Reusing irrigation water has technical, environmental, and financial benefits. However, risks are also associated with the accumulation of agrochemicals, in addition to ions, plant and food safety pathogens, and biofilm organisms. In this project, we measured the concentration of paclobutrazol (a persistent and widely used plant growth regulator) in recirculated water in greenhouses producing ornamental plants in containers. Solutions were collected from catchment tanks at nine commercial greenhouses across seven states in the United States in Spring and Fall 2014. Paclobutrazol was detected in all samples, with differences observed by season, greenhouse operation, paclobutrazol application method, and irrigation method. Across operations, the residual concentration of paclobutrazol was higher in spring for most greenhouses (ranging from 0 to 1100 µg·L−1) compared with the fall (ranging from 0 to 8 µg·L−1). The spray-drench application method resulted in the highest residual concentrations (up to 35 µg·L−1), followed by substrate drench (up to 26 µg·L−1) and foliage spray (concentrations under 3 µg·L−1). Residual concentrations were higher with overhead irrigation (up to 35 µg·L−1) compared with subirrigation systems (up to 15 µg·L−1). Our results indicate that paclobutrazol is likely to be a growth retardant risk in greenhouse operations recirculating water. A clear understanding of the risks associated with recirculated water intends to support the development and implementation of risk management strategies to ensure and promote safe use of recirculated water in greenhouses. Overall, the most effective preventative strategy is to ensure the use of the minimum amount of the a.i. necessary per unit of space and time.
Plants native to the United States, defined as those being present before European settlement, have aesthetic and environmental benefits. In 2018, only 10% of plant sales were native plants, a plant category that tends to be underrepresented in many residential and commercial landscapes. Although earlier research indicated that consumers find native plants less aesthetically appealing relative to introduced species, more recent research reported a growing demand for native plants. Thus, a better understanding of consumer perceptions would facilitate their marketing. We used an online survey of 1824 participants representing five geographic regions (West, Southwest, Midwest, Southeast, and Northwest) to classify adopters based on their purchase of native plants. A double-hurdle model was used to estimate factors influencing purchasing native plants among US homeowners, and the factors influencing the amount spent on native plants in 2021. Demographically, metropolitan, college-educated, and younger participants were more likely to be native plant adopters; they also spent 80% more on plants compared with nonnative plant adopters. More native plant adopters agreed that native plants were better for the environment than exotic plants (68%), are readily available in their area (67%), and are better adapted to difficult sites (75%). Marketing efforts should capitalize on the environmental benefits to stimulate purchases.
Young almond (Prunus amygdalus) orchards replanted where old orchards of stone fruits (Prunus sp.) have been removed are subject to physical, chemical, and biotic stressors. Among biotic challenges, for example, is almond/stone fruit replant disease (ARD; formally known as Prunus replant disease), which specifically suppresses the growth and yields of successive almond and other stone fruit plantings and is caused, in part, by a soil microbial complex. During four orchard trials representing different almond replant practices and scenarios in the San Joaquin Valley in California, we examined the impacts of phosphorus (P) fertilization on the growth of replanted almond. During all trials, P was applied to tree root zones just after replanting, and the impact was assessed according to trunk cross-sectional area (TCSA) growth for 2 years. Expt. 1 was performed where a previous almond orchard was cleared using whole orchard recycling (i.e., the old orchard was “chipped” and then turned into the soil). The land was replanted without preplant soil fumigation. We tested separate fertilizer treatments based on various P, nitrogen, micronutrient, and “complete” formulations. Expt. 2 was also performed where an old almond orchard was recycled, but the soil was preplant-fumigated before replanting. Here, we tested only P fertilization. Expts. 3 and 4 were conducted where an old peach (Prunus persica) orchard was removed. Here, P and nitrogen fertilizer treatments were tested among additional factors, including preplant soil fumigation (Expts. 3, 4) and whole orchard recycling chips (Expt. 4). During all four trials, P fertilization (P at 2.2 to 2.6 oz/tree within a few weeks after planting) significantly increased TCSA growth. The growth benefit was nuanced, however, by almond cultivar, date of replanting, rootstock, and other site-specific factors. Although P fertilization did not match the benefit of preplant soil fumigation for the management of ARD, our data indicated that P fertilization can improve the growth of young almond orchards in diverse replant settings with or without preplant soil fumigation and should be considered by California almond producers as a general best management practice.
This study shows that plasma-fixed nitrogen applied as an inorganic biostimulant can improve marketable lettuce (Lactuca sativa var. longifolia) yield following delayed harvest. Using just one-tenth of the conventional nitrogen, plasma-fixed nitrogen—which is generated by a dielectric barrier discharge over water—was field-tested against traditional fertilization methods. Although no statistically significant differences were observed in total weight of heads among treatments, plasma-fixed nitrogen–treated plants had significantly increased marketable yields of 250% compared to those grown conventionally, despite reducing applied nitrogen fertilizer.
Near infrared (NIR) spectroscopy can be applied to nondestructively assess soluble solids concentration (SSC) of ripening, physiologically mature ‘Geneva 3’ kiwiberries (Actinidia arguta). Spectrographic signatures were captured using a handheld NIR produce quality meter to build predictive models of internal fruit quality for ‘Geneva 3’ kiwiberries that had been held under cold storage (CS) conditions (0 to 1 °C, >90% relative humidity) as well as those not subjected to CS. The CS model, constructed using scans of 133 berries following 4 to 6 weeks in CS, predicts SSC using NIR wavelengths in the range of 729 to 975 nm. A total of 507 berries fresh from the vine were used to construct a predictive model for SSC of non-CS fruit using the same wavelength range. In each case, model predictive performance was investigated using split-half cross-validation, resulting in mean absolute error (MAE) values of 1.2% and 0.8% SSC for the CS and non-CS model, respectively. Each full model was then used to predict SSC of kiwiberries subjected to the alternative CS condition. The non-CS model maintained a low MAE (1.6% SSC) when applied to CS fruit, but the MAE of the CS model applied to non-CS fruit rose considerably (4.5% SSC). The performance of a combined model was tested against both CS and non-CS models, and a benefit to using tailored, CS-specific models was found, particularly in light of cross-seasonal results. As it has proven in many crops, NIR spectroscopy appears to be a promising tool for nondestructively assessing SSC in ‘Geneva 3’ kiwiberry fruit, with accuracy being enhanced by training models specific to postharvest regimes and/or defined ranges of SSC.
Overwinter mustard cover crops incorporated into soil may suppress early-season weeds in chile pepper (Capsicum annuum). However, the potential for mustard cover crops to harbor beet leafhoppers (Circulifer tenellus) is a concern because beet leafhoppers transmit beet curly top virus to chile pepper. The objectives of this study were to determine the amounts of a biopesticidal compound (sinigrin) added to soil from ‘Caliente Rojo’ brown mustard (Brassica juncea) cover crops ended on three different days before beet leafhopper flights during spring and to determine the effects of the cover crop termination date on weed densities and hand-hoeing times for chile pepper. To address these objectives, a field study was conducted in southern New Mexico. In 2019–20, the cover crop was ended and incorporated into soil 45, 31, and 17 days before beet leafhopper flights. In 2020–21, cover crop termination occurred 36, 22, and 8 days before beet leafhopper flights. Treatments also included a no cover crop control. Cover crop biomass and sinigrin concentrations were determined at each termination. Chile pepper was seeded 28 days after the third termination date. Weed densities and hand-hoeing times were determined 28 and 56 days after chile pepper seeding. In 2019–20, the third termination (17 days before beet leafhopper flights) yielded the maximum cover crop biomass (820 g⋅m−2) and greatest sinigrin addition to soil (274 mmol⋅m−2). However, only the second termination (31 days before beet leafhopper flights) suppressed weeds in chile pepper. In 2020–21, the third termination (8 days before beet leafhopper flights) yielded the maximum cover crop biomass (591 g⋅m−2) and greatest sinigrin addition to soil (213 mmol⋅m−2), and it was the only treatment that suppressed weeds. No cover crop treatment reduced hand-hoeing times. These results indicate that overwinter mustard cover crops can be ended to evade beet leafhopper flights and suppress weeds in chile pepper.
Consumers have become increasingly concerned about the environmental standards of industries from which they purchase products. Because consumers’ environmental concerns are increasingly becoming part of their purchasing decisions, industries have begun to restructure their business model to one that is more environmentally sustainable. Studies have indicated consumers’ actions and motivations for purchasing sustainable products vary based on consumer demographics. The main purpose of this study was to compare the differences in consumers’ perceptions and willingness to pay as they relate to retail floral providers’ sustainable and environmentally sound practices based on demographic traits. A total of 2172 people responded to an online survey. The sample used in this study was a random selection of individuals 18 years of age or older living in the United States. Survey responses were collected from 21 Dec 2022 to 27 Jan 2023. Data were analyzed using analyses of variance and post hoc tests as well as descriptive and frequency statistics. Results indicated there was a difference in the way respondents answered the survey questions based on demographics. Respondents 34 years of age or younger with college experience indicated the most willingness to make purchases and pay premiums from floral providers that incorporate sustainable attributes into their business model. Males indicated a stronger willingness to shop at a floral provider based on several of the environmental statements when compared with other genders. The results provide evidence of the value of the integration of sustainability practices into the business model of floral providers to make it more competitive.
According to the 2021 Extension Master Gardener (EMG) National Summary, the EMG Volunteer Program had an estimated 84,700 volunteers throughout the United States. These volunteers helped communities garden and grow food, provided opportunities to engage in activities that improved physical and mental health, and worked on projects that addressed environmental issues. In total, these programs contributed 3.1 million hours of education to local communities and $88 million dollars in value to the public. However, the COVID-19 pandemic presented challenges for the program, with many states implementing reduced requirements and increased flexibility for volunteers. The workshop “Dynamic Volunteer Engagement and Impactful Educational Outreach Taking Us Into the Next 50 Years of the EMG Program” at the 2022 ASHS conference discussed how to engage EMG volunteers despite the limitations of limited in-person contact. The workshop featured three Extension educators and EMG coordinators who shared their experiences and strategies for engaging volunteers during the pandemic. Topics discussed included engaging volunteers in local food systems and community gardens, engaging students in horticulture at an earlier age, and digital volunteer opportunities. Overall, the workshop provided valuable insights and facilitated discussions on how to adapt and continue the EMG program during challenging times.