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.

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.

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.

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.

Winter Survival and Second-year Spring Yields of Day-neutral Strawberry Are Influenced by Cultivar and the Presence of Low Tunnels

Day-neutral (DN) strawberry (Fragaria ×ananassa) cultivars have potential to produce high yields in New England and greatly extend the period of regional strawberry production each year. However, DN strawberries have primarily been evaluated as an annual crop in cold climates; thus, winter hardiness and subsequent second-year spring yields are not well understood. Separate DN plantings were established as dormant bare-rooted plants in Durham, NH (U.S. Department of Agriculture hardiness zone 5b) in 2017 and 2018. During their first year of growth and fruit production, plants were grown under one of two cover treatments: a plastic-covered low tunnel or the traditional open field environment (open beds). In November, plants were covered with either straw much (Winter 2017–18) or rowcover (Winter 2018–19) for low-temperature protection during the winter months. In the spring of the second year when winter protection was removed, the same cover treatments (low tunnel or open bed) were re-administered to plants. Plant survival was affected by year and cultivar, with average survival rates of 82% and 98% in Spring 2018 and Spring 2019, respectively. Plant survival ranged from 34% (‘Monterey’) to 99% (‘Aromas’) in 2018, and 92% (‘Albion’) to 100% (‘San Andreas’ and ‘Seascape’) in 2019. Cultivar significantly affected total and marketable yields in both years, and marketable yields ranged from 35.8 to 167.3 g/plant in 2018 and 121.6 to 298.6 g/plant in 2019. The greatest marketable yields were produced by ‘Aromas’, ‘Cabrillo’, ‘San Andreas’, ‘Seascape’, and low-tunnel ‘Sweet Ann’. In 2019, ‘Cabrillo’, ‘San Andreas’, and ‘Seascape’ produced greater marketable yields during the 6-week second-year season than they had during the plants’ first year of fruit production the previous year, which spanned 18 weeks. Low tunnels hastened fruit ripening in the spring and result in earlier fruit harvests, and in 2019, marketable yields were significantly greater under low tunnels for the first 1 to 3 weeks, depending on cultivar. Total and marketable yields were unaffected by low tunnels in 2018, but were significantly greater under low tunnels in 2019. For cultivars in the 2019 experiment, the increase in marketable yield under low tunnels (compared with open beds) ranged from 92.3 to 166.5 g/plant, except for Sweet Ann, for which marketable yields were 256.6 g/plant greater under low tunnels than on open beds. Using a conservative direct market rate of $4.50/lb, the second-year spring yields produced in the present study had a direct market value of between $3899/ha and $95,647/ha, depending on cultivar and year. We demonstrate that it is not only possible to overwinter DN strawberry plants in northern New England, but that the second-year yield may even exceed first-year production. The results from the present study indicate great potential for profitability from an overwintered DN crop.