received an average of 1 gallon of water per week applied using a 0.5 GPH emitter. Their performance was assessed using leaf area index (LAI), plant height and width, presence of living leaves, pollinator activity, and volumetric water content (VWC). All plants survived the initial establishment in spring of 2024 and subsequent summer irrigation of 0.5 gallons per week per plant. Allium, Muscari armeniacum, and Narcissus exhibited vegetative growth in spring, fall, and winter, and summer dormancy or drought avoidance. Ceanothus, Cornus stolonifera, and Physocarpus opulifolius, being deciduous plants, retained foliage in spring, summer, and fall, and winter dormancy. After the first year, we found that broadleaf deciduous species tolerated drought while increasing in height and width, while enhancing urban green spaces during the spring and summer months. Juniperus squamata, Rosmarinus officinalis, and Arctostaphylos coloradoensis maintained year-round green vegetation. In summer of 2025 no irrigation will be applied, and data will be collated until July and presented at the this conference. After the first year, we found that broadleaf deciduous species tolerated drought while increasing in height and width, while enhancing urban green spaces during the spring and summer months. Findings from this study will provide data-driven recommendations to improve ecological management and guide the landscape industry in selecting climate-adapted species for the Pacific Northwest.

Salinas Valley is a major U.S. production region for cool-season vegetables. As regional producers work to achieve groundwater sustainability, there is a growing need to improve irrigation efficiency while sustaining crop yields. Recent advancements and availability in satellite-derived evapotranspiration (ET) data provide opportunities to inform on-farm water management. Quantifying the accuracy and limitations of these methods, however, remains important to build trust for increased operational adoption. This is especially the case for short-season vegetable crops, where performance evaluations of satellite-derived ET have been limited to-date. OpenET is a free, publicly-available platform that uses an ensemble of six satellite-based models to monitor and archive daily-to-monthly ET throughout the western U.S. at 0.25 acre resolution. In this study, daily OpenET values were compared with in-situ ET data from an eddy covariance system deployed in commercial broccoli fields during 2023 (66 days) and 2024 (76 days). Applied water was measured by an on-site digital flow meter, and precipitation was recorded by a nearby weather station. Cumulative totals from the OpenET ensemble mean were within 8.2% and 0.7% of in-situ data during the 2023 and 2024 deployment periods, respectively. Summary performance metrics were within previously published ranges for cropland sites during 2023 (mean bias error: 0.27 mm/day, mean absolute error: 0.65 mm/day) and 2024 (mean bias error: 0.02 mm/day, mean absolute error: 0.61 mm/day). Ensemble ET totals represented 88% of the 344 mm of total water received from irrigation and rainfall for the full crop cycle in 2023 (92 days), and 67% of 518 mm water received during 2024 (101 days). Results indicate OpenET quantified crop water consumption at these two sites with reasonable accuracy, while revealing differences in irrigation application efficiency. Additional discussion will address potential sources of satellite model uncertainty, challenges of collecting eddy covariance data in commercial plantings of short-season horticultural crops, and future verification efforts planned for regional high value specialty crops.

The Plants in ambient conditions are subject to dealing with biotic and abiotic stresses. Water deficit, being an abiotic stress, causes changes in plants that make them respond in several ways, such as reduced growth, leaf senescence and lower fruit growth rate, production of Reactive Oxygen Species (ROS), caused by a deficiency in the dissipation of energy due to impaired photosynthesis. The application of silicon becomes an alternative to mitigate the effects of this stress on plants, being deposited in the cell wall, providing rigidity, and increasing the plant's defense enzymes. The study aimed to understand the morphological, physical, and post-harvest responses of mini watermelon according to different soil humidity associated with the foliar application of silicon. The study was conducted in a greenhouse using the mini watermelon cv. Sugar Baby. The experimental design was in randomized blocks, in a 3x2 factorial scheme, with three water tensions in the soil (-35 kPa without water deficit, -50 kPa moderate water deficit, and -65 KPa severe water deficit) and two doses of foliar Si (0 and 1.5 g L-1), with four repetitions. The variables plant length, stem diameter and shoot dry mass, root dry mass, total soluble carbohydrates, proline, gas exchange, and post-harvest analyses were analyzed. There was a significant difference for the variables (p>0.05), but there was no interaction between tension and Si. Proline levels were not statistically significant. The water deficit promoted shorter plant length, aerial part dry mass, root dry mass and Si provided greater stem diameter. For biochemical variables, water deficit caused a higher carbohydrate content in the leaf and lower gas exchange rates. Si influenced skin thickness and average fruit weight. Thus, SI proves to be a strategy for cultivating mini watermelon in conditions of deficient water application.