Low Tunnels Research Articles

Anemone Cut Flower Timing, Yield, and Quality in a High-Elevation Field and High Tunnel

A narrow window of optimal spring temperatures limits anemone (Anemone coronaria L.) cut flower production in the US Intermountain West, where fall plantings risk winter injury and spring plantings are limited by summer dormancy. Regional management recommendations are needed to improve anemone harvest timing and yield for growers in USDA hardiness zones 6 and below (average annual minimum temperatures below −18 °C). The aim of this research was to optimize flower timing, yield, quality, and profitability in high tunnel and field production systems by evaluating planting dates, winter insulation, tuber preparation, and cultivar selection. High tunnel and field trials were conducted from fall 2020 to spring 2022 in North Logan, UT (41.767° N, −111.811° W, 1405 m elevation, USDA hardiness zone 5). Tubers were pre-sprouted or directly planted into a high tunnel (left bare or covered with low tunnels) or field (left bare or covered with mulch, a low tunnel, or mulch and a low tunnel) from November to April. Harvest began as early as 2 March in the high tunnel and 9 April in the field, with overall average marketable yields (stems per m2 ± SE) of 142 ± 7 in the high tunnel and 85 ± 4 in the field. Planting pre-sprouted tubers under low tunnels in the high tunnel in November delivered the earliest harvest (2 March), greatest marketable yield (280 stems per m2 ± 73 SE), and greatest net returns ($38 per m2). For November field plantings, insulation improved emergence by 75% and marketable yield by 77 stems per m2 ± 15 SE. Combining high tunnel and field production with the season advancement techniques of fall planting dates, low-cost insulation, and pre-sprouting resulted in high total yields in the Intermountain West compared to traditional industry recommendations.

The Extraction Method of Navigation Line for Cuttage and Film Covering Multi-Functional Machine for Low Tunnels

Aiming at the problem of low intelligence in the automatic navigation of the cuttage and film covering multi-functional machine for low tunnels, this study proposed a navigation line extraction method based on the improved YOLOv5s model, which can achieve the accurate extraction of navigation lines based on two planting methods of seedling transplanting and direct seeding. Firstly, we pre-processed the acquired images using inverse perspective transformation. Next, the Coordinate Attention and Ghost modules were applied to improve the YOLOv5s architecture, increasing the detection accuracy and speed of field targets. Finally, we extracted the feature points and fit the navigation lines based on the shape features of the targets using the geometric method. The experimental results showed that, compared with other algorithms, the accuracy of the proposed algorithm could reach more than 96%, the accuracy of navigation line extraction reached 98%, and the average detection time was 51 ms. The proposed method was robust and universal, and it can provide reliable navigation paths for the cuttage and film covering multi-functional machine.

Overwintering Improves Ranunculus Cut Flower Production in the US Intermountain West

Ranunculus (Ranunculus asiaticus L.) cut flower production in the US Intermountain West is limited by a narrow window of optimal temperature ranges in the spring. With the increasing number of Intermountain West cut flower growers, regional management recommendations are needed to improve ranunculus harvest timing and yield. The objectives of this research were to evaluate planting dates, winter insulation, tuberous root (TR) preparation, and cultivar selection for flower timing, yield, quality, and profitability in high tunnel and field production systems. Trials were conducted in a North Logan, UT (41.7665° N, −111.811° W, 1405 m elevation, USDA hardiness zone 5) high tunnel and field from fall 2019 to spring 2022. TRs were either pre-sprouted or directly planted into a high tunnel (left bare or covered with low tunnels) or field (left bare or covered with mulch, a low tunnel, or mulch and a low tunnel) from November to April. High tunnels advanced production by four weeks, nearly doubled total yield, and increased the proportion of quality (longer than 25 cm) stems by 50% compared to the field. Planting pre-sprouted TRs in the high tunnel in November delivered the earliest harvest (6 Apr.), highest marketable yield (286 stems per m2 ± 36 SE), and highest net returns ($54 per m2), with 39% greater marketable yield for ‘LaBelle’ than ‘Amandine.’ Insulation nearly doubled emergence and improved marketable yield by 49 stems per m2 ± 8 SE for November field plantings. Ranunculus production was optimized as a fall-planted high tunnel crop in the Intermountain West but may be fall-planted in the field with insulation, allowing growers to maximize production during more optimal, early-season temperatures.

Mitigate the reverse effects of frost by cultivate tomato plants under different types of mesh cover for low tunnels

Tomato plants are highly sensitive to chilling stress so this experiment was conducted during successive winter seasons of 2020/2021 and 2021/2022 to investigate the possibility of sustaining production and quality of tomato yield under cold conditions by using different types of mesh cover for low tunnels. Two commercial cultivars, i.e., Super gold F1 and Super streen F1 were used. Seedlings were transplanted under different types of mesh cover for low tunnels. Three types of mesh cover (63%, 65%, 73%) had done to cover the plants of all tested seasons compared to open field condition (control "Without cover"). Results show that significant differences were observed among the two hybrid varieties of tomato studied, in terms of their vegetative growth characteristics (plant height, number of branches, number of leaves, fresh weight, dry weight and leaves area) as well as yield and fruit quality characteristics (Fruit set, total yield, firmness, T.S.S and Vit. C. ‘Super gold’ exhibited significantly higher values for these characteristics, compared to ‘Super strain B’. Chilling reduced the growth parameters (plant height, number of leaves, number of branches, plant fresh weight, plant dry weight) for control plants (without cover) compared to the coverage treatments (63%, 65%, 73%). Significant highest results in the growth, chemical composition of tomato leaves as well as yield and fruit quality parameters were obtained with covering tomato plants by white mesh cover 63% flowed by 65% of treatments which were best than the chilled plants. Concerning the interaction between hybrid varieties and covering treatments, it can be noticed that Cv. Super gold F1 which grown under white mesh cover 63% recorded a highly significant increases in plant height, number of branches, number of leaves, fresh weight, dry weight, leaves area, N, P, K, total chlorophyll, total proline, total sugers contents, fruit set, total yield, firmness, T.S.S and Vit. C. when compared to Cv. Super streen B F1 which grown in open field (without coverage).

The effect of UVB-blocking plastics on the efficacy of Beauveria bassiana and a conventional product against Lygus lineolaris on low tunnel strawberry.

Effective, safe and practical biocontrol options are greatly needed for combating Lygus lineolaris on protected culture strawberry. This study demonstrated how ultaviolet (UV)-selective plastics can improve the efficacy of the fungal biocontrol agent Beauveria bassiana (Mycotrol) compared to the conventional insecticide acetamiprid (Assail) against L. lineolaris on low tunnel strawberry. We found that UVB-blocking treatments improved B. bassiana spore viability in both in vitro and in vivo laboratory experiments. In the field, survival of Mycotrol-treated sentinel L. lineolaris was lowest under UVB-blocking low tunnels, but this did not translate into significant differences among covering treatments in local L. lineolaris density or fruit damage. In contrast, applying the product Assail resulted in the lowest L. lineolaris density and highest quality yield compared to Mycotrol sprays. This was especially pronounced under low tunnels of any UV-limiting plastic. This study indicates that growing under low tunnels is a useful tool to improve the efficacy of conventional products and biopesticides containing microbial biocontrol agents. The efficacy of both products was improved under low tunnels, and specifically under UVB-blocking plastics for Mycotrol containing B. bassiana. However, there was little evidence that UVB plastics resulted in lower L. lineolaris densities and proportion of damaged fruit for either product in the field. Therefore we conclude that growing under any plastic covering is likely to benefit growers, but the economic value of growing under UVB tunnels is unclear. © 2022 Society of Chemical Industry.

Effect of elemental and bentonite sulphur applications on some mechanical properties of different polyethylene covering materials

ABSTRACT This study investigated the effects of two different chemical products applied to the soil to on some mechanical properties of greenhouse cover materials produced by CO-EX techology with HALS UV and NIQ UV additives over a period of 12 months. The effects of chemical treatments on the covering materials were investigated in fourteen low tunnels under natural weathering conditions during their useful life. Also, the effects of sulphur products on the pH and electrical conductivity (EC) of the soil were investigated. Initial impact resistance of HALS UV and NIQ UV added PE films were determined as 685.0 and 811.7 g, respectively. Impact resistances of HALS UV and NIQ UV added PE films in bentonite sulphur applications decreased by 48.1% and 33.8%, whereas in elemental sulphur applications decreased by 62.0% and 51.6% after 12 months, respectively. Soil pH was reduced by all sulphur treatments in compared to the initial value.

Influence of planting time and mulching on yield and quality of direct sown muskmelon (Cucumis melo L.) under low tunnel

An investigation was undertaken to study the impact ofdate of sowing and mulching under low tunnel conditionson the growth, yield and quality of direct sown muskmelonduring 2019-20 and 2020-21 at Vegetable Research Farm andBiochemical Laboratory of Punjab Agricultural University,Ludhiana. Treatments were comprised of four dates ofsowing (15th November, 15th December, 15th January underlow tunnels and 15th February in open conditions) and twomulch treatments (black polythene mulch and non-mulch).Muskmelon hybrid, MH-27 planted on 15th November gavehigher number of fruits (4.0), highest total yield (216.6 q/ha),ascorbic acid (22 mg/100g) and dry matter (8.6 %). 15th Januaryplanting gave highest vine length (186.8 cm), maximum fruitdiameter (17.6 cm), maximum fruit weight (830.3 g) and TSS(12 °Brix). Mulched plants exhibited better growth, yieldand quality when compared with non-mulch plants. It isconcluded that muskmelon sown under low tunnel on 15thNovember with black polythene mulch offers higher yieldand maximum net returns and B: C ratio.

Effect of low plastic tunnels, transplanting dates and mulching on quality of tomato (Solanum lycopersicum)

The present experiment was conducted at Research Farm and in Laboratory of the CCS Haryana AgriculturalUniversity, Hisar during spring summer 2014–15 and 2015–16 to study the influence of low plastic tunnels, transplanting dates and mulching on quality characteristics of tomato (Solanum lycopersicum L.). The treatments comprise two types tunnels, three transplanting dates and three types mulching materials which were laid out in factorial RBD design with three replications. Results of the study showed that pericarp thickness (3.02 mm), acidity (0.48%), ascorbic acid (26.61 mg/100 g) and TSS (5.68%) content in tomato fruits were recorded significantly higher when seedlings were transplanted under low plastic tunnel on 30 November using black polyethylene as mulch materials compared to other treatments. Moreover fruit firmness (4.66 kg/cm) was recorded significantly higher value when seedlings were transplanted under plastic low tunnel on 20 December with black polyethylene mulch during both the years.

Production, chemical components, and content of bioactive compounds of strawberry cultivars

There are only a few strawberry cultivars available in Brazil and all are imported from North America and Europe. Thus, the introduction of new materials and their evaluation under Brazilian environmental conditions is imperative. The objective of this study was to evaluate the production, chemical components, and concentration of bioactive compounds in strawberry cultivars under edaphoclimatic conditions in the municipality of Pelotas-RS. The experiment was conducted in the field with low tunnels in 2011 and 2012. The experiment in the field was arranged in a completely randomized design, with eight treatments (cultivars), four replications. Each plot consisted of nine plants. The experiment in laboratory was arranged in a completely randomized 8x3 factorial design (8 cultivars and 3 months of harvest) and 4 replications. The variables analyzed were fruit number and fruit mass per plant, production, yield, soluble solid content, titratable acidity, ascorbic acid, anthocyanins, phenolic compounds, and antioxidant activity. Cultivar and harvest month influenced acidity, and the contents of soluble solids, ascorbic acid, and bioactive compounds. Cultivar Camarosa showed higher production, and higher contents of anthocyanin, phenolic compounds, and soluble solids. Cultivars ‘Palomar and ‘Aromas’ stand out for the content of ascorbic acid.

Impact of Alternative Solid Media on Yield and Quality of Tomato Growing under Low plastic Tunnels

Impact of Alternative Solid Media on Yield and Quality of Tomato Growing under Low plastic Tunnels

The low acoustic noise and turbulence wind tunnel of the University of Sao Paulo

AbstractThis paper introduces the Low Acoustic Noise and Turbulence (LANT) wind tunnel of the Sao Carlos School of Engineering, University of Sao Paulo (USP-EESC), Brazil. The closed-loop wind tunnel features several devices to improve flow uniformity, reduce swirl, and lower the background acoustic noise and turbulence, enabling stability and aeroacoustic experiments. The design criteria was based on the best practices reported, in particular for low turbulence wind tunnels. Yet, these criteria are conflicting and we discuss the decisions that had to be made and present flow quality results that were achieved. The 16-bladed axial fan with 13-blade stators is driven by a variable-speed electric motor. At the corners, 100 mm dense acoustic foam is installed on the vertical walls, floor and ceiling, and the turning vanes are filled with acoustic-absorbing material. The long settling chamber contains a 3.175 mm mesh hexagonal honeycomb and five fine mesh nylon screens, ending in a 7:1 area ratio short contraction. The 3-m long closed-working section has a $1\times 1\ {\rm m}^2$ cross-section area. At 15 m/s the working section wall boundary layer is less than 100 mm thick, providing an area of at least $800\times 800\ \mathrm{mm}^2$ where the streamwise flow uniformity was within 1%. In the 10–30 m/s flow speed range, the turbulence intensity ranged from 0.05% to 0.071% and the background acoustic noise level, obtained with an inflow microphone, ranged from 90 and 110 dB. A benchmark experiment on a flat plate boundary layer produced an almost perfect two-dimensional Blasius profile up to $Re_x \approx 2.5 \times 10^6$ . A beamforming benchmark experiment on aeroacoustics accurately identified the sound emitted by a cylinder immersed in the flow.

Low Tunnels inside Mediterranean Greenhouses: Effects on Air/Soil Temperature and Humidity

The main objective of this work was to analyze the microclimate generated inside a low tunnel (floating row cover) installed in an Almería-type greenhouse. Low tunnels are commonly used in the open field to protect plants against insect attack and to improve the production of muskmelon and strawberry. Floating row covers can also be used inside greenhouses during the first few weeks after the transplantation of muskmelon and watermelon crops in spring-summer cycles. This work was carried out during the first weeks of a watermelon culture (Citrullus lanatus Thunb.) growing with a polyethylene row cover inside an Almería-type greenhouse (2115 m2). Air temperature and humidity, plant temperature and soil temperature and humidity were measured in the greenhouse inside and outside the row covers. During the three days of measurement, all greenhouse vent openings were closed. The use of the low tunnels increased average air temperature around plants from 24.0 ± 9.0 °C to 26.9 ± 9.7 °C. A maximum difference in air temperature of about 5.9 °C was observed at noon. The average daily temperature of the crop was 28.2 ± 11.8 °C inside the row cover and 24.6 ± 8.9 °C without it. Similarly, the absolute humidity of air was clearly higher inside the low tunnel (0.0201 ± 0.0098 g/g) than around the plant rows without floating cover (0.0131 ± 0.0048 g/g). The soil temperature was also higher inside the low tunnel compared to the area without this second plastic cover. The effect of the tunnel decreased with depth, with average temperature differences of 1.2 ± 0.5 °C on the soil surface and 0.6 ± 0.5 °C at 20 cm depth.

The effect of plastic low tunnels on natural enemies and pollinators in New York strawberry

Although growing strawberries under low tunnels is increasing in popularity across the northeastern United States, little is known of how they impact the presence of natural enemies and pollinators that provide key ecosystem services on strawberry. We employed passive (fruit collections, sticky cards and pitfall traps) and direct (direct observations, leaf brushing and fruit bagging) monitoring over 2–3 growing seasons to compare the abundance and impact of beneficial insects and mites on strawberry grown under low tunnels versus the open field. Three different low tunnel plastics ranging in UV-selectivity were included to determine any effect of UV exclusion on natural enemy and pollinator presence. Plant yield and fruit marketability was higher under low tunnels compared to the open field for two of three years observed. The abundance of predators, and to a lesser extent parasitoids, was similar or higher under low tunnels compared to the open field. However, catch on sticky cards revealed lower densities of parasitoids under tunnels. There was some evidence that UV-selecting plastics resulted in poorly pollinated fruit compared to UV-transmitting and open-field treatments. However, there was no difference in pollinator presence among treatments, so the mechanisms causing the plastic effect are unclear. Overall, we conclude that growing strawberries under low tunnels, regardless of UV selectively, can support higher and more marketable yield in some years while likely having neutral to positive impacts on beneficial predators, parasitoids and pollinators.

Albion Strawberry Responds to Mulch Treatments and Low Tunnels Covered with Photoselective Films

The impact of photoselective films on strawberry plants in a low tunnel system has not been well investigated in the northeastern United States, nor have there been studies looking at the effect of mulch color in a plasticulture system. During two separate years (2016 and 2017), we evaluated ‘Albion’ in an annual system with three ground mulch treatments (black plastic, white-on-black plastic, and no plastic) and under six cover treatments. Five of the cover treatments were low tunnel films that varied in their ultraviolet, photosynthetically active, and near-infrared radiation transmission profiles: Tufflite IVTM (TIV), KoolLite Plus (KLP), Trioplast (TRP), and custom-manufactured UV-transparent (UVT) and UV-blocking (UVO) films. The sixth cover treatment was the traditional open bed environment (no low tunnel). ‘Albion’ produced fruit for 18 to 19 continuous weeks during both years until as late as Thanksgiving (24 Nov.) in 2016. Overall, the average marketable yield was greater in 2017 (486 g/plant) than in 2016 (350 g/plant), and it was greater on black mulch than on no mulch (445 vs. 380 g/plant, respectively); white mulch was intermediate (419 g/plant) (P ≤ 0.05). There was not a significant increase in marketable yield under low tunnels compared with open beds. The average fruit mass was greater under KLP and UVO than open beds (TIV and UVT were intermediate), and greater on beds with no mulch than black mulch (white mulch was intermediate). Across cover treatments, plants on black mulch produced more runners than plants on white or no mulch, and the black mulch/open bed treatment generated the greatest number of runners in both years, more than double most other treatments in 2016. The present study demonstrates that mulch selection is important for maximizing the yield of ‘Albion’ in the Northeast region, and that both mulch and cover impact runnering and fruit size. For plant propagators producing ‘Albion’ tips in a field environment, the results of this study suggest they are likely to maximize runner quantity by cultivating plants on black mulch without low tunnel cover.

Growing Saffron Crocus in the Northeastern United States: Effects of Winter Protection and Planting Density

Saffron is well known as the most expensive spice in the world by weight. It is the dried stigmas of the saffron crocus (Crocus sativus). Besides being well known as a culinary spice, saffron is also important in the pharmaceutical, cosmetic, and dye industries. Saffron crocus is cultivated in a wide range of environments, from the Mediterranean to the Middle East, and even to northern India’s subtropical climate. Saffron crocus is an environmentally friendly and low-input crop, making it a perfect match for low-input and organic farming, and sustainable agricultural systems. The objective of this study was to evaluate the possibility of producing saffron in New England. The study was conducted from Sept. 2017 to Dec. 2019 at the University of Rhode Island. Two different corm planting densities and two winter protection methods were evaluated. In 2018, corm planting density did not affect the number of flowers per unit area or total stigma yields, but flowers from the low-density plots produced significantly (P < 0.05) heavier pistils than flowers from the high-density plots. In 2019, planting density had no effect on flower number, stigma yield, or pistil dry weight. In 2018, flower number, stigma yield, and pistil dry weight were similar to subplots that had been covered with low tunnels the previous winter and subplots that had not been covered. However, in 2019, the plants in the subplots that remained exposed during the winter produced significantly more (P < 0.05) flowers than the plants in the subplots that were in low tunnels for the winter. Saffron yields followed the same pattern, with the unprotected subplots yielding 57% more than the protected subplots (P < 0.05). These data indicate that winter protection is not beneficial for saffron crocus production in Rhode Island. The use of winter protection increases production costs and can decrease yields.

CH-52: Chilli hybrid suitable for low tunnel cultivation

Chilli (Capsicum annuum L.) is an important spice-cumvegetablecrop of the family Solanaceae. India is thelargest producer, consumer and exporter of chillies inthe world. Generally, the transplanting of chilli is donein February-March in North Indian plains and crop endsby October-November. However, there are some areasin Punjab where the chilli crop is transplanted in midNovember under low tunnels to get early crop and thiscrop ends in June which is followed by late paddyvarieties/Basmati crop. Thus, two crops in a rotation ispracticed by transplanting chilli under low tunnel. Themajor bottleneck in this low tunnel cultivation is nonavailabilityof suitable variety/hybrid. Therefore

Estimation of irrigation water requirement of strawberry crop under polyhouse and shadenet house conditions

Strawberry is a commercial crop with high added value, which was extended to new cultivation zones of India.Therefore, it is important to know the suitability of climate condition for growing strawberry in Indian condition. Protected cultivation structures are used to cultivate crops under partial controlled climatic condition to get higher yield and better quality harvest. There are different kinds of protected cultivation structure normally adopted in India such as greenhouse, shadenet house and low tunnels. Exact of amount water and nutrients required to applied to get higher yield through minimizing loss of quality. The objective of the study is to assess the effect of protected cultivation structure on ambient temperature, relative humidity and crop water requirement of strawberry with drip irrigation system grown during winter season (November-February). Reference evapotranspiration was calculated using the FAO-56 Penman-Monteith equation considering the locally recorded weather parameters. Monthly average of daily reference evapotranspiration values are ranging between 1.3 to 3.3 mm day-1, 1.4 to 3.7 mm day-1 and 2.0 to 4.9 mm day-1 for polyhouse, shadenet house and open field, respectively. The total water requirement of drip irrigated straw berry in protected cultivation structure is reduced by about 35.2 % under polyhouse and 25.5 % under shade net house in comparison to open field cultivation.

Low tunnels with shading meshes: An alternative for the management of insect pests in kale cultivation

Kale (Brassica oleracea L. var. acephala) is one of the most cultivated leafy vegetables in Brazil. Abiotic and biotic factors can damage kale crops, reducing production and quality and making it impossible to market the product. Thus, because consumers demand sustainable production of food, the objective of this study was to evaluate the production of kale and the damage caused by pests of hybrid kale grown in different seasons and under different types of mesh. Two growing seasons, six growing environments and two kale hybrids were evaluated. The parameters evaluated were yield as measured by the total number of leaves, marketable leaves, and damaged leaves. The settlement of Myzus persicae and the damage caused by Plutella xylostella, Hellula undalis and Diabrotica speciosa were quantified. During the dry season, there was a lower yield per plant, but there was greater commercial production due to lower levels of insect infestation on plants. The use of nonwoven shade mesh reduced the damage from P. xylostella and D. speciosa on plants grown during the rainy season and reduced M. persicae during the dry season. However, cultivation under the protection of the organza fabric provided more effective protection against P. xylostella and D. speciosa, resulting in greater production of kale leaves.

Foundation enhancement for reducing tunnel-building seismic interaction on soft clay

Seismic tunnel-soil-building interaction in high plasticity soft clays can led to important ground motion variability that affect medium to low rise buildings located adjacent to the underground structure. This paper presents a numerical study aiming at establishing the performance of an enhanced foundation system to be used as a mean to reduce detrimental interaction and enhanced the seismic performance of mid to low buildings located nearby tunnels. Initially, interaction effects are revised considering the effect that frequency content, intensity, and strong ground motion duration have on the interplay between incoming seismic waves reflected in the tunnel, and the energy feeding back from the building swinging back and forth during a large earthquake. Series of three-dimensional finite difference models were developed. Seismic analyses considered both normal and subduction events with a return period of 250 years were carried out. Finally, the seismic performance of the enhanced foundation system was established. From the results gathered in here, it was clearly established the effectiveness of the proposed system to reduce both foundation ground motions and building seismic demand.

Effect of low poly tunnel on the yield and economics of bottle gourd

The main objective of Front Line Demonstrations (FLDs) is to demonstrate newly released crop production technologies and its management practices at the farmer’s field under different agro-climatic regions and farming situations. Realizing the importance of frontline demonstrations in transfer of off season production technologies in bottle gourd, Krishi Vigyan Kendra, Maulasar, Nagaur-II conducted FLDs at farmers’ field to assess the economic feasibility of technology. Result of a comparative evaluation of low poly tunnel technology and traditional growing method of bottle gourd showed that the average yield of demonstrations was found to be 298 q /ha, whereas, for local crop, it was found to be 245 q/ha. The gross returns (Rs. 238400/ha), net returns (Rs. 138200/ha) and BCR (2.38) ratio were also recorded highest in bottle gourd grown under low tunnel compared to local check. The total bottle gourd yield and net profit per unit area were above normal when grown under low tunnels as the produce reached the market early avoiding the market glut.