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Open access

Sabahudin Hadrović, Filip Jovanović, Sonja Braunović, Tatjana Ćirković Mitrović, Ljubinko Rakonjac, Mersida Jandrić, and Dina Hadrović

To select softwood broadleaves for biomass cropping, a study of the carbon and nitrogen content of the bark and wood of six softwood broadleaves in southwestern Serbia was conducted. Compared with white willow, european aspen, common alder, black poplar, and silver birch, goat willow has a high potential for carbon storage in bark and wood, representing a promising softwood broadleaf for biomass production.

Open access

Suzette P. Galinato, Aidan Kendall, and Carol A. Miles

Growers need reliable information on costs and returns they can expect for a cider apple (Malus ×domestica) orchard suitable for mechanization because specialty cider apples can only be used for making cider, and returns are expected to be lower than for fresh table apples. This study estimates the costs, returns, and net profit that growers may realize by planting cider apples in either a freestanding or tall spindle system that use a mechanical harvester (both systems) and mechanical hedger (tall spindle system only). Results show that both production systems have positive net returns during full production, and their respective break-even returns are lower than the current market price, demonstrating that both systems are potentially profitable investments. Results also show that the tall spindle system is potentially more profitable due to the advantages of earlier start of fruiting and higher crop yield. The estimated net returns of the tall spindle system during full production are nearly 4 times higher than that of a freestanding system. At a discount rate of 10%, the net present value (NPV) of the tall spindle system is positive and payback period is 13 years, whereas the NPV of the freestanding system is negative. The discount rate represents the time value of money and reflects the perception of risk for the investment. The break-even discount rates (i.e., NPV = 0) are ≈6.88% for the freestanding system and 10.78% for the tall spindle system. Sensitivity scenarios found that when all else was constant, profitability increased as market price, crop yield, and production area increase and also when the cost of the harvester decreased. Because mechanical harvesters are expensive, profitability tends to be more favorable for larger farms due to economies of scale. Also, a high picking efficiency is important because fruit that falls on the ground is considered crop yield loss and reduces the gross income from cider apples.

Open access

Rongrong Duan, Deke Xing, Tian Chen, and Yanyou Wu

High- and low-affinity transport systems are the main pathways for the transportation of NO3 and NH4 + across intracellular membranes. NO3 and NH4 + are assimilated through different metabolic pathways in plants. Fifteen ATP molecules are hydrolyzed in the metabolic process of NO3 ; however, only five ATP molecules are hydrolyzed in that of NH4 +. In this research, seedlings of Iris pseudacorus and Iris japonica were used as the experimental materials in the NO3 :NH4 + = 30:0, NO3 :NH4 + = 28:2, NO3 :NH4 + = 27:3, NO3 :NH4 + = 15:15, NO3 :NH4 + = 3:27, and NO3 :NH4 + = 0:30 treatments at the 7.5 mmol·L−1 the total nitrogen content (TN). The intracellular free energy was represented by physiological resistance (R) and physiological impedance (Z) according to the Nernst equation and could conveniently and comprehensively determine the cellular metabolic energy (GB). The maximum absorption rate (Vmax) and Michaelis constant (Km) for NH4 + and NO3 uptake were calculated according to the kinetic equation. The results showed that the cellular metabolic energy (GB) of I. pseudacorus was 1 to 1.5 times lower than that of I. japonica at each treatment on the 10th day. The GB values of I. pseudacorus and I. japonica seedlings increased with increasing NH4 + concentration. However, there was a turning point at the NO3 :NH4 + = 15:15 treatment for the cellular metabolic energy of I. pseudacorus and I. japonica. Correlation analysis showed that the value of cellular metabolic energy was negatively correlated with the Vmax and Km for NO3 uptake, whereas it was positively correlated with that for NH4 + uptake. These results demonstrate that the NO3 :NH4 + = 27:3 treatment level was the most suitable for I. pseudacorus and I. japonica. This indicates that the greater cellular metabolic energy is the most suitable for plant growth when the concentration of ammonium or nitrate had no significant difference at treatment. These results provide a simple and rapid solution for removal of nitrogen by determination of cellular metabolic energy.

Open access

Charles F. Forney, Kristen Cue, and Sherry Fillmore

The protrusion of sprouts is a major cause of loss of dry onions (Allium cepa L.) during extended storage. Sprouting is conventionally suppressed by treating onions with maleic hydrazide (MH) before harvest. More recently, ethylene was reported to inhibit sprout growth in stored onions, but commercial use of ethylene has been limited. Therefore, the objective of this study was to assess the effectiveness of ethylene on sprout suppression of five commercial cultivars of onions during storage and compare its effectiveness with and without MH treatment. Onions treated with MH were stored for up to 9 months at 1 °C in atmospheres with and without ethylene in a series of experiments conducted over six seasons. Differences in sprout elongation and protrusion were observed during storage in air among the five cultivars. Storage in ethylene was effective in inhibiting sprout elongation and root growth of onion bulbs in all cultivars, with concentrations of 7 µL·L−1 ethylene being more effective than 1 µL·L−1 ethylene. Delaying application of ethylene by 4 months was less effective in inhibiting sprout elongation than continuous treatment. Ethylene provided greater sprout suppression than MH treatments alone and could serve as a replacement for MH.

Open access

Phillip A. Wadl, Livy H. Williams III, Matthew I. Horry, and Brian K. Ward

The yield and insect resistance of 12 sweetpotato (Ipomoea batatas) clones grown in two different production systems (organic black plastic mulch and conventional bare ground) were evaluated in 2016 and 2017 in coastal South Carolina. Significant differences in total storage root yield, marketable storage root yield, U.S. No. 1 storage root yield, and percent of U.S. No. 1 storage roots in all trials were found, except for percent of U.S. No. 1 storage roots in 2017 for the organic black plastic mulch trial. In the organic black plastic mulch trials, ‘Bonita’ and USDA-04-136 consistently produced high marketable yields, whereas ‘Ruddy’ and USDA-W388 consistently produced the lowest marketable yields. ‘Averre’, ‘Beauregard’, ‘Covington’, and USDA-09-130 exhibited variable performance, with marketable yields among the highest in a single year. For the conventional trials, USDA-04-136 consistently produced high marketable yields, whereas ‘Ruddy’ and USDA-W-388 consistently produced the lowest marketable yields. ‘Averre’, ‘Bonita’, ‘Covington’, and USDA-09-130 exhibited variable performance, with marketable yields among the highest in a single year. For the organic black plastic mulch, significant differences were detected in the percent of uninjured roots and percent white grub (primarily Plectris aliena) damage in 2016 and in wireworm (Elateridae)-cucumber beetle (Diabrotica)-flea beetle (Systena) severity index (WDS severity index) in 2016 and 2017. USDA-04-136 and USDA-W-388 consistently had the lowest WDS severity index, whereas ‘Covington’ consistently had the highest WDS severity index. For the conventional trials, significant differences were found among clones in both years for all insect rating variables, except for percent sweetpotato weevil (Cylas formicarius elegantulus) damage. ‘Ruddy’, USDA-04-136, and USDA-W-388 consistently yielded the highest percent of uninjured roots, whereas ‘Averre’, ‘Bonita’, SC-1149-19, and USDA-09-130 consistently had the lowest percent of uninjured roots. The research reported here for yield and insect resistance under conventional and organic production systems will be useful for producers in the selection of cultivars suitable for growth in South Carolina.

Open access

Zhanao Deng, Natalia A. Peres, and Johan Desaeger

Caladiums (Caladium ×hortulanum Birdsey, Araceae Juss.) are ornamental aroids often used as container or landscape plants (Evans et al., 1992). They are valued for their variably shaped, bright foliage. Most commercial caladium plants are produced by forcing tubers in containers. Florida growers produce essentially all the caladium tubers used in the United States and in the world for pot plant production and tuber sales (Bell et al., 1998; Deng et al., 2008b). Roughly, two-thirds of Florida-produced caladium tubers are used to produce pot plants, and one-third are used for direct planting in the landscape.

Open access

F. Bailey Norwood

Gardening is a popular practice despite the abundant and affordable food at the grocery store, suggesting gardening is more than just a way to obtain food. The purpose of this article is to explore these other motivations. Evolutionary and pragmatic motivations are first explored, and then discarded, in favor of a values-driven approach. Gardening is depicted as both a form of art and a hobby. As an art form, the writings of iconic philosophers such as Immanuel Kant, Arthur Schopenhauer, and Martin Heidegger—as well as modern philosophers—are used to articulate the meaning of gardening as an aesthetic experience. As a hobby, gardening is a socially approved form of leisure and productive play. The conclusion is that, in addition to obvious physiological benefits such as food and exercise, gardening helps us acquire higher needs, such as self-actualization and transcendence. Why do we garden? No simple answer can suffice. Gardening, like many interests, is performed both for an end product and for the process itself. Gardeners can hardly be expected to be able to articulate their reasons, just as sports fans would have difficulty articulating why they watch football, or music lovers explaining why songs mesmerize them. When pressed, their answers will be mostly a tautology (e.g., I simply like it). However, this does not mean we cannot make progress in understanding the motivations for gardening. Gardening is a form of exercise, it is a hobby, and is performed for aesthetic pleasure, and research on motivations for all three of these exist—especially that regarding aesthetics.

Open access

Fekadu Fufa Dinssa, Ruth Minja, Thomas Kariuki, Omary Mbwambo, Roland Schafleitner, and Peter Hanson

Amaranths (Amaranthus sp.) are a popular leafy vegetable grown and consumed by resource-poor people in many African countries. Greater awareness of the importance of nutritious foods has increased demand by African consumers for amaranth. Presently, most African farmers grow low-yielding local varieties of variable seed quality. High-yielding amaranth varieties that are adapted to the major agro-ecologies of eastern and southern Africa possess key traits needed by male and female farmers and meet diverse market preferences are required. The objective of this study was to identify amaranth lines adapted to major amaranth production environments in Kenya and Tanzania using a gender-disaggregated farmers participatory approach to explore possible gender differences in trait and variety preferences. Twenty amaranth entries were evaluated for vegetable yield, agronomic traits, and organoleptic taste tests in replicated, farmer-participatory variety selection trials at one location in Kenya and at four locations in Tanzania. Differences among entries (G), locations (E), and G × E interaction were significant or highly significant for marketable vegetable yield. Location followed by entry was the most important factor that explained differences in yield. G and G × E interaction biplot analysis classified the five locations into two different mega-environments, mainly based on altitude, temperatures, and soil characteristics. Marketable vegetable yield was positively correlated with leaf length, plant height, and the selection scores of female and male farmers at almost all locations. Selection scores of female and male farmers were positively correlated, indicating that male and female farmers shared similar amaranth variety preferences. Farmers identified and ranked important traits that can be used by breeders to design amaranth product profiles and develop amaranth breeding objectives. Lines combining high yield with high farmer and consumer preference scores have been retained for distinctiveness, uniformity, and stability tests for possible release as commercial varieties.