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Open access

Mary Rogers, Illana Livstrom, Brandon Roiger and Amy Smith

Growing North Minneapolis (GNM) is an urban agriculture and youth development summer program sited in the North Minneapolis, MN, neighborhood. The program is a university–community partnership between faculty at the University of Minnesota (UMN) and North Minneapolis community partners. We leverage resources from the city of Minneapolis Step-Up program to recruit, train, and employ youth (14–15 years old) who face barriers to employment—particularly youth from low-income families, youth of color, youth from immigrant families, and youth with disabilities. Youth interns are placed in a 10-week-long summer program and are matched with undergraduate student mentors from the UMN and North Minneapolis gardener mentors. The undergraduate students and garden mentors work together to lead teams of youth and work in multiple urban garden sites located in North Minneapolis, a designated low-resource community in the metro area. One of our goals is to develop leadership experience for UMN undergraduate students and improve food and horticultural skills among urban youth through garden-based education. Learning is experiential and contextualized in the various community garden sites through activities focused on food justice and accessibility, food production systems, and horticultural science. Youth learning and development outcomes are reported based on written postprogram qualitative survey questions prompting youth to identify what they learned throughout the program, what they enjoyed the most, and what challenged them after the summer program in 2018. Our results show that youth participants learned across multiple domains of knowledge and valued the social interaction offered by the intergenerational mentorship structure. The GNM program can serve as a model for garden-based experiential learning with early high school youth.

Open access

Darren J. Hayes and Bryan J. Peterson

Several species of honeysuckle from Europe and Asia have proved to be invasive in North America, with substantial impacts on native ecosystems. Although shrubby honeysuckles of Eurasian origin have appeared on banned plant lists in North America and other parts of the world, cultivars of the edible blue honeysuckle (Lonicera caerulea L.) derived from Eurasian germplasm and marketed as honeyberry, Haskap, or sweetberry honeysuckle have recently been widely developed for agricultural use in North America, with little scrutiny of invasive potential in North America despite its documented invasion of the Scandinavian Peninsula in northern Europe. To gain insight into differences in growth strategies among congeners, we compared the growth of Eurasian L. caerulea with that of a closely related congener in North America [Lonicera villosa (Michx.) R. & S.] and two known invasive congeners from Eurasia (Lonicera tatarica L. and Lonicera xylosteum L.). In Expt. 1, L. villosa, L. caerulea, and L. tatarica were grown in #1 nursery containers after top-dressing with Osmocote Pro 17–5–11 4-month controlled-release fertilizer (CRF) at rates of 5, 10, 15, 20, and 25 g CRF/container. Across all fertilizer treatments, L. caerulea outperformed L. villosa by a factor of two for root and shoot dry weights, although L. tatarica produced more growth than either of the others and was more responsive to increasing CRF. However, L. caerulea more strongly resembled L. tatarica in form, producing leaves of greater individual size and producing significantly taller primary stems than L. villosa, evidence for prioritization of competitive growth. In Expt. 2, plants of the same taxa plus L. xylosteum were grown communally in #20 nursery containers, followed by a period in which each container was subjected to regular irrigation, withheld irrigation (dry treatment), or inundation (flooded treatment). Plant growth differed substantially among taxa, but moisture treatments did not affect growth significantly. As in Expt. 1, plants of L. caerulea in Expt. 2 produced greater dry biomass than plants of L. villosa and resembled the invasive Eurasian honeysuckles more strongly in size and form. We conclude Eurasian L. caerulea is distinct in growth rate and morphology from North American L. villosa. In light of these findings, the ecology and competitive ability of Eurasian L. caerulea may not be well predicted by ecological observations of its closely related North American congener.

Open access

Young-Sik Park, Sang-Hyun Lim and Jae-Yun Heo

Open access

Benjamin L. Campbell and William Steele

The number of pollinators has been reported to be decreasing for the past several decades. Numerous sources (e.g., climate change, pesticides, loss of habitat) have been noted as potential contributing factors to the decline. With respect to the green industry, the impact of pesticides on pollinator decline and consumer response to this impact is of critical importance. Although no definitive link exists of pesticides being a major contributing factor to pollinator decline, some retailers have banned their suppliers from using certain pesticides. As various sources (e.g., universities, media, activist groups) provide information (both positive, neutral, and negative) about the impact of pesticides on pollinators, no information exists regarding how consumers value such information. Using a sample of Connecticut consumers, this study evaluates how both information source and information type impact a consumer’s decision to purchase pollinator-friendly plants in the future. The study finds that consumers exposed to either neutral (no link between pesticides and pollinator decline) or negative (link between pesticides and pollinator decline) information from universities and major media outlets indicate they will purchase more pollinator-friendly plants compared with the no information (control) treatment. The results show that information from the federal government, nursery/greenhouse industry associations, and environmental activist groups have the same impact on self-reported future pollinator-friendly plant purchasing as the no information group.

Open access

Thibault Nordey, Elias Shem and Joel Huat

Numerous studies have highlighted the merits of grafting to improve the performance of vegetable crops. However, the technique is hindered by several obstacles, including the synchronization of seedlings used as scions and rootstocks, and the effects of rootstocks and climatic conditions on grafting success rates. This study sought to gain insights into how such technical obstacles affect tomato grafting. An initial experiment conducted in a greenhouse set out to assess the relevance of using degree-days to predict the growth rates of seedlings used for grafting (i.e., stem diameters above cotyledons). The success rate for grafting a tomato variety (Tanya) on 10 different rootstocks from different species—namely tomato, eggplant, african eggplant, and a wild species—was assessed at different temperatures (i.e., 15, 20, 25, 30, 35, and 40 °C). The effects of grafting on plant vigor (i.e., fresh biomass), number of leaves, and plant height, and on the hydraulic conductivity of xylem vessels in the plant stem were assessed 2 weeks after grafting. The results show the advantage of using degree-days to predict the ready-to-graft stage of seedlings, as it reduced the discrepancy among trials. The grafting success rate was more than 90% at 15 and 20 °C, but decreased significantly with higher temperatures, down to 20% at 40 °C. Larger variations in growth rate for seedlings used as scions and rootstocks, a lower grafting success rate, and less vigor were recorded for heterografted plants than for homografted plants. The lower hydraulic conductivity measured in the stems of grafted plants, especially heterografted plants, was consistent with the lower plant vigor observed. Further studies are needed to investigate how grafting affects the hydraulic conductivity of xylem vessels in later developmental stages of grafted plants.

Open access

Fengyun Zhao, Yu Jiang, Xiufeng He, Huaifeng Liu and Kun Yu

The use of water-soluble chemical fertilizers for years under drip irrigation conditions results in soil compaction, fertility decline, and fruit quality decrease in arid areas. Currently, little research has been reported regarding the effects of increasing organic fertilizer and reducing drip chemical fertilizer on the growth of grape plants under different conditions in arid areas. In this study, five different treatments were conducted. Compared with no fertilizer for 3 consecutive years (CK) and single fertilizer for 3 consecutive years (T0), organic fertilizer plus 1 year of reducing drip chemical fertilizer (T1), organic fertilizer plus 2 years of reducing drip chemical fertilizer (T2), and organic fertilizer plus 3 years of reducing drip chemical fertilizer (T3) improved the soil pH, electrical conductivity (EC) values, and soil organic matter content to different degrees during early growth stages (15 days after anthesis) and mature stages (75 days after anthesis). The available N, P, and K contents in the T1 and T2 treatments increased significantly. With the T2 treatment, the longitudinal and transverse diameters of the ‘Summer Black’ grapes were the largest during the two fruit expansion periods. The anthocyanin content of grape peel with the T2 treatment was 22.0% higher than that with the T0 treatment. The soluble solids, sugar–acid ratio, various sugar contents, vitamin C, and total phenol of the fruit increased significantly with the T2 treatment, indicating that the T2 treatment was best for promoting grape growth and fruit quality and that the T3 treatment was the second best.

Open access

Jacqueline Cormier, Robert Heyduck, Steven Guldan, Shengrui Yao, Dawn VanLeeuwen and Ivette Guzman

A decrease in available farmland worldwide has prompted interest in polyculture systems such as intercropping where two or more crops are grown simultaneously on the same land to increase the yield per farm area. In Alcalde, NM, a year-round intercropping system was designed to evaluate organically produced blackberry cultivars (Rubus, subgenus Rubus) and winter greens in a high tunnel over a 2-year period. Two floricane fruiting blackberry cultivars, Chester Thornless and Triple Crown, were grown intercropped with ‘Red Russian’ kale (Brassica napus) and ‘Bloomsdale’ spinach (Spinacia oleracea) in a high tunnel. In an adjacent field, the planting of blackberry was repeated with no winter intercrop and no high tunnel. Both cultivars of blackberry were harvested July to September, and fresh weights were measured to determine suitability to the intercropping system in the high tunnel. Both species of winter greens were harvested January to April, and fresh yield weights were measured to discern fitness as possible intercrops in this system. Row covers were used for kale and spinach, and air temperatures were monitored November to April inside the high tunnel. High tunnel temperatures were within acceptable ranges for the production of greens with the use of rowcovers. Yield data from this study indicates that ‘Triple Crown’ blackberry outperformed ‘Chester Thornless’ blackberry in both the high tunnel and field trials with significant difference in the second season. Additionally, blackberry yields from both cultivars were observed to be higher in the field than in the high tunnel for both years. High temperature damage to high tunnel berry canes was noticed for both cultivars, with observed yield decreases in the second year in the high tunnel. Overall, this study indicates that the phenology and climate needs of the two winter greens and blackberry cultivars were not compatible for sustaining year-round organic high tunnel production.

Open access

Sara Andrea Moran-Duran, Robert Paul Flynn, Richard Heerema and Dawn VanLeeuwen

In recent years, nickel (Ni) deficiency symptoms has been observed in commercial pecan [Carya illinoinensis (Wangenh.) K. Koch.] orchards in New Mexico. Nickel deficiency can cause a reduction in lignin formation, which could affect the risk for breakage on pecan tree shoots. Ni deficiency might furthermore disrupt ureide catabolism in pecan and, therefore, could negatively affect nitrogen (N) nutrition in the plant. The objective of this study was to identify the effects of Ni and N fertilizer applications, at two rates, on net photosynthesis (Pn), leaf greenness (SPAD), and branch lignin concentration in New Mexico’s nonbearing pecan trees. Sixty trees for year 2012 (Pawnee and Western cultivars) and 40 trees for year 2013 (Pawnee cultivar) were used at two New Mexico locations (Artesia and Las Cruces) to evaluate the effects of Ni and N on tree measures. Treatments were as follows: (1) High N plus Ni (+Ni); (2) Low N no Ni (−Ni); (3) High N −Ni; and (4) Low N +Ni. In 2012 and 2013, there was an increase in leaf greenness for each location and cultivar (tree group) through time (June to September). Photosynthesis measures in 2012 differed between tree group, time in the season, and N and Ni treatments. In 2013, Pn was influenced by tree group and time (P < 0.0001), but N and Ni interaction did not present a significant effect related to Ni benefits. Photosynthesis varied over time in 2012 and 2013, with an inconsistent pattern. In this study, Ni application at the high N rate had a negative effect on ‘Pawnee’ Pn early in the season at the Artesia site, but this application had a positive effect for ‘Western’ from Artesia at the low N level, also early in the season. Lignin content varied between tree groups only. The application of N and Ni did not affect lignin in pecan shoots. The results show an inconsistent pattern regarding the benefits of Ni on nonbearing pecan orchards for leaf greenness, Pn, and lignin content during the 2-year study. Future studies on Ni should focus on pecan trees exhibiting leaf Ni deficiency symptoms or on soils with less than 0.14 mg·kg−1 of DTPA extractable Ni, as well as the long-term effect of Ni on pecan growth and development to optimize the addition of Ni into an efficient fertilization program.

Open access

Filippo Sgroi, Enrica Donia, Mário Franco and Angelo Marcello Mineo

The agri-food sector has changed significantly over the years, moving from a simple production system to a more and more industrialized one. For agents/operators involved in this sector, ensuring product quality and environmental externalities has become the key point to gaining a competitive advantage. In this context, corporate social responsibility (CSR) fits perfectly. This study analyzes the influence of CSR practices on the economic performance of a random sample of 130 agri-food companies in Italy. The results of an analysis of multiple linear regression models show that the economic performance (measured through value added and income) of agri-food enterprises seems to be influenced statistically by workplace CSR practices. Analysis of another model, during which we studied the relationship between income and the CSR practices (independent variables), highlights that operating results (economic performance) can be improved by CSR practices regarding the workplace, environment, and local community. Thus, empirical evidence shows that some CSR practices have positive effects on economic performance, with several implications for theory and practice.

Open access

Péter Szabó, Barnabás Kovács and László Kocsis