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The American Society for Horticultural Science (ASHS) has since its inception published annual serial monographs or journals to achieve its mission of communicating horticultural science. To recognize the accomplishments of the membership, a series of professional awards was created. After the individual awards, the ASHS created publication awards. This paper, and the papers that follow, document the publication awards of the ASHS. The papers were based on presentations at the 2023 annual conference and serve as additional recognition of the contributions of member authors and as a historical record of achievements of the ASHS.

Open Access

Nitrogen (N) management is a key component to maintaining high productivity of northern highbush blueberry (Vaccinium corymbosum L.) and nitrogen is often supplied by applying ammonium-based fertilizers. It can also be supplied through mineralization of soil organic matter (SOM), although the amount released by SOM is difficult to predict and not always considered in the development and implementation of N fertility programs. Laboratory and field experiments were conducted to estimate the timing and magnitude of net N mineralization from SOM throughout the growing season, identify soil properties that can be measured commercially and used to predict net N mineralization across a range of SOM, and determine whether N requirements for maximizing yield and fruit quality of blueberry vary across soils with different amounts of SOM. The laboratory experiment was conducted for 6 months using soil samples collected from 10 representative commercial blueberry fields in northwest Washington. The soils contained 2% to 42% soil organic carbon (SOC). The mean net N mineralization rates were fastest during the first 3 to 4 months of incubation, corresponding to the period during which N uptake reaches its maximum in blueberry. Results indicated that the soil total N may be a useful predictor of the N supply from SOM (6.34 ± 1.13 kg⋅ha−1 increase in net N mineralization with each 0.1% increase in total N), but there was substantial variability in the N supply that could not by explained by the total N (P < 0.001; r2 = 0.433). The field experiment was conducted from 2019 to 2021 and included four mature, regionally representative, commercial fields of ‘Duke’ blueberry. The fields contained 3% to 28% SOC and were each fertilized with low, medium (control), or high N rates, corresponding to 33 to 50, 67 to 84, or 102 to 118 kg⋅ha−1 N per year, respectively. Although soil inorganic N levels suggested that N mineralization was substantial at sites with higher SOM, sites with lower SOM did not require more fertilizer N than those with higher SOM. Under the conditions of this experiment, even the lowest N rates were sufficient to sustain production for at least 3 years at each site. The findings of this study indicate that SOM may be an important contributor to N fertility in managed blueberry systems, and that yield and fruit quality can be maintained across various N fertilizer rates, including at rates <50 kg⋅ha−1 N. However, the long-term impacts of reducing N application rates remain unclear, and future research should monitor long-term changes in plant health and soil fertility associated with reduced N applications across diverse soils and production systems.

Open Access

Growers producing day-neutral strawberries (Fragaria ×ananassa) in temperate climates face challenges when attempting to extend the season and mitigate the effects of rain. Conventional plastic coverings over low tunnels have been used for these purposes, but they often exacerbate heat-induced problems in summer. We examined two approaches for addressing this challenge. The first was to start dormant bare root ‘Albion’ strawberry plants in small pots in the greenhouse, then plant them into the field in spring so they could begin production before the onset of consistently high temperatures. Plants set in small pots on 26 Feb in the greenhouse and field planted on 6 May were compared with bare root plants set directly into the field on 6 May. The second approach used various low tunnel coverings to modify the light and temperature environment around the plants. Three coverings were woven nets embedded with reflective strips at various densities that allowed 50%, 60%, and 70% light transmission, and these were intended to lower temperatures under the covers by reflecting infrared radiation. A fourth covering was a polyethylene plastic embedded with optically active additives that shift incident light into wavelengths that are more photosynthetically active. Two other covers were standard commercial polyethylene plastics, and the final treatment was an uncovered control. Over the 2020 and 2021 growing seasons (hot and dry vs. moderate and wet, respectively), plots were harvested once or twice a week from June through October and fruit yield, size, and marketability were assessed. In both years, strawberry plants started in the greenhouse produced significantly higher yields than bare root plants over the season (30.5% and 43.7%). Bare root plants were less responsive to cover type than greenhouse plants. In 2020, yields tended to be higher in the middle of summer in plots with reflective coverings that reduced temperature and higher later in the season with coverings of wavelength-shifting film. Polyethylene covers that increased temperature without shifting the light spectrum had lower yields. Under the cooler conditions of 2021, plants under covers that increased temperature tended to have higher yields. In a third year (2023), bare root plants were covered with a reflective covering from 29 Jun until 1 Sep, then this cover was replaced with polyethylene with optical additives as the weather cooled and light levels dropped. This sequenced treatment was compared with uncovered plots and plots covered with standard commercial polyethylene plastic. Plants under the two-phase sequential covering performed significantly better than uncovered plots or those covered with standard polyethylene plastic alone.

Open Access

To provide reference for the design of the air-suction tea sorting device, the coupled numerical simulation model was established by the coupling method of computational fluid dynamics (CFD) and discrete element method (DEM) with tea of different quality as test objects, and the model was verified experimentally. Regarding tea particles of different quality, when the test tea particle mass was 0.215, the test value was located in the simulation value with a minimum error of 9 mm, which an error rate of 3.33%, and maximum error of 19 mm, with an error rate of 7.03%. When the test tea particle mass was 0.145, the minimum error of the test value was 5 mm and the error rate was 1.54%, and the maximum error was 9 mm and the error rate was 3.33%. The verification results established the accuracy of the model. During the suspension test and simulation, tea particles were affected by the air flow field of the observation tube, and tea particles fluctuated. During suspension, tea particles were attached to the inner wall of the observation tube under the action of the air flow field. An in-depth study showed that the relationship between the different distances from the initial position of the particles during suspension and the simulation time was a peak function. The extreme function is used to fit the actual trajectory, and the fitting degree is good. The fitting degree of the particle closest to the initial position was 0.9455, and the fitting degree of the particle farthest from the initial position was 0.9981.

Open Access

Sowing density is a key management practice influencing productivity and quality of leafy greens and culinary herbs grown in controlled environments. However, research-based information on optimal density is limited for many culinary herbs. This greenhouse study aimed to quantify sowing density impacts on biomass output, individual plant growth, and morphological traits in hydroponically produced ‘Giant of Italy’ parsley (Petroselinum crispum), ‘Santo’ cilantro (Coriandrum sativum), and sage (Salvia officinalis). Seedlings were grown in phenolic foam cubes with 1, 5, 10, 15, or 20 seeds per cell, transplanted into an ebb-and-flow hydroponic system in a glass-glazed greenhouse with 23 °C target average daily temperature, 16-hour photoperiod, a target daily light integral of 13 mol·m−2·d−1, and harvested at 16 to 28 d after transplanting depending on species. ‘Giant of Italy’ parsley and ‘Santo’ cilantro fresh weight per cell increased quadratically by 274% (57.3 g) and 305% (19 g), respectively, as sowing density increased from 1 to 15 seeds per cell, then plateaued as density further increased. Sage fresh weight plateaued at 10 seeds per cell with an increase of 225% (29.2 g) compared with 1 seed per cell. Cilantro and sage dry weight per cell plateaued at 14 and 8 seeds per cell, respectively, and parsley dry weight quadratically increased as sowing density rose up to 20 seeds per cell. Although fresh and dry weight increased, individual plant height, stem diameter, and individual plant dry weight exhibited linear or quadratic declines as sowing density increased, indicating higher sowing densities restricted individual plant growth. In summary, as sowing density increased, fresh and dry weight per cell generally increased but individual plant quality decreased. For the greatest fresh and dry weight, 20, 18, and 10 seeds per cell should be sown for parsley, cilantro, and sage, respectively. However, to balance fresh weight and crop quality, our results suggest sowing density (seeds per cell) targets of 16 seeds for parsley, 18 seeds for cilantro, and 10 seeds for sage.

Open Access

Ornamental plant and weed response to oxyfluorfen + prodiamine herbicide was evaluated in Connecticut and Tennessee, USA, in 2017 and 2018. Preemergence application of oxyfluorfen + prodiamine was made at 0 lb/acre, 2 + 0.75 lb/acre, 4 + 1.5 lb/acre, and 8 + 3 lb/acre to container-grown ornamental plants on an outdoor gravel pad and weeds in greenhouse experiments. Ornamental plants were treated first within a week after transplanting and again 6 weeks after the first treatment. Asiatic jasmine (Trachelospermum asiaticum), candlestick plant (Senna alata), and English ivy (Hedera helix) in Tennessee, USA; and ‘Blue Flag’ iris (Iris sp.), ‘Firecracker’ gladiolus (Gladiolus sp.), and ‘Green Carpet’ Japanese pachysandra (Pachysandra terminalis) in Connecticut, USA, were not injured with oxyfluorfen + prodiamine regardless of rate applied. Lily-of-the-Nile (Agapanthus africanus) in Tennessee, USA, and ‘Bowles’ periwinkle (Vinca minor) in Connecticut, USA, showed minor but commercially acceptable growth reduction with oxyfluorfen + prodiamine up to 4 + 1.5 lb/acre. Shasta daisy (Leucanthemum ×superbum) in Connecticut, USA, was the most sensitive ornamental plant. After the first application, average necrotic injury to Shasta daisy varied from 24% with 2 + 0.75 lb/acre to 31% with 8 + 3 lb/acre of oxyfluorfen + prodiamine. After the second application, necrotic injury was ≤ 5% with all oxyfluorfen + prodiamine rates tested and was commercially acceptable (≤ 20%). Oxyfluorfen + prodiamine reduced densities of creeping woodsorrel (Oxalis corniculata), hairy bittercress (Cardamine hirsuta), giant foxtail (Setaria faberi), and large crabgrass (Digitaria sanguinalis) ≥ 80% by 4 weeks after treatment. The fresh weed biomass 6 weeks after treatment indicated an 88% to 99% reduction compared with the untreated control.

Open Access
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This study investigated whether coding (computer programming) and horticultural activities alone and combined have psychophysiological and psychological effects. Compulsory computer programming has been required in elementary schools in South Korea since 2018. A total of 34 participants, who were students between the ages of 11 and 16 years were involved in the study. Participants undertook the following activities in random order: connecting components, coding, horticultural activities, and combining coding and horticultural activities (run program, horticultural activities, and coding modifications). Brain waves were measured during the activity, and a subjective self-report evaluation was conducted at the end of each activity. In a spectral edge frequency of 50% of the alpha spectrum band, which indicates a comfortable, stable, and relaxed state, there was a significant difference in the left prefrontal pole when participants performed a combination of coding and horticultural activities (P < 0.001). In addition, there were significant differences in the coding activities based on horticultural activities (P < 0.05, P < 0.001), with a relatively low beta, indicating attention and alertness; relative mid beta, indicating active awareness; ratio of SMR to theta, indicating focused attention; and the ratio of mid beta to theta, indicating concentrated focus. It is judged that activities involving plant engagement can contribute to comfort, stability, focused attention, and positive effects in response to active stimuli. As a result of a subjective evaluation, it was found that horticultural activities had a positive effect on participants’ emotions (P < 0.01). This study demonstrates that horticulture-based coding activities have a positive impact on physiological relaxation and cognitive enhancement, and are also associated with subjectively reported positive emotions.

Open Access

The renowned horticultural artist and plant breeder Luther Burbank worked with many species of plants. During his 50-year career, he introduced more than 800 cultivars, including more than 150 accessions of plums (Prunus spp.) in the late 1800s and early 1900s. Burbank preferred using wide, interspecific crosses to create a vast range of phenotypic variation and then artificially select from the extremes. Although a great artist, Burbank was a substandard scientist because he was derelict in pedigree note-taking. Although many of his introductions are extinct, hobbyists, enthusiasts, and international collections retain nearly a third of the economically viable cultivars he bred. For a century, many of his hybridizations remained inscrutable mysteries until modern genomic and computational tools developed their resolution and statistical power. Today, genotyping by sequencing (GBS) is a useful tool for pedigree reconstruction in the absence of reliable records. GBS can inform principal component analyses, identity by descent (IBD) kinship, and phylogenetic admixture, revealing complex relationships among taxa. In this study, whole genome sequencing was performed on 53 Prunus taxa used by Burbank in his breeding experiments in the most comprehensive genetic survey of his work to date. Exact parent–offspring relationships between this population may be impossible to discern due to years of back crossing, sibling mating, and open pollination. However, the proportion of genomic similarity among these taxa provides information on the relatedness of the genotypes in Burbank’s Prunus experiments, defining four primary lineages within his breeding population. These lineages comprised primarily P. salicina and P. simonii but also have influences from P. americana, P. cerasifera, P. domestica, and P. rivularis. The prevalence of P. simonii in Burbank’s Prunus introductions appears to have been vastly underreported, indicating that some of the seedstock founders of his breeding population could have been P. salicina × P. simonii hybrids at the inception of his career. This research has implications for pedigree reconstruction and prioritizing conservation in collections curation for future studies.

Open Access

Hydroponics is widely used in greenhouse and vertical farming production because these facilities can precisely control environmental conditions such as lighting, temperature, and vapor pressure deficit. However, the fertilizer solutions have a short life span, and they often do not have adequate microbial populations to enhance plant growth. Previous studies have shown the potential of beneficial microbes to promote plant production and alleviate abiotic and biotic stressors in the field, and studies on their use in controlled environments such as greenhouses and vertical farms are limited in the literature. In this study, we selected several plant growth promoting microbes (PGPMs) and tested their effects on alleviating salinity stress in ‘Rex’ lettuce (Lactuca sativa) and ‘Red Pac’ pak choi (Brassica chinensis) grown in deep water culture hydroponics. Our goal was to use one stressor, salinity, that induces profound symptoms in plant morphology. A three-cycle study was conducted using five PGPMs [Bacillus, Glomus, Lactobacillus, Trichoderma, and Bacillus/Pseudomonas/Trichoderma (B/P/T) mix] and two salinity levels [no salinity and salinity treatment, with 120 mM, 40 mM, and 80 mM sodium chloride (NaCl) solution used for the first, second, and third cycles, respectively]. We measured the effects of PGPMs and salinity on plant growth and quality and the solution pH and electrical conductivity (EC). Salinity stress decreased lettuce and pak choi leaf area and shoot fresh weight and increased plant leaf chlorophyll and anthocyanin contents with increased solution EC. Under high-salinity stress (120 mM NaCl), the addition of Trichoderma reduced pak choi leaf area and fresh weight but increased solution pH, whereas under low salinity stress (40 mM NaCl), Trichoderma increased pak choi leaf chlorophyll content. Under moderate-salinity stress (80 mM NaCl) condition, the addition of Glomus sp. increased lettuce fresh weight and leaf area, and B/P/T mix increased pak choi leaf area. In conclusion, using the selected PGPMs in low to moderate-salinity stress could increase lettuce and pak choi growth and quality parameters. These results have some practical applications in the future when more saline water is used for production.

Open Access