Journal articles: 'Greenhoure effect'

1

Lewis, R. P. W. "THE GREENHOUSE EFFECT AND GREENHOUSES: AN OVERLOOKED EXPERIMENT." Weather 47, no. 2 (February 1992): 68–70. http://dx.doi.org/10.1002/j.1477-8696.1992.tb05777.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Scarratt, J. B. "Greenhouse Managers: Beware Combustion Fumes in Container Greenhouses." Forestry Chronicle 61, no. 4 (August 1, 1985): 308–11. http://dx.doi.org/10.5558/tfc61308-4.

Full text

Abstract:

The combustion of fossil fuels produces a number of gases that can be phytotoxic to plants. Managers of container nurseries should be alert to the fact that entry of these combustion gases into the greenhouse environment can have serious effects upon tree seedlings. At high concentrations, seedlings may be severely damaged or killed outright. Chronic exposure to low levels of pollution can significantly reduce seedling growth even when no other visible symptoms are present. Careful design and layout of greenhouse facilities, and vigilance in the operation of heating equipment, generators and vehicles, are essential to avoid the risk of pollution damage. The effects of an incident in which jack pine (Pinus banksiana Lamb.) container stock was exposed to non-lethal concentrations of combustion gasses are described.

APA, Harvard, Vancouver, ISO, and other styles

3

Othman, B. A., and E. S. Kakey. "PESTICIDES BIOACCUMULATION AND THEIR SOIL POLLUTANT EFFECT." IRAQI JOURNAL OF AGRICULTURAL SCIENCES 52, no. 1 (February 24, 2021): 36–47. http://dx.doi.org/10.36103/ijas.v52i1.1234.

Full text

Abstract:

This study was aimed to investigate pesticides bioaccumulation and their soil pollutant effect. The experiment was included sixteen active greenhouses in Erbil plane, and conducted during September 2017 and March 2018. The present study revealed that the pesticides residue of pyridabine, thiamethoxam, abamectin and spirodiclofen were detected in greenhouse soil samples. The values of soil heavy metals contaminations factor (CF) revealed, that the studied greenhouse soil samples were ranged from low to very high contamination, while for pesticides were ranged from non to high contaminated. Soil pollution load index results supported that, the greenhouse soil was contaminated especially by Cr, Ni and Co. Pollution load index (PLI) was ranged from 7.751 to 0.303; supporting that the soils were contaminated in most sites. It could be concluded that, significant need for the development of pollution prevention and scientific strategies to reduce heavy metal pollution and pesticide accumulation residuals within greenhouses in Erbil plane.

APA, Harvard, Vancouver, ISO, and other styles

4

Alharbi, Abdulaziz R., Jouke Campen, Mohamed Sharaf, Feije De Zwart, Wim Voogt, Kess Scheffers, Ilias Tsafaras, et al. "DE EFFECT OF CLEAR AND DEFUSE GLASS COVERING MATERIALS ON FRUIT YIELD AND ENERGY EFFICIENCY OF GREENHOUSE CUCUMBER GROWN IN HOT CLIMATE." Acta Scientiarum Polonorum Hortorum Cultus 20, no. 3 (June 30, 2021): 37–44. http://dx.doi.org/10.24326/asphc.2021.3.4.

Full text

Abstract:

Using proper greenhouse covering materials can provide a suitable environment for plant growth in Saudi Arabia. The effects of three different greenhouse covering materials, clear glass, polycarbonate and diffuse tempered glass were used to evaluate its effect on cucumber productivity, water and energy use efficiency. Results show that either water or light use efficiency was higher in compartments covered with diffused or clear glass than polycarbonate compartment. Inconsequence, fruit yield of cucumber plants/m2 was significantly higher (58%) in clear and diffuse glass greenhouses as opposed to polycarbonate greenhouse. In term of the effect of cultivar or plant density, no significant differences on cucumber yield were found. Using of different covering materials did affect environmental data of greenhouses. Less light was transmitted through polycarbonate cover than clear or diffuse glass. The photosynthesis active radiation (P.A.R.) was 996, 1703, 1690 mol/m2/d, while the electricity consumption was 2.97, 3.44, and 2.88 kWh under polycarbonate, clear glass, and diffuse glass, respectively. Meanwhile, diffuse glass compartment revealed 16% lower of water consumption than other covering materials. In this respect, it could be concluded that using diffuse glass, as a greenhouse cover material, has a strong positive influence on crop productivity under Saudi Arabia climate.

APA, Harvard, Vancouver, ISO, and other styles

5

Rasheed, Na, Lee, Kim, and Lee. "Optimization of Greenhouse Thermal Screens for Maximized Energy Conservation." Energies 12, no. 19 (September 20, 2019): 3592. http://dx.doi.org/10.3390/en12193592.

Full text

Abstract:

In this work, we proposed a Building Energy Simulation (BES) dynamic climatic model of greenhouses by utilizing Transient System Simulation (TRNSYS 18) software to study the effect of use of different thermal screen materials and control strategies of thermal screens on heat energy requirement of greenhouses. Thermal properties of the most common greenhouse thermal screens were measured and used in the BES model. Nash-Sutcliffe efficiency coefficients of 0.84 and 0.78 showed good agreement between the computed and experimental results, thus the proposed model appears to be appropriate for performing greenhouse thermal simulations. The proposed model was used to evaluate the effects of different thermal screens including; Polyester, Luxous, Tempa, and Multi-layers, as well as to evaluate control strategies of greenhouse thermal screens, subjected to Daegu city, (latitude 35.53 °N, longitude 128.36 °E) South Korea winter season weather conditions. Obtained results show that the heating requirement of greenhouses with multi-layer night thermal screens was 20%, 5.4%, and 13.5%, less than the Polyester, Luxous, and Tempa screens respectively. Thus, our experiments confirm that the use of multi-layered thermal screen can reduce greenhouse heat energy requirement. Furthermore, screen-control with outside solar radiation at an optimum setpoint of 60 W·m−2 significantly influences the greenhouse’s energy conservation capacity, as it exhibited 699.5 MJ · m−2, the least energy demand of all strategies tested. Moreover, the proposed model allows dynamic simulation of greenhouse systems and enables researchers and farmers to evaluate different screens and screen control strategies that suit their investment capabilities and local weather conditions.

APA, Harvard, Vancouver, ISO, and other styles

6

Zagorska, V., A. Āboliņš, and A. Upītis. "Untraditional Solutions For The Usage Of Greenhouse Effect." Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference 1 (August 5, 2015): 246. http://dx.doi.org/10.17770/etr2011vol1.928.

Full text

Abstract:

The heat solar energy traditionally is used in greenhouses for ensuring optimal plant vegetation regime in our climatic conditions. Glass verandas built during last centuries at the south side of living houses and summer cottages are appreciated as original use of solar energy. Veranda as light and warm room was used for different household needs and also for social activities. Up-to-date materials and technologies proposes wide spectrum of innovative activities for greenhouses and conservatories. The variable amount of solar energy is possible to smooth out by using accumulation system. In the paper results from vegetable drying experiments are presented. In the research used products – carrots, dry matter of the product at the start 8.5%, chopped product – 9.9%, after desiccation – equilibrium moisture content 10 -11%. The experimental device placed in the room is simulating the processes, which would occur if we use greenhouse for product drying, accordingly making changes in the design of conventional greenhouses by separating drying section from growing section, supplying warm heated in the greenhouse upper layer air from the bottom by forcing it with axial ventilator, and accordingly choosing appropriate accumulation system for energy storage in case when outside air temperature drop occurs.

APA, Harvard, Vancouver, ISO, and other styles

7

Tjosvold, Steven A. "508 PB 254 EFFECT OF CARBON DIOXIDE ENRICHMENT ON PRODUCTION AND QUALITY OF GREENHOUSE `ROYALTY ROSES PRODUCED IN COASTAL CENTRAL CALIFORNIA." HortScience 29, no. 5 (May 1994): 504c—504. http://dx.doi.org/10.21273/hortsci.29.5.504c.

Full text

Abstract:

The atmosphere of commercial greenhouses were enriched to 1200 μl·1-1 carbon dioxide 1 hour before sunrise and maintained until ventilation was necessary to cool the greenhouse and again anytime the greenhouse vents were closed in the daytime. Enrichment was only possible, on average, for 5 daylight hours in the winter and less in the warmer months. In the first 10 month experiment, total production was not different in carbon dioxide enriched greenhouses. Stem lengths of harvested flowers were generally longer in the enriched greenhouses, particularly in the winter months. In the second 10 month experiment, total production was again not different in carbon dioxide enriched greenhouses, however, stem length was only slightly longer in the winter months. Dry weights of flower buds, stems and leaves increased slightly but only in winter months.

APA, Harvard, Vancouver, ISO, and other styles

8

Bezari, Salah, Sidi Mohammed El Amine Bekkouche, Ahmed Benchatti, Asma Adda, and Azzedine Boutelhig. "Effects of the Rock-Bed Heat Storage System on the Solar Greenhouse Microclimate." Instrumentation Mesure Métrologie 19, no. 6 (December 29, 2020): 471–79. http://dx.doi.org/10.18280/i2m.190608.

Full text

Abstract:

The Mediterranean area is characterized by intense radiation generating high temperatures during the day in the greenhouse and low temperatures during the night. The temperature gap problem between the daytime and the nocturnal period which characterizes the region requires the use of greenhouses with a thermal storage system. A greenhouse equipped with a sensible heat storage system using a rock-bed, was compared to a witness one, under the same climatic conditions. Measurements were performed on the microclimate parameters of both greenhouses, such as temperature and relative humidity. Our work is based on an experimental analysis of greenhouse microclimate and evaluating the evolution of temperature and relative humidity prevailing inside the greenhouse. It has been found that the system efficiency is improved due to the storing of heat in excess during the daytime. This stored energy is used during night. The main obtained results showed that the heat storage system allowed an increase in the air temperature up to 0.9℃ and a decrease of the relative humidity about 3.4% during the night compared to the witness greenhouse. The improvement in the heated greenhouse microclimate during night has a very positive impact on the quality of fruit and yield.

APA, Harvard, Vancouver, ISO, and other styles

9

Flohn, H., A. Kampala, R. Knoche, and H. Mächel. "Wasserdampf als ein Verstärker des Treibhauseffektes: Neue Aspekte." Meteorologische Zeitschrift 1, no. 2 (April 29, 1992): 122–38. http://dx.doi.org/10.1127/metz/1/1992/122.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Morandin, Lora A., Terence M. Laverty, Robert J. Gegear, and Peter G. Kevan. "Effect of greenhouse polyethelene covering on activity level and photo-response of bumble bees." Canadian Entomologist 134, no. 4 (August 2002): 539–49. http://dx.doi.org/10.4039/ent134539-4.

Full text

Abstract:

AbstractWe conducted laboratory experiments assessing the relationship between commercial greenhouse polyethylene coverings and bumble bee, Bombus impatiens Cresson (Hymenoptera: Apidae), activity and loss from ventilation systems. Bee activity was measured in four small greenhouses, each with a different polyethylene covering. Bee activity was quantified using photodiode tunnels mounted in the hive entrances. Contrary to commercial greenhouse experiments, there was no difference in bee activity based on covering type. There was a positive linear relationship between temperature in the experimental greenhouses and bee activity. The potential for bee loss through open ventilation systems for five covering types was quantified using a Y-maze decision box. Bees were more attracted to direct light than to light transmitted through ultraviolet (UV) blocking coverings, whereas bees were equally attracted to direct light as they were to UV-transmitting coverings. These experiments suggest that greenhouses with UV-transmitting plastics may result in less bee loss through ventilation systems.

APA, Harvard, Vancouver, ISO, and other styles

11

Severin, M., R. Fuß, R. Well, F. Garlipp, and H. Van den Weghe. "Soil, slurry and application effects on greenhouse gas emissions." Plant, Soil and Environment 61, No. 8 (June 6, 2016): 344–51. http://dx.doi.org/10.17221/21/2015-pse.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Papadopoulos, Athanasios P. "GREENHOUSE ENVIRONMENT OPTIMIZATION FOR SEEDLESS CUCUMBERS." HortScience 27, no. 6 (June 1992): 662c—662. http://dx.doi.org/10.21273/hortsci.27.6.662c.

Full text

Abstract:

The greenhouse cover has previously been shown to have large effects upon the greenhouse environment, crop productivity and energy use. However, in most cases, because of inadequate treatment replication, the extent of these effects has been impossible to quantify with confidence. In the fall of 1987, a new greenhouse complex of 9 mini greenhouses (6.4m × 7.2m, each) was constructed at the Harrow Research Station on the principles of the 3×3 Latin Square experimental design and with glass, double polyethylene film and double acrylic panel greenhouse covers as the three levels of treatment in the Latin Square. During the spring seasons of 1988 and 1990 the greenhouse cucumber cultivar Corona was cropped in rockwool in all 9 mini greenhouses, under 3 day air (DAT: 18°C, 21 °C and 24°C) and 3 night air temperatures (NAT: 16°C, 18°C and 20°C), superimposed across the rows and columns of greenhouses, respectively, to estimate yield and energy use response to DAT, NAT and greenhouse cover variation. Early marketable yield was highest at the 18/18 and 18/20°C DAT/NAT combinations and final marketable yield was highest at 18°C DAT regardless of NAT. Yield differences due to the greenhouse cover were insignificant. However, there were consistent differences in greenhouse air RH due to greenhouse cover (60%, 70% and 75% daily averages for glass, double polyethylene and double acrylic, respectively). Also, there were significant energy savings with the use of double polyethylene or double acrylic, as compared to glass greenhouse cover, and with low DAT and NAT (28%, 15% and 12% energy use reduction, respectively).

APA, Harvard, Vancouver, ISO, and other styles

13

Shi, Qiang, Yulei Pan, Beibei He, Huaiqun Zhu, Da Liu, Baoguo Shen, and Hanping Mao. "The Airflow Field Characteristics of UAV Flight in a Greenhouse." Agriculture 11, no. 7 (July 7, 2021): 634. http://dx.doi.org/10.3390/agriculture11070634.

Full text

Abstract:

The downwash airflow field of UAVs is insufficient under the dual influence of greenhouse structure and crop occlusion, and the distribution characteristics of the flight flow field of UAVs in greenhouses are unclear. In order to promote the application of UAVs in greenhouses, the flow field characteristics of UAVs in a greenhouse were studied herein. In a greenhouse containing tomato plants, a porous media model was used to simulate the obstacle effect of crops on the airflow. The multi-reference system model method was selected to solve the flow field of the UAV. Studies have shown that the airflow field generated by UAV flight in a greenhouse is mainly affected by the greenhouse structure. With the increase in UAV flight height, the ground effect of the downwash flow field weakened, and the flow field spread downward and around. The area affected by the flow field of the crops became larger, while the development of the crop convection field was less affected. The simulation was verified by experiments, and linear regression analysis was carried out between the experimental value and the simulation value. The experimental results were found to be in good agreement with the simulation results.

APA, Harvard, Vancouver, ISO, and other styles

14

Huang, Tao, Hongqiang Li, Guoqiang Zhang, and Feng Xu. "Experimental Study on Biomass Heating System in the Greenhouse: A Case Study in Xiangtan, China." Sustainability 12, no. 14 (July 15, 2020): 5673. http://dx.doi.org/10.3390/su12145673.

Full text

Abstract:

To meet the indoor heat load demand of greenhouses in China rural areas in winter, the authors proposed and designed a novel biomass heating system in greenhouses. The system uses biomass flue gas as the thermal working medium and heats the shallow soil inside the greenhouse through the buried flue gas-soil heat exchanger, thereby improving the indoor thermal environment of the greenhouse. To further study the heating system performance, we built up the heating experimental platform in a plastic greenhouse. Through testing the actual operation effect of the biomass heating system of the plastic greenhouse, no taking any heating measures system, the biomass heating system of the plastic greenhouse can improve the air average temperature and the soil average temperature 5.1 °C and 8.2 °C, respectively. The greenhouse biomass heating system is very economical, compared with the greenhouse without heating system, which can bring a 105% excess return rate for farmers every year. This study has obvious significance to promote the sustainable development of rural agriculture and the efficient utilization of rural biomass resources.

APA, Harvard, Vancouver, ISO, and other styles

15

Chilingar, G. V., O. G. Sorokhtin, L. Khilyuk, and M. V. Gorfunkel. "Greenhouse gases and greenhouse effect." Environmental Geology 58, no. 6 (November 14, 2008): 1207–13. http://dx.doi.org/10.1007/s00254-008-1615-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Gent*, Martin P. N. "Effect of Shade on Quality of Greenhouse Tomato." HortScience 39, no. 4 (July 2004): 759A—759. http://dx.doi.org/10.21273/hortsci.39.4.759a.

Full text

Abstract:

Shading a greenhouse increased the fraction of tomatoes that were marketable, and the marketable yield, in a comparison of greenhouse tomato yields across years, in some of which the greenhouses were shaded. In 2003, the yield and quality of greenhouse tomatoes were compared directly when grown in spring and summer in Connecticut in identical greenhouses that differed only in the degree of shade. Each half of four greenhouses was either unshaded or shaded using reflective aluminized shade cloth rated to reduced light transmission by 15%, 30%, or 50%. Each shade treatment was repeated in two houses. Tomatoes were germinated in February and transplanted in March The houses were shaded when fruit began to ripen in early June. Picking continued through August. The effect of shade on total yield developed gradually. Yields in June were unaffected by shade, but in August yield under no shade was about 30% higher than under 50% shade. In contrast, there was an immediate effect of shade on fruit size. Fruit picked in June from plants under 50% shade was 16% smaller than from plants grown under no shade. This difference declined later in the season, to 6 and 9%, in July and August respectively. The highest yield of marketable fruit in 2003 was picked from houses under no shade, but this was only 10% more than picked from the houses under 50% shade. Shade increased the fraction of marketable fruit, from 54% under no shade to 63% under 50% shade. Certain defects were decreased by shade. For instance the fraction of fruit with cracked skin was decreased from 33% to 25%. In general, effects on fruit quality varied linearly with the degree of applied shade.

APA, Harvard, Vancouver, ISO, and other styles

17

Mcculloch, A., and JohnM Last. "GREENHOUSE EFFECT." Lancet 333, no. 8648 (May 1989): 1208–9. http://dx.doi.org/10.1016/s0140-6736(89)92791-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Villagrán, Edwin Andrés, and Carlos Ricardo Bojacá. "Effects of surrounding objects on the thermal performance of passively ventilated greenhouses." Journal of Agricultural Engineering 50, no. 1 (April 23, 2019): 20–27. http://dx.doi.org/10.4081/jae.2019.856.

Full text

Abstract:

The growing expansion of protected horticulture in many regions is occurring around densely populated areas where land for agriculture is scarce, expensive or is used for other purposes. Inexpensive plastic passively ventilated greenhouses are the common choice for protected cultivation in these developing regions. The objective of this work was to analyse the effect of surrounding constructions and natural obstacles on the thermal performance of two naturally ventilated greenhouses. A saw tooth type greenhouse (TCG), typical for Colombian production, and an optimised greenhouse (OG) alternative with greater ventilation areas were analysed using computational fluid dynamics (CFD) with and without the surrounding objects of a real environment. The results showed that air exchange rate of a greenhouse with restricted ventilation areas are greatly reduced when neighbouring objects are high enough. This ventilation restriction is intensified under low wind speed conditions. The temperature gradients of the OG greenhouse were lower than those of the TCG scenarios due to the increased ventilation rates. The rooftop ventilation index for the OG greenhouse was increased by 65% with respect to the TCG greenhouse index, resulting in a direct effect on the ventilation rates. An improved air exchange with the outside can be reached by increasing the greenhouse ventilation areas, especially the roof vents, to overcome the airflow restrictions imposed by the surrounding environment. This simulation exercise was validated with field temperature data collected for a real OG prototype built in the Bogota plateau, with results showing a similar pattern for the internal temperature gradient as exhibited by the CFD model.

APA, Harvard, Vancouver, ISO, and other styles

19

Butrico, Gina M., and David H. Kaplan. "Greenhouse Agriculture in the Icelandic Food System." European Countryside 10, no. 4 (December 1, 2018): 711–24. http://dx.doi.org/10.2478/euco-2018-0039.

Full text

Abstract:

Abstract Greenhouses are a frequent feature on the Icelandic rural landscape and an integral part of Iceland’s food system. Iceland’s reserves of geothermal energy present an opportunity to extend an otherwise short growing season. This promotes sustainability, increases food security, and benefits consumers. This article examines the relative strengths of Iceland’s greenhouse sector - using a combination of statistics, observations, and interviews to understand the resource demands of greenhouse agriculture, how well greenhouses can allay some food insecurity and provide local foods. It ends with an examination of how the reduction of subsidies used to keep greenhouse agriculture going, has had an effect and forces the question of whether losing much of Iceland’s agricultural sector and locally sourced food is worth the social and political costs.

APA, Harvard, Vancouver, ISO, and other styles

20

Urlić, Branimir, Marko Runjić, Katja Žanić, Marija Mandušić, Gabriela Vuletin Selak, Igor Pasković, and Gvozden Dumičić. "Effect of partial root-zone drying on grafted tomato in commercial greenhouse." Horticultural Science 47, No. 1 (March 31, 2020): 36–44. http://dx.doi.org/10.17221/130/2018-hortsci.

Full text

Abstract:

For two years, the tomatoes (cv. ‘Belle’ and ‘Clarabella’), ungrafted, self-grafted and grafted onto the ‘He-man’ rootstock, were grown under two irrigation regimes, i.e., partial-root zone drying (PRD) and fully irrigated (FI), to investigate whether grafting can alleviate drought stress and promote water-use efficiency (WUE). The grafted plants under the FI regime had the highest vegetative growth, which was the result of more leaves and greater leaf area and were only significantly different from the PRD grown ungrafted plants. The grafted plants had the highest yield as a result of the greater number of larger fruits and the yield did not differ between the irrigation treatments. No differences were found in the leaf NPK concentrations, while the Ca and Mg were higher under the PRD regime. The ungrafted plants under the PRD regime had the highest total soluble solids and acidity in the fruit juice. The grafted plants had a significantly higher WUE, more pronounced in the PRD regime. The different types of irrigation did not influence the vegetative growth and the yield in the greenhouse grown grafted tomato. The PRD and rootstock effects should be additionally investigated with deficit irrigation.

APA, Harvard, Vancouver, ISO, and other styles

21

Sinanoglou, Vassilia J., Angeliki Kavga, Irini F. Strati, Georgios Sotiroudis, Dimitra Lantzouraki, and Panagiotis Zoumpoulakis. "Effects of Infrared Radiation on Eggplant (Solanum melongena L.) Greenhouse Cultivation and Fruits’ Phenolic Profile." Foods 8, no. 12 (December 2, 2019): 630. http://dx.doi.org/10.3390/foods8120630.

Full text

Abstract:

The implementation of Infrared (IR) radiation in heated greenhouses possesses the advantage of high directional control and focused compensation of energy losses, appropriate for creating local microclimate conditions in highly energy-consuming systems, such as greenhouses. Moreover, it can efficiently maintain favorable environmental conditions at the plant canopy. The present study studies the application of Infrared (IR) heating in an experimental greenhouse with eggplant (Solanum melongena L.) cultivation. The experimental results are presented from a full cultivation period inside two identical, small scale experimental greenhouses, with IR and forced air heating system, respectively. The effects of IR heating over plant growth parameters, including the yield of the fruits as well as the total phenolic content and the antioxidant profile of eggplants fruits’ extracts are measured and discussed. The results indicate a greater uniformity production in the IR heating greenhouse in terms of antioxidant and radical scavenging activities, as well as the total phenolic content. Moreover, the phenolic profile of eggplant fruits from both greenhouses revealed the existence of numerous bioactive compounds, some of which were only characteristic of the eggplant fruits from IR heated greenhouses.

APA, Harvard, Vancouver, ISO, and other styles

22

Mónaco, C. I., H. Alippi, I. Mittidieri, and A. I. Nico. "SAPROPHYTIC FUNGI ON TOMATO PHYLLOPLANE: EFFECT OF FUNGICIDES AND LEAF POSITION ON ABUNDANCE, COMPOSITION AND DIVERSITY." Acta Agronomica Hungarica 49, no. 3 (September 1, 2001): 243–50. http://dx.doi.org/10.1556/aagr.49.2001.3.5.

Full text

Abstract:

Fungal isolations were made from leaves of tomato plants cultivated in greenhouses in an area close to La Plata, Argentina. Three different schemes of fungicide application were evaluated: high frequency preventive sprayings (Commercial Greenhouse I), low frequency preventive applications (Commercial Greenhouse II) and no fungicide spraying (Control Greenhouse). Leaves were sampled immediately after second fruit formation from three levels of the foliage: low, medium and high. Plating dilution was used to isolate fungal species. Total c.f.u. number and species composition and diversity were assessed by the plating dilution technique. Fungal populations were most abundant on leaves from lower parts of the foliage in the Control Greenhouse. Diversity varied according to fungicide application frequency and leaf position in the canopy. Higher values were recorded for lower leaves in the Control Greenhouse compared with upper leaves from Commercial Greenhouse II. Likewise position in the canopy influenced the frequency of some species. The implications for natural biological control are discussed. Key words: biodiversity, biological control, phylloplane, tomato

APA, Harvard, Vancouver, ISO, and other styles

23

Nicodemo, Daniel, Euclides Braga Malheiros, David De Jong, and Regina Helena Nogueira Couto. "Improved Pollination Efficiency and Reduced Honey Bee Colony Decline in Greenhouses by Allowing Access to the Outside During Part of the Day." Sociobiology 65, no. 4 (October 11, 2018): 714. http://dx.doi.org/10.13102/sociobiology.v65i4.3455.

Full text

Abstract:

Although honey bees are efficient pollinators of many crops cultivated in greenhouses, it is difficult to maintain colony strength and consequently pollination efficiency. Many bees die under greenhouse conditions and the colonies rapidly weaken. We examined the effect of adaptations to the hive entrance that allowed control of whether and when bees had access to the outside environment to see how it would affect pollination efficiency and colony condition in greenhouses with flowering cucumber (Cucumis sativus) plants in comparison with colonies that remained constantly inside the greenhouse, previously left in a dark environment or not. We recorded the type and period of visitation to the cucumber flowers, numbers of honey bees entering and leaving the two entrance hives and the effect of this type of management on the quantity of brood and food. Fiveframe Langstroth “nucleus” colonies were equipped with two 30 square centimeter entrances and two 3.0 cm diameter circular openings. Allowing the bees to make visits outside the greenhouse in early morning with redirection of bees into the greenhouse at 8.30 a.m. did not reduce visitation to cucumber flowers in the greenhouse. Maintaining colonies in the greenhouse reduced brood area and food stores. These losses were significantly reduced in colonies that had access outside the greenhouse during the early morning. Another advantage of alternating access to the inside and the outside of the greenhouse was that there was less possibility of interactions between bees and people working on the crop, and also pesticides application could be made without directly affecting foraging bees.

APA, Harvard, Vancouver, ISO, and other styles

24

Tang, Yilian, Ming Li, and Xun Ma. "Study On Photovoltaic Modules On Greenhouse Roof For Energy And Strawberry Production." E3S Web of Conferences 118 (2019): 03049. http://dx.doi.org/10.1051/e3sconf/201911803049.

Full text

Abstract:

The aim of this study was to investigate the effect of PV modules mounted on top of a greenhouse, on the growth of strawberries and microclimate conditions as well as to estimate the generated energy. In this study, two greenhouses with the same volume were established. One greenhouse was equipped with the opaque photovoltaic (OPV) modules which accounted for 25.9% of the roof area, and the other was equipped with the semi-transparent photovoltaic (STPV) modules which accounted for 20% of the roof area. The maximum annual power generation of OPV and STPV modules was 880 and 388 kWh with 30° tilt angle, respectively, by simulating different tilt angles. The temperature under the OPV and STPV modules was 2.9 and 1.1 °C lower than the unshaded part in the greenhouses, respectively, at noon in clear weather, and had little effect on relative humidity. The photosynthetically active radiation (PAR) under OPV and STPV modules was reduced by 43.5% and 31.7%, respectively, under the PE film greenhouse. The contents of soluble solids in strawberries in OPV and STPV greenhouses were 16.4 and 15.7 mg/g respectively, which were higher than those in unshaded samples. The quality and yield of the strawberry samples under the shade of OPV were better than those of the STPV shade.

APA, Harvard, Vancouver, ISO, and other styles

25

KARADEMİR, Nadire. "A GEOGRAPHICAL OVERVIEW OF GREENHOUSE AGRICULTURE ACTIVITIES IN ERDEMLİ." Zeitschrift für die Welt der Türken / Journal of World of Turks 13, no. 1 (April 15, 2021): 375–99. http://dx.doi.org/10.46291/zfwt/130119.

Full text

Abstract:

Located in the Mediterranean region, Erdemli district has been on its way to becoming a greenhouse production center in recent years, with the effect of favorable climatic conditions. In the study, it was aimed to determine the current situation in Erdemli, where greenhouse cultivation is carried out intensively, the characteristics of the greenhouses, the problems encountered in production and to develop suggestions for their solution. For this purpose, a questionnaire application prepared by the researcher was carried out in order to reveal the current situation of greenhouse operators in the district. The data were analyzed using the SPSS program and tables were created. Maps showing the location, topography and land use status of the region were produced with the ArcMap 10.4 package program. Face-to-face meetings were held with greenhouse operators, brokers and traders. As a result, it has been observed that especially greenhouse agricultural activities in the region are carried out with traditional agricultural methods in smaller scale family businesses, mostly plastic greenhouses are used to produce tomatoes and cucumbers, and they are negatively affected by natural disasters and cost increases. Solutions for the detected problems are presented. Key Words: Greenhouse Agriculture, Vegetable-Fruit Production, Erdemli, Mersin.

APA, Harvard, Vancouver, ISO, and other styles

26

Atılgan, Atılgan, İbrahim Erdal, Hakan Aktaş, and Eren çetin. "Effects of The Use of Colored Cover Materials and Led Lighting in Greenhouses on Plant Nutrient Concentration: Case of Tomato Plant (Solanum lycopersicum L.)." Turkish Journal of Agriculture - Food Science and Technology 8, no. 12 (December 26, 2020): 2550–55. http://dx.doi.org/10.24925/turjaf.v8i12.2550-2555.3678.

Full text

Abstract:

In this study, the effects of four different color plastic greenhouse treatments on nutrient concentrations of leaf and fruit, leaf SPAD (Soil and Plant Analyzer Development) values and some yield parameters of tomato were tried to be determined. For this purpose, plastic greenhouses with Red (RedG), Blue (BlueG), Colorless (ConG) and white Led (LedG) lighting have been used as materials in the research. The used plastic greenhouses are 3 m in width, 6 m in length, 2 m in sidewall height and 2.8 m in roof ridge height. Led lighting is; Three hours of extra lighting is planned for one hour before sunrise, 2 hours after sunset. The research was carried out in ISUBU (Isparta), Faculty of Agriculture, field area in the summer season in 2019. The nutrient elements of K, Ca, Mg, P, Cu, Zn, Mn and Fe were determined in the leaf and of the tomato plant. It has been determined that four different greenhouse treatments have a positive effect on K, Ca, Cu, Zn, Fe nutrients in leaf, and K, Ca, P, Mg nutrient in fruit. In terms of SPAD values, all treatments were determined to be higher than the control treatment. It was determined that the highest SPAD value was in BlueG treatment. When the efficiency-related values are examined; It was determined that the highest fruit number, fruit weight and yield were in BlueG treatment. BlueG treatment was followed by RedG, ConG, and LedG treatment respectively in terms of efficiency. As a result, considering the effects of four different greenhouse treatments on macro and micronutrient nutritions SPAD values, and yield values, it was concluded that the most suitable treatments for tomato cultivation in greenhouses is BlueG treatment and RedG treatment should not be ignored.

APA, Harvard, Vancouver, ISO, and other styles

27

Roslan, N., M. E. Ya’acob, D. Jamaludin, Y. Hashimoto, M. H. Othman, A. Noor Iskandar, M. R. Ariffin, et al. "Dye-Sensitized Solar Cell (DSSC): Effects on Light Quality, Microclimate, and Growth of Orthosiphon stamineus in Tropical Climatic Condition." Agronomy 11, no. 4 (March 26, 2021): 631. http://dx.doi.org/10.3390/agronomy11040631.

Full text

Abstract:

The main challenge facing greenhouse designers is to achieve environment-appropriate greenhouses, especially in tropical regions. The excess radiant energy transmitted into the greenhouse predisposes plants to photo-inhibition and consequently reduces crop production. Lately, photovoltaic (PV) modules are equipped as a greenhouse rooftop to minimize the level of irradiation and air temperature in the greenhouse, simultaneously improving its energy consumption. Nevertheless, due to the low level of irradiation, denser conventional PV internal shading would influence the cultivated crops’ growth. Thus, Dye Sensitized Solar Cell (DSSC) possesses several attractive features such as transparent, sensitive to low light levels, and various color options that render DSSC a perfect choice able to serve substantially in energy buildings. This study assessed the microclimate conditions inside the greenhouse with semi-transparent DSSC mounted on top of it, describing the Photosynthetic Photon Flux Density (PPFD) (µmol m−2 s−1), Vapor Pressure Deficit VPD (kPa), relative humidity (%), and also temperature (°C). The Overall Thermal Transfer Value (OTTV), which indicates the average thermal energy transmission rate across the external layer of a structure envelope, is also presented. The effects of colored DSSC in altering the spectral of sunlight in reference to the Orthosiphon stamineus growth responses were determined. The information of the condition of DSSC greenhouse microclimate helps to identify the information for designing PV greenhouses and to produce income from both electric power and agronomic activity.

APA, Harvard, Vancouver, ISO, and other styles

28

Wang, Shichao, Zhujun Chen, Jun Man, and Jianbin Zhou. "Effect of Large Inputs of Manure and Fertilizer on Nitrogen Mineralization in the Newly Built Solar Greenhouse Soils." HortScience 54, no. 9 (September 2019): 1600–1604. http://dx.doi.org/10.21273/hortsci13542-18.

Full text

Abstract:

In China, greenhouse soils often receive large rates of different manures and have a high content of soil organic matter (SOM). Understanding changes in nitrogen (N) mineralization in soils of newly built greenhouses after their construction is important for managing N. Soil samples were obtained from solar greenhouses of different ages (0, 1, 2, and 3 years) located in the south edge of the Loess Plateau, China, at 0- to 20- and 20- to 40-cm depth. N mineralization in the soils was measured with the Stanford and Smith long-term aerobic incubation method over 30 weeks. SOM, total N, and the mineralized N in the 0- to 20-cm and 20- to 40-cm soil layers were significantly increased in the older greenhouses. The cumulative mineralized N in the 0- to 20-cm soil layer in different cultivation years was increased in each year since the greenhouses were established. For the greenhouses with the same age, the cumulative mineralized N in the 0- to 20-cm soil layer was greater than that in the 20- to 40-cm layer. The potentially mineralizable N (N0) both in the 0- to 20-cm and the 20- to 40-cm soil layers increased with the greenhouses’ age. Regression analysis indicated that when SOM increased 1 g·kg−1, N0 in the 0- to 20-cm and 20- to 40-cm depth increased 22.6 and 8.4 mg·kg−1, respectively. Therefore, as the N supply in soil increases with the age of the solar greenhouse, we suggest that the application rates of manure and synthetic fertilizer be reduced.

APA, Harvard, Vancouver, ISO, and other styles

29

Philipona, Rolf. "Atmospheric thermal radiation from historical measurements to investigations of the Earth's greenhouse effect." Meteorologische Zeitschrift 22, no. 6 (December 1, 2013): 771–75. http://dx.doi.org/10.1127/0941-2948/2013/0473.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Aberkani, Kamal, Xiuming Hao, Damien de Halleux, Martine Dorais, Stephen Vineberg, and André Gosselin. "Effects of Shading Using a Retractable Liquid Foam Technology on Greenhouse and Plant Microclimates." HortTechnology 20, no. 2 (April 2010): 283–91. http://dx.doi.org/10.21273/horttech.20.2.283.

Full text

Abstract:

Climate control is an important aspect of greenhouse crop management. Shading is one popular method for reducing excess solar heat radiation and high air temperatures in the greenhouse during the summer season. A new innovative technology has recently been developed and is based on the injection of liquid foam between the double layers of polyethylene of the greenhouse roof. The foam can be used as a shading method during the warm days of the summer. This is the first investigation into the effect of shading using the liquid foam technology on greenhouse and plant microclimates. Our research was conducted over 2 years in two different areas of Canada. Experimental greenhouses were retrofitted with the new technology. Tomato (Solanum lycopersicum) and sweet pepper (Capsicum annuum) were transplanted. Two shading strategies were used: 1) comparison of a conventional nonmovable shading curtain to the liquid foam shading system and application of liquid foam shading based only on outside global solar radiation; and 2) application of foam shading based on both outside global solar radiation and greenhouse air temperature. Data on the greenhouse microclimate (global solar radiation, air temperature, and relative humidity), the canopy microclimate (leaf and bottom fruit temperatures), and ventilation (opening/closing) were recorded. Our study showed that the retractable liquid foam technology improved greenhouse climate. Under some conditions (very sunny and hot days), a large difference in air temperature (up to 6 °C) was noted between the unshaded and shaded greenhouses as a result of liquid foam application (40% to 65% shading). Foam shading also increased relative humidity by 5% to 12%. Furthermore, bottom fruit temperatures stayed cooler 3 h after shading treatment was stopped. As well, a reduction in ventilation needs was observed with liquid foam shading.

APA, Harvard, Vancouver, ISO, and other styles

31

Abdel-Ghany, Ahmed, Ibrahim Al-Helal, Fahad Alkoaik, Abdullah Alsadon, Mohamed Shady, and Abdullah Ibrahim. "Predicting the Cooling Potential of Different Shading Methods for Greenhouses in Arid Regions." Energies 12, no. 24 (December 11, 2019): 4716. http://dx.doi.org/10.3390/en12244716.

Full text

Abstract:

Shading greenhouses in a hot and sunny climate is essential to reduce the inside greenhouse air temperature. However, the type and location of nets need to be addressed properly to determine the shading method that provides a better cooling effect on the greenhouse air. This study was conducted to evaluate the effects of five different shading methods on greenhouse microclimates, and to investigate the cooling potential of each method. Four greenhouse models covered with 200-µm thick plastic film were used for the study: one was kept as control (C), one was whitened with slaked lime (L), and two were shaded with white and black nets (50% shading factor) deployed simultaneously at two locations, in contact (WC, BC) and at 20-cm distance from the cladding film (WD, BD). The microclimatic parameters were measured inside and outside the greenhouse models, and the cooling potential (CP) was predicted for each shading method. The results showed that the black net at 20-cm distance (BD) is desirable as it provides high CP with a reasonable solar radiation transmission. The maximum CP was estimated as 8.5 °C, 8 °C, 6 °C, 3.2 °C, and 2.1 °C for L, BD, BC, WD, and WC, respectively. Shading with white nets is not recommended because their cooling potential is very low. Based on these results, we developed correlations for predicting the CP for each shading method as a function of the transmitted solar radiation flux (Si). These correlations depend on Si. Accordingly, they can be used for small greenhouses, whitewashed with a slaked lime of any concentration, or shaded with a black net having any shading factor.

APA, Harvard, Vancouver, ISO, and other styles

32

Aissa, Mohammed, and Azzedine Boutelhig. "CFD Comparative Study Between Different Forms of Solar Greenhouses and Orientation Effect." International Journal of Heat and Technology 39, no. 2 (April 30, 2021): 433–40. http://dx.doi.org/10.18280/ijht.390212.

Full text

Abstract:

Only scarce studies that were adopted have considered two properties, the structure safety and energy, where the aero-dynamic and energetic phenomena were taken into account simultaneously in the agricultural greenhouses area. In fact, in this numerical study, the response of the greenhouse has been investigated in outside climate conditions, by considering the orientation relatively to the wind direction velocity and solar trajectory. A resolution of the physical problem combined between the thermal and dynamical fluid flow equations have been based on the Ansys Fluent software. The results showed that the difference between inside and outside air temperature of greenhouse has been strongly affected by the reorientation of the tunnel greenhouse structure, or by the design of the tunnel structure that was adopted in the dome and chapel shape. Moreover, the safety properties of greenhouse structure linked to the drag stress can be developed when based on the interaction fluid-structure analysis. In this view, a temperature profile evolution versus different heights inside greenhouse was highlighted. As well as like continues of our previous study of the drag evolution over tunnel design body proved by the results found in the literature will be compared with chapel and dome designs.

APA, Harvard, Vancouver, ISO, and other styles

33

Liang, H., V. Lukyanov, S. Cohen, D. Shapiro, U. Adler, D. Silverman, and J. Tanny. "Microclimate in naturally ventilated tunnel greenhouses: effects of passive heating and greenhouse cover." Acta Horticulturae, no. 1170 (July 2017): 269–76. http://dx.doi.org/10.17660/actahortic.2017.1170.32.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Contreras, Juana I., Rafael Baeza, José G. López, Gema Cánovas, and Francisca Alonso. "Management of Fertigation in Horticultural Crops through Automation with Electrotensiometers: Effect on the Productivity of Water and Nutrients." Sensors 21, no. 1 (December 30, 2020): 190. http://dx.doi.org/10.3390/s21010190.

Full text

Abstract:

Water and nutrient requirements of horticultural crops are influenced by different factors such as: Type of crop, stage of development and production system. Although greenhouse horticultural crops are more efficient in the use of water and fertilizers compared to other production systems, it is necessary increase efficiency for which individualized fertigation strategies must be designed for each greenhouse. The automation of fertigation based on the level of soil moisture allows optimization of management. The objective of this work was to determine the influence of the activation command of fertigation with electrotensiometers and the characteristics of the greenhouse on the productivity of the crop and the efficiency of use of water and nutrients in a sweet pepper crop. The trial was developed in two greenhouses. Four treatments were studied, combination of who two-factor: Soil matric potential (SMP) (SMP−10: Automatic activation of irrigation to −10 kPa and SMP−20: Automatic activation of irrigation to −20 kPa) and greenhouse characteristics (G1 and G2). The nutritive solution applied was the same in all treatments. The yield and volume of water and nutrients applied were determined, calculating the productivity of the water (WP), as well as productivity the nutrients. The fertigation activation threshold of −10 kPa presented the best results, increasing the yield and conserving WP and nutrient productivity with respect to −20 kPa in both greenhouses. The automation of irrigation with electrotensiometers allowed the application of different volume of fertigation demanded by the crop in each greenhouse, equalizing the WP and nutrient productivity without producing drainage. The pepper crop in the greenhouse G1 presented greater vegetative development, higher yield and demanded a greater volume of fertigation than G2 regardless of the activation threshold. This was due to the fact that the soil matric potential after irrigation in greenhouse G1 was closer to zero, being able to conclude that not only the soil matric potential threshold of irrigation activation has an influence on crop, but also the potential registered after irrigation. Soil matric potentials closer to zero are more productive.

APA, Harvard, Vancouver, ISO, and other styles

35

Zhang, Y., J. L. Shipp, and T. J. Jewett. "215 Effect of Overhead Misting on Leaf Surface Microclimate of Greenhouse Cucumber." HortScience 34, no. 3 (June 1999): 479B—479. http://dx.doi.org/10.21273/hortsci.34.3.479b.

Full text

Abstract:

Overhead fogging or misting is an essential technique applied in modern greenhouses for cooling and humidifying. This technique can be used to promote yield and quality of greenhouse crops either by providing favorable environment for the plant growth or by increasing the efficiency of greenhouse pest and disease control. In this study, the effect of high-pressure overhead misting on greenhouse climate and leaf surface microclimate conditions for cucumber crops in a glass greenhouse was investigated. It was found that the temperature of the greenhouse air was lowered by 5-6 °C and relative humidity was increased by 20% to 30% during misting. The temperature of sunlit leaves was slightly reduced in the morning (2-3 °C), and leaf wetness duration was significantly extended by misting. Leaf wetness duration under misting was predominately influenced by light intensity at the leaf level and was modelled as a function of misting period and average radiation intensity. Results of this study can be used to improve the predictions of pest and disease breakout and the efficiency of their control measures. The empirical model developed in this study can be integrated with leaf surface microclimate models to correctly predict surface moisture conditions and evaporative cooling from water films at the leaf surface.

APA, Harvard, Vancouver, ISO, and other styles

36

Berger, A., and Ch Tricot. "The greenhouse effect." Surveys in Geophysics 13, no. 6 (November 1992): 523–49. http://dx.doi.org/10.1007/bf01904998.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Qualter, Anne, Claire Francis, Edward Boyes, and Martin Stanisstreet. "The greenhouse effect." Education 3-13 23, no. 2 (June 1995): 28–31. http://dx.doi.org/10.1080/03004279585200151.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Andrews, David. "The “Greenhouse Effect”." Science Activities: Classroom Projects and Curriculum Ideas 23, no. 1 (March 1986): 27–29. http://dx.doi.org/10.1080/00368121.1986.9958013.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Hileman, Bette. "The greenhouse effect." Environmental Science & Technology 29, no. 2 (February 1995): 90A—93A. http://dx.doi.org/10.1021/es00002a715.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

PERMAN, ROGER. "Greenhouse effect economics." Nature 347, no. 6288 (September 1990): 10. http://dx.doi.org/10.1038/347010a0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Blanchet, Jean-Pierre, and Eric Girard. "Arctic ‘greenhouse effect’." Nature 371, no. 6496 (September 1994): 383. http://dx.doi.org/10.1038/371383a0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

McClenahan, John L. "The Greenhouse Effect." Annals of Internal Medicine 138, no. 5 (March 4, 2003): 434. http://dx.doi.org/10.7326/0003-4819-138-5-200303040-00017.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Prince, D. A. "The Greenhouse Effect." Weather 47, no. 12 (December 1992): 494. http://dx.doi.org/10.1002/j.1477-8696.1992.tb07140.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Kelly, P. M., and J. H. W. Karas. "The Greenhouse Effect." Capital & Class 13, no. 2 (July 1989): 17–28. http://dx.doi.org/10.1177/030981688903800102.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Mason, B. J. "The greenhouse effect." Contemporary Physics 30, no. 6 (November 1989): 417–32. http://dx.doi.org/10.1080/00107518908221990.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Bowman, John. "The greenhouse effect." Land Use Policy 7, no. 2 (April 1990): 101–8. http://dx.doi.org/10.1016/0264-8377(90)90002-g.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Martzopoulou, Anastasia, Dimitris Vafiadis, and Vassilios P. Fragos. "Energy Gain in Passive Solar Greenhouses Due to CO2 Enrichment." Energies 13, no. 5 (March 7, 2020): 1242. http://dx.doi.org/10.3390/en13051242.

Full text

Abstract:

The production cost of greenhouse cultivation depends mainly upon significant amounts of energy consumption in order to keep the optimum environmental condition for plant growth. Τhe expenditure on energy, either for heating or cooling, ranges between 30% to 60% of the total production costs, and any attempt to save energy will result in a positive effect on the potentiality of production accordingly, affecting the greenhouse product prices. Research has shown that CO2 enrichment in greenhouses significantly increases the yield of most indoor cultivation of plants of the C3 category. For these plants, when the CO2 concentration increases by three times above that of the atmosphere (380 ppm), the optimum plant growth temperature shifts higher by 5 °C to 10 °C reaching up to 30 °C to 32 °C. Therefore, huge amounts of solar energy can be captured inside the greenhouses, as the ventilation can be decreased. Alongside this, the use of a simple passive solar system consisting of plastic sleeves filled with water is considered to be an improved way to increase the energy inside greenhouses. In this work, three experimental trials were conducted to examine the benefit of the solar energy captured inside a greenhouse during CO2 enrichment at high temperatures. Finally, a modeling approach based on the heat loss equation was developed in order to establish the energy saving inside the greenhouses under the circumstances mentioned.

APA, Harvard, Vancouver, ISO, and other styles

48

Castellano, Sergio. "Photovoltaic greenhouses: evaluation of shading effect and its influence on agricultural performances." Journal of Agricultural Engineering 45, no. 4 (December 21, 2014): 168. http://dx.doi.org/10.4081/jae.2014.433.

Full text

Abstract:

During the last years, European government remuneration polices promoted the realisation of photovoltaic systems integrated with the structures instead of on ground photovoltaic (PV) plants. In this context, in rural areas, greenhouses covered with PV modules have been developed. In order to interdict the building of greenhouses with an amount of opaque panels on covering not coherent with the plant production, local laws assigned a threshold value, usually between 25% and 50%, of the projection on the soil of the roof. These ranges seem not to be based on scientific evaluation about the agricultural performances required to the building but only on empirical assessments. Purpose of this paper is to contribute to better understand the effect of different configurations of PV panels on the covering of a monospan duo-pitched roof greenhouse in terms of shading effect and energy efficiency during different periods of the year. At this aim, daylighting and insolation analysis were performed by means of the software Autodesk<sup>®</sup> Ecotect<sup>®</sup> Analysis (Autodesk, Inc., San Rafael, CA, USA) on greenhouse model with different covering ratio of polycrystalline photovoltaic panels on the roof.

APA, Harvard, Vancouver, ISO, and other styles

49

Bustamante Valencia, Nelson, John Fabio Acuña Caita, and Diego Luis Valera Martínez. "Effect of the height of the greenhouse on the plant - climate relationship as a development parameter in mint (Mentha Spicata) crops in Colombia." Ingeniería e Investigación 36, no. 2 (August 24, 2016): 6. http://dx.doi.org/10.15446/ing.investig.v36n2.52775.

Full text

Abstract:

The aim of the study is to evaluate the effect of the height of the greenhouse on climatic conditions generated on a mint crop (Mentha spicata). The tests were conducted in the town of Carmen de Viboral, 40 minutes away from the city of Medellin (6º 05’ 09” N and 75º 20’ 19” W, 2150 m.a.s.l.). Three greenhouses with the same dimensions were used, changing only the gutter height in 2 m, 2,5 m and 3 m respectively. Temperature and relative humidity measurements were taken every 30 minutes for 3 years, time during which crop production was assessed. Statistical analyses were performed to determine climatic variations caused by the difference in height between the greenhouses, and to determine differences in production levels. The results indicate that, under the study conditions, the greenhouse height directly affects the weather conditions and the mint crop yields.

APA, Harvard, Vancouver, ISO, and other styles

50

Akrami, Mohammad, Akbar A. Javadi, Matthew J. Hassanein, Raziyeh Farmani, Mahdieh Dibaj, Gavin R. Tabor, and Abdelazim Negm. "Study of the Effects of Vent Configuration on Mono-Span Greenhouse Ventilation Using Computational Fluid Dynamics." Sustainability 12, no. 3 (January 29, 2020): 986. http://dx.doi.org/10.3390/su12030986.

Full text

Abstract:

The rise in the human population, its density and scarcity of resources require cost-effective solutions for sustainable energy and water resources. Smart and sustainable agriculture is one important factor for future green cities to tackle climate change as a cost-effective solution to save energy and water. However, greenhouses (GH) require consistent ventilation due to their internal temperatures, and this can be an energy-intensive operation. Therefore, it is necessary to analyse the potential factors involved. In this study, the effect of vent configuration of a mono-span greenhouse with roof and side vents at low wind speeds was investigated using computational fluid dynamics (CFD). The validated simulations were then performed on different models to analyse the effects of the vents’ locations on the ventilation requirements. The side vents were found to contribute most to the ventilation. The position of the side vent was found to affect the convection loop in the greenhouse and the air velocity at the plant level. The humidity was shown to be highest under the windward side vent. The roof vent was found to affect the temperature and air velocity in the roof of the greenhouse but had very little effect on the distributions at the plant level.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Greenhoure effect'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles