High tunnels are an increasingly popular part of the infrastructure among small and diversified farms that market their products directly to consumers. In addition to extending the growing season, research has strongly indicated that high tunnels can increase yield, enhance shelf life, and improve the quality of crops grown. The objective of this study was to gain a better understanding, from the perspective of farmers, of the challenges and opportunities associated with adopting high tunnels for specialty crops in Indiana. We collected information through a case study that included questionnaires and in-depth interviews with 20 farmers. We found that the additional labor and time requirements of high tunnel production, the increased complexity of high tunnel production, soil fertility, and disease management, and limited winter markets posed the greatest challenges. The ability to differentiate their products based on higher quality and longer shelf life, the ability to obtain a premium price, the ability to have a source of income during the off-season, and the ability to produce complementary crops were the most important opportunities for using high tunnels. This research implied ways to expand opportunities and reduce barriers to maximizing the potential of high tunnels. Understanding the human dimensions of managing high tunnels is important for providing extension educators and Natural Resources Conservation Service field staff with better knowledge of the common difficulties and benefits of this technology so they are better able to advise farmers considering investing in a high tunnel. A focus on the human dimensions is also helpful for identifying research priorities to evaluate new approaches to decreasing problems and increasing benefits. Consequently, this study provided an in-depth understanding of farm-level challenges associated with high tunnel adoption to improve future research in diverse fields.
You are looking at 21 - 30 of 27,904 items for
Analena B. Bruce, Elizabeth T. Maynard and James R. Farmer
Youngsuk Lee, Hun Joong Kweon, Moo-Yong Park and Dongyong Lee
Nutrient content assessment of plant tissues is widely performed by farmers to determine the appropriate amount of fertilization to use for their crops. A nondestructive leaf chlorophyll meter is one of the most commonly used devices for performing field assessments of the nutrient status of leaves. However, it is challenging to use a chlorophyll meter to assess the nutritional status of perennial plants, such as the apple (Malus ×domestica) tree, because of the difficulty estimating nitrogen (N) during the entire growing period. We compared the chlorophyll meter readings with leaf nutrient profiles collected from young ‘Arisoo’/M.9 apple trees throughout the growing period. A significant positive correlation between the chlorophyll meter readings and leaf N content was found from May to August during the midseason. Regression analysis indicated that the best sampling time for predicting the foliar N content of apple tress is from late June to late July. This result suggests that a reliable leaf N assessment can be performed in a rapid, nondestructive way in apple orchards.
Derald Harp, Gaye Hammond, David C. Zlesak, Greg Church, Mark Chamblee and Steve George
Landscaping today involves the struggle to balance aesthetically pleasing plants while minimizing the impact on the environment, reducing water usage, decreasing fertilizer use, and eliminating or significantly reducing pesticide usage. Roses (Rosa sp.), although seen as challenging plants, remain the most popular flowering shrub in the United States. The identification of new cultivars that combine beauty, pest and disease resistance, and drought tolerance are important to Texas landscapes. Sixty roses were assessed over a 3-year period to determine flowering, drought tolerance, disease resistance, and overall landscape performance in minimal-input gardens in north central Texas. Atypical weather during the study had a significant impact on performance. A 2-year drought (2010–11) was accompanied by the hottest summer on record (2011), which included a record number of days of at least 100 °F or higher. As a result, supplemental irrigation was provided three times both summers. Roses generally fared well under these conditions and survived the drought. Flowering was most abundant during the spring and fall, and it was least abundant in the summer. Powdery mildew [PM (Sphaerotheca pannosa var. rosae)] was a minor problem. Nine of 60 cultivars developed no visible symptoms of PM during the study. Most PM occurred in Spring 2010, with very little found after June; none was found in 2011. Black spot [BS (Diplocarpon rosae)] was serious for some cultivars, but most were BS-free; RADrazz (Knock Out®) and Lady Banks White had no observed BS during the study. BS occurred mostly in May, June, and November. Overall landscape performance ratings were high, with 23 cultivars having a mean landscape performance rating equal to or better than the Belinda’s Dream standard. The best-performing cultivars were RADrazz (Knock Out), RADcon (Pink Knock Out®), RADyod (Blushing Knock Out®), WEKcisbaco (Home Run®), and Alister Stella Gray. This study was able to identify many other highly performing roses in north central Texas.
Flavia T. Zambon, Davie M. Kadyampakeni and Jude W. Grosser
There is accumulating evidence that root system collapse is a primary symptom associated with Huanglongbing (HLB)-induced tree decline, especially for commercial sweet orange and grapefruit trees on Swingle and Carrizo rootstocks. Maintaining root health is imperative to keep trees productive in an HLB-endemic environment. Preliminary greenhouse and field studies have shown that HLB-impacted trees had secondary and micronutrient deficiencies that were much greater in the roots than in the leaves, and that treatments containing three-times the recommended dose of manganese (Mn) improved tree health and growth and increased feeder root density in greenhouse trees. These results suggested that trees in an HLB-endemic environment have higher specific micronutrient requirements than those currently recommended. To test this hypothesis, established Vernia sweet orange grafted onto rough lemon rootstock trees were divided into eight supplemental CRF nutrition treatments (including two-times and four-times the recommended doses of Mn and boron) using a randomized complete block design in a commercial grove in St. Cloud, FL. The following supplemental nutrition treatments were used: no extra nutrition (control); Harrell’s–St. Helena mix 0.9 kg per tree; Harrell’s with 32 g of Florikan polycoated sodium borate (PSB) per tree; Harrell’s with 90 g of TigerSul® Mn sulfate (MS) per tree; Harrell’s with 32 g of PSB and 90 g of MS per tree; 180 g of MS per tree; 64 g of PSB per tree; and 180 g of MS plus 64 g of PSB per tree applied every 6 months since Fall 2015. Leaf and soil nutritional analyses were performed in Mar. 2017, Sept. 2017, and May 2018; a quantitative polymerase chain reaction was performed for Candidatus Liberibacter asiaticus (CLas) titer estimation in Nov. 2017. Significantly higher cycle threshold (Ct) values indicating reduced CLas bacterial populations were observed in trees that received the higher doses of Mn, especially those receiving four-times the recommended dosage of Mn (180 g Mn). Many trees exhibited Ct values of 32 or more, indicating a nonactive infection. Fruit yields of these trees were also increased. No significant differences in juice characteristics, canopy volume, and trunk section area were found between control plants and plants treated with 180 g Mn. Soil and leaf nutrients B, K, Mn, and Zn were significantly different among treatments at various times during the study. Our results strongly suggest that overdoses of Mn can suppress CLas bacterial titers in sweet orange trees on rough lemon rootstock, thus providing a therapeutic effect that can help restore tree health and fruit yields. This response was not observed when Mn and B were combined in the overdose, suggesting an antagonistic effect from B on Mn metabolism. When an overdose of Mn is used, biological functions and tree tolerance lost due to nutritional imbalances caused by HLB might be restored. Further studies are needed to elucidate which metabolic pathways are altered by comparing overdosed and conventionally fertilized HLB-impacted trees and to determine if the observed therapeutic effects can be achieved in trees grafted to other important commercial rootstocks.
Rafael A. Muchanga, Toshiyuki Hirata and Hajime Araki
Cover crops and compost application may influence soil quality and productivity of fresh-market tomatoes. The effects of hairy vetch (HV) (Vicia villosa Roth) and livestock compost on soil C and N stocks, N availability, and tomato yield were evaluated for 2 years in a plastic high tunnel. Averaged across years, soil C and N stocks increased in plots incorporating hairy vetch and compost more than in plots with no hairy vetch and compost. When compared with baseline stocks (initial soil C and N stocks before the initiation of the examination), soil C stock increased by 3%, 2.8%, 2.6% in the HV treatment, the compost treatment, and the HV and compost treatment, respectively. In contrast, a 1.85% loss of soil C stock was observed in a no HV and no compost (bare) treatment. Soil N stocks increased in all treatments, with the greatest increase in the compost treatment (26%) and the lowest in the bare treatment (9.3%). Averaged across sampling dates, the HV treatment exhibited the greatest soil N availability and nitrate levels in leaf petiole in both years, whereas the bare treatment exhibited the lowest soil N availability and nitrate levels in leaf petiole. HV + compost and compost treatments showed a similar influence on soil N availability, but HV + compost exhibited greater nitrate levels in leaf petiole than the compost treatment. The marketable and total yields were 10% to 15% greater in the HV and the compost treatments than in the bare treatment. N uptake was 17% to 38% greater in the HV treatment than in the other treatments. Because of unstable cover crop production in the northern region, a combined application of cover crops and compost may be one of the best practices to compensate for low cover crop biomass production by increasing organic matter input to the soil, thereby improving soil quality and tomato yield.
Narinder P.S. Dhillon, Supannika Sanguansil, Supornpun Srimat, Suwannee Laenoi, Roland Schafleitner, Michel Pitrat and James D. McCreight
Cucurbit powdery mildew (CPM) caused by Podosphaera xanthii (Px) is an economically important disease of bitter gourd (BG; Momordica charantia) in Asia. High-level resistance to CPM is known in various BG accessions that have been used to develop BG breeding lines that originated in different countries. BG breeding lines THMC 113 (Belize), THMC 143 (India), THMC 153 (Thailand), THMC 167 (India), and THMC 170 (Taiwan) possess high-level resistance to BG Px race (BG-CPM), designated Mc-1 from a field at Kamphaeng Saen, Thailand, whereas THMC 144 (India) is susceptible. Our objective was to determine the inheritance of resistance to BG-CPM race Mc-1. To that end, THMC 144 (India) was crossed with the five resistant lines. The parents and their respective F1, F2, backcross progenies were evaluated for BG-CPM disease severity in inoculated field and growth chamber tests. Resistance to BG-CPM race Mc-1 in the five resistant lines was controlled by at least two independent, recessive genes. Intercrosses of the BG-CPM–resistant lines revealed allelic resistances in four of the breeding lines: THMC 113, THMC 153, THMC 167, and THMC 170. Resistance in THMC 143 was clearly non-allelic for resistance to BG-CPM with the other four BG-CPM–resistant lines.
Zhenhua Li, Yiling Liu and RenXiang Liu
Many methods have been proposed for the identification of seed maturity, and almost all of them need to be performed after seed harvest. In this study, a real-time quantitative method that can be performed during seed development was used by integrating multiple-capsule traits using a high-throughput screening (HTS) technique. Capsule color, shape, and density parameters can reflect seed development and maturity. During seed development, we observed a fast decrease in color parameters (R, G, and B) and water content, as well as an increase in temperature sensitivity; an initial rise followed by decline in shape parameters [length, width, minimum circumscribed circle (MCC) diameter, area] was also observed; as well as irregular differentiation of density parameters of the capsules. Correlation analysis showed a significant relationship between seed maturity and capsule color, as well as its shape parameters (Table 1). In sum, our data demonstrate that that three-dimensional (3D) phenotypic platform can be used to differentiate seed maturity by quantitative evaluating multiple-capsule traits, which is a quantitative method for determining the maturity of seed while still growing in the fruit of the mother plant.
Cristian E. Loyola, John M. Dole and Rebecca Dunning
In the United States and Canada, there has been an increase in the demand for local specialty cut flowers and a corresponding increase in production. To assess the needs of the industry, we electronically surveyed 1098 cut flower producers and handlers in the United States and Canada regarding their current cut flower production and postharvest problems, and customer issues. We received a total of 210 responses, resulting in a 19% response rate. The results showed that the main production problem was insect management; crop timing was the second most important problem and disease management was the third. Crop timing encompasses a range of related issues such as determining the correct harvest stage, harvest windows that are too short, flowering all at once, or lack of control when the crop is ready to harvest. The main postharvest problems were temperature management, hydration, and flower food management. Timing and stem length were the two most mentioned species-specific production issues, with each one listed by 10% or more of the respondents for eight of the total 31 species. Regarding on-farm postharvest handling, hydration and vase life were the two most mentioned issues; they were reported for five and three species, respectively. For postharvest during storage and transport, damage and hydration were the most common issues; these were listed for three species each. The most commonly mentioned customer complaints were vase life and shattering, which were reported for six and two species, respectively. These results will allow researchers and businesses to focus on the major cut flower production and postharvest issues and on crops that are most in need of improvement in North America.
Zhuping Fan, Yike Gao, Ling Guo, Ying Cao, Rong Liu and Qixiang Zhang
Bearded iris (Iris ×hybrida Hort.) is a large horticultural hybrid complex in the Iris genus, and the lack of understanding about its inheritance laws has seriously hindered the breeding process. From parental bearded iris ‘Indian Chief’ and ‘Sugar Blues’, four hybrid populations—including F1, F2, BC1P1, and BC1P2—were generated through hybridization. Fifteen key phenotypic traits, including plant height (PH), scape height (SH), length of fall (LF), width of fall (WF), length of standard (LS), width of standard (WS), and so on, were measured, and several genetic parameters (e.g., trait variation, heritability, trait correlation, distribution of flower color) were analyzed. The variation of phenotypic traits indicated that the F1 generation could produce larger flowers and a greater number of blooming stems than other generations, whereas backcrossing was beneficial at producing more flowers on one scape in the offspring of ‘Indian Chief’ and ‘Sugar Blues’. WF had the greatest broad-sense heritability (73.91%) among the 15 phenotypic traits, whereas the broad-sense heritability of SH was the lowest (2.06%). The correlation between a vegetative trait (PH) and a reproductive trait (WS) provided a path to early selection of germplasm. Furthermore, four important floral traits (LF, WF, LS, and WS) also correlated significantly to each other, thus simplifying the selection of larger flowers. Genes regulating fuchsia flower color were dominant over those for bluish purple flowers. Genetic effects of flower color in recurrent parents could be reinforced by backcrossing, thereby providing a potential way to modify flower color through hybridization.
Dario Mantovani, Adolfo Rosati and Domenico Perrone
The wild asparagus species Asparagus acutifolius L. is widespread in Mediterranean and subtropical environments, where its spears are consumed regularly. The species is known to have ecophysiologic plasticity, however there is no literature on this subject. This work aimed at assessing the photosynthetic characteristics of this wild species of asparagus, grown under full light (FL) and partial (i.e., about 40%) light (PL) conditions, and evaluating its ecophysiologic response to drought and temperature stress. The photosynthetic response to light of spears and of new cladodes (NC; current year) and old cladodes (OC; previous year) was measured using an infrared gas analyzer coupled with a climatized cuvette chamber. Cladodes net photosynthesis at high irradiance was also measured at varying air temperatures and decreasing soil water availability. Results indicate that developing spears were photosynthetically active with no difference between FL and PL treatments. Photosynthetic rates did not differ between NCs and OCs and were greater for FL cladodes, except at low irradiance. Well-watered plants were photosynthetically active from 0 to 45 °C, with a maximum photosynthetic rate of up to 9 µmol·m–2·s–1 at 30 °C and a decrease of about 60% at 45 °C. The species also demonstrated high tolerance to drought, with positive net photosynthesis even at predawn leaf water potential values of –2.4 MPa. Showing great ecophysiologic plasticity, this wild asparagus could be an interesting species in areas were conventional crop species are not profitable economically, or as an intercrop in agroforestry systems.