scholarly journals Computational Fluid Dynamics Modelling of the Microclimate within the Boundary Layer of Leaves Leading to Improved Pest Control Management and Low-Input Greenhouse

2021 ◽  
Vol 13 (15) ◽  
pp. 8310
Author(s):  
Hicham Fatnassi ◽  
Thierry Boulard ◽  
Christine Poncet ◽  
Nikolaos Katsoulas ◽  
Thomas Bartzanas ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Pest Control ◽  
Fluid Dynamic ◽  
Natural Habitat ◽  
Greenhouse Production ◽  
Greenhouse Crops ◽  
Leaf Surfaces ◽  
Measurement Tools ◽  
Use Efficiency ◽  
Control Management

This work aims at using the Computational Fluid Dynamic (CFD) approach to study the distributed microclimate in the leaf boundary layer of greenhouse crops. Understanding the interactions in this microclimate of this natural habitat of plant pests (i.e., boundary layer of leaves), is a prerequisite for their control through targeted climate management for sustainable greenhouse production. The temperature and humidity simulations, inside the greenhouse, were performed using CFD code which has been adapted to simulate the plant activity within each mesh in the crop canopy. The air temperature and air humidity profiles within the boundary layer of leaves were deduced from the local surrounding climate parameters, based on an analytical approach, encapsulated in a Used Defined Function (UDF), and dynamically linked to the CFD solver, a work that forms an innovative and original task. Thus, this model represents a new approach to investigate the microclimate in the boundary layer of leaves under greenhouses, which resolves the issue of the inaccessibility of this area by the conventionnel measurement tools. The findings clearly showed that (i) contrarily to what might be expected, the microclimate parameters within the boundary layer of leaves are different from the surrounding climate in the greenhouse. This is particularly visible during photoperiods when the plant’s transpiration activity is at its maximum and that (ii) the climatic parameters in the leaf boundary layer are more coupled with leaf surfaces than with those of greenhouse air. These results can help developing localized intervention strategies on the microclimate within boundary layer of plant leaves, leading to improved and sustainable pest control management. The developed climatic strategies will make it possible to optimize resources use efficiency.

Photosynthesis and Transpiration in Damaged and Undamaged Spruce Trees

1996 ◽  
Vol 51 (3-4) ◽  
pp. 200-210 ◽  
Author(s):  
Aloysius Wild ◽  
Peter Sabel ◽  
Lucia Wild-Peters ◽  
Ursula Schmieden
Keyword(s):  
Gas Exchange ◽  
Water Potential ◽  
Natural Habitat ◽  
Late Summer ◽  
Net Photosynthesis ◽  
Diurnal Course ◽  
Physiological Homeostasis ◽  
Use Efficiency ◽  
Needle Loss ◽  
Light Saturation Curves

Abstract The investigations presented here focus on the CO2/H2O gas exchange in damaged and undamaged spruce trees while using open-air measurements as well as measurements under defined conditions in the laboratory. The studies were performed at two different sites in the Hunsrück and the Westerwald mountains. In the laboratory the CO2/H2O gas exchange was measured on detached branches under controlled conditions in the course of two years. CO2 saturation curves were also generated. In addition CO2 compensation points were deter­ mined employing a closed system. In the natural habitat diurnal course measurements of photosynthesis and transpiration as well as light-saturation curves for photosynthesis were performed. In parallel with the photosynthesis and transpiration measurements, measurements of the water potential were taken at both locations. The photosynthetic capacity and transpiration rate show a typical annual course with pronounced maxima in spring and late summer and minima in summer and winter. The needles of the damaged trees exhibit higher transpiration rates and a distinct reduction in photosyn­ thesis than the needles of the undamaged trees during two seasons. The diurnal course measurements of net photosynthesis and transpiration show a maximum in photosynthesis and transpiration in the afternoon in May and September, but a characteristic midday depression in July. Photosynthesis was markedly lower and transpiration higher in the needles of the damaged trees. The damaged trees show a lower increase in the light and CO2 saturation curves and higher CO2 compensation points as compared to the undamaged trees. The water potential reaches much lower values during the course of the day in needles of the dam­ aged trees. The reduction of the photosynthetic rate on one hand and the increase in transpiration on the other hand result in an extreme lowering of the water use efficiency in photosynthesis. The damage to the thylakoid membranes and to the guard cells obviously results in a pro­ found disturbance of the physiological homeostasis of the needles and could thus lead to premature needle loss.

scholarly journals Applications of solar and wind renewable energy in agriculture: A review

2019 ◽  
Vol 102 (2) ◽  
pp. 127-140 ◽  
Author(s):  
Yuliana de Jesus Acosta-Silva ◽  
Irineo Torres-Pacheco ◽  
Yasuhiro Matsumoto ◽  
Manuel Toledano-Ayala ◽  
Genaro Martín Soto-Zarazúa ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Fossil Fuels ◽  
Energy Systems ◽  
Energy System ◽  
Climate Control ◽  
Greenhouse Production ◽  
Renewable Energy Systems ◽  
Greenhouse Crops ◽  
Renewable Energy System ◽  
The Impact

The growing demand for food and the unstable price of fossil fuels has led to the search for environmentally friendly sources of energy. Energy is one of the largest overhead costs in the production of greenhouse crops for favorable climate control. The use of wind–solar renewable energy system for the control of greenhouse environments reduces fuel consumption and so enhances the sustainability of greenhouse production. This review describes the impact of solar–wind renewable energy systems in agricultural greenhouses.

scholarly journals On the generation of the mean velocity profile for turbulent boundary layers with pressure gradient under equilibrium conditions

2012 ◽  
Vol 116 (1180) ◽  
pp. 569-598 ◽  
Author(s):  
A. Rona ◽  
M. Monti ◽  
C. Airiau
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Velocity Profile ◽  
Pressure Gradient ◽  
Fluid Dynamic ◽  
Predictive Ability ◽  
Adverse Pressure Gradient ◽  
Computational Domain ◽  
Mean Velocity ◽  
Number Range

AbstractThe generation of a fully turbulent boundary layer profile is investigated using analytical and numerical methods over the Reynolds number range 422 ≤ Reθ≤ 31,000. The numerical method uses a new mixing length blending function. The predictions are validated against reference wind tunnel measurements under zero streamwise pressure gradient. The methods are then tested for low and moderate adverse pressure gradients. Comparison against experiment and DNS data show a good predictive ability under zero pressure gradient and moderate adverse pressure gradient, with both methods providing a complete velocity profile through the viscous sub-layer down to the wall. These methods are useful computational fluid dynamic tools for generating an equilibrium thick turbulent boundary layer at the computational domain inflow.

scholarly journals Tomato Spotted Wilt Virus Infection of Commercial Aphelandra sp.

1987 ◽  
Vol 5 (3) ◽  
pp. 120-121
Author(s):  
Robert S. Halliwell ◽  
Larry W. Barnes
Keyword(s):  
Virus Infection ◽  
Tomato Spotted Wilt Virus ◽  
New Disease ◽  
Greenhouse Production ◽  
Greenhouse Crops ◽  
Tomato Spotted Wilt ◽  
Wilt Virus

Tomato spotted wilt virus (TSWV) is becoming more prevalent in Texas crops. TSWV diseases are endemic in peanuts, tomatoes, peppers, and are becoming more of a problem in greenhouse crops. TSW of Aphelandra sp., is described as a new disease problem in commercial greenhouse production.

scholarly journals Evaluation of Greenhouse Cucumber Production Sustainability in Terms of Energy Use Efficiency

2020 ◽  
Vol 24 ◽  
pp. 24
Author(s):  
Nawal Khamis Al-Mezeini ◽  
Abdulrahim M. Al-Ismaili ◽  
Said M. Tabook
Keyword(s):  
Total Energy ◽  
Energy Use ◽  
Energy Output ◽  
Energy Productivity ◽  
Greenhouse Production ◽  
Energy Use Efficiency ◽  
Energy Inputs ◽  
Energy Consuming ◽  
Greenhouse Cucumber ◽  
Use Efficiency

Sustainable agricultural production could be assessed through energy-use efficiency (EUE). Thus, this paper aims to evaluate the EUE for cucumber greenhouse production in Oman. Data were obtained by interviewing farmers (face-to-face). Result indicated that total energy inputs (e.g. electricity, water, fertilizers and agrochemicals) and total energy output (cucumber yield) were 1159726.0 MJ ha-1 and 89942.9 MJ ha-1, respectively. The highest energy consuming input in the greenhouse production was electricity, consuming 88% of total energy input. This indicates that electricity had again the highest impact in cucumber greenhouse production and 99% of electricity goes for cooling the greenhouse. When all energy inputs were classified into its forms; direct (D) and indirect (ID), and renewable (R) and non-renewable (NR), the highest portion of total energy forms in greenhouse cucumber production was for D and NR energy. The EUE and energy productivity (EP) were found to be 0.07 and 0.10 kg MJ-1, respectively. Energy use in greenhouse cucumber production was inefficient and solar energy need to be implemented to improve cucumber greenhouse sustainability production.

scholarly journals Pepper Photosynthesis, Stomatal Conductance, Transpiration, and Water Use Efficiency Differ with Variety, Indigenous Habitat, and Species of Origin

HortScience ◽  
2019 ◽  
Vol 54 (10) ◽  
pp. 1662-1666
Author(s):  
John Erwin ◽  
Tanveer Hussein ◽  
David J. Baumler
Keyword(s):  
Stomatal Conductance ◽  
Relative Humidity ◽  
Water Use Efficiency ◽  
Water Use ◽  
Leaf Temperature ◽  
Greenhouse Production ◽  
Hot Peppers ◽  
Use Efficiency ◽  
Dry Climates ◽  
Tropical Climates

The instantaneous photosynthetic rate (Pn), transpiration rate (E), and stomatal conductance (gS) were measured for 33 outdoor-grown Capsicum varieties (varying in species of origin and indigenous habitat) between 29 July and 22 Aug. 2017 using a portable gas exchange meter. Cuvette leaf temperature (Tleaf) and relative humidity (RH) were recorded at that same time. Pn differed from 3.6 to 3.7 for ‘Malawi Piquante’ and ‘Korean Long Green’ peppers to 16.3 μmol CO2/m2/s (fixed) for ‘Thai Hot’ peppers. The gS differed from 0.01 to 0.05 among 13 varieties to 0.28 mmol H2O/m2/s for ‘Thai Hot’ peppers. E differed from 0.43 to 0.59 among three varieties to 4.14 to 4.20 mmol H2O/m2/s for ‘CGN 22091’ and ‘Peruvian Purple’ peppers. Water use efficiency (WUE; Pn/E) varied from 2.92 to 3.43 among three varieties to 5.10 to 7.20 for 16 other varieties. C. annuum derived varieties had higher Pn (9.4 μmol CO2/m2/s fixed) than varieties derived from other species (4.5–8.6 μmol CO2/m2/s fixed). Varieties originating from dry climates had higher Pn (12.5 μmol CO2/m2/s fixed) than those originating from temperate or tropical climates (8.0–8.8 μmol CO2/m2/s fixed). Tleaf (27 to 33 °C) and RH (38% to 39% and 57% to 59%) differed among varieties. Pn was positively correlated with gS, E, and RH and was negatively correlated with WUE. We found that Capsicum Pn, E, and gS varied more than has been previously reported, and our data suggested that Pn, gS, and E data of outdoor-grown peppers should be used only when selecting parents for a breeding program (unless progeny is intended for greenhouse production).

scholarly journals A step forward towards advanced and self-sustainable greenhouse agriculture

2020 ◽  
Author(s):  
Mohammad Nur E Alam ◽  
Mikhail Vasiliev ◽  
Jacqualine Thomas
Keyword(s):  
Biomass Productivity ◽  
Future Generation ◽  
Dielectric Thin Film ◽  
Greenhouse Crops ◽  
Land Use Efficiency ◽  
Spectrally Selective ◽  
Practical Development ◽  
Use Efficiency ◽  
Thin Film Filters

It is now time for the future-generation and advanced greenhouse design practices to address a range of issues, from the energy and land use efficiency to providing plant-optimised growth techniques. In this Encyclopaedia record, we report on the practical development of spectrally selective and specialist-type  advanced metal-dielectric thin-film filters that produce the optimized illumination spectrum when exposed to natural sunlight that can help maximize the biomass productivity of coated-glass greenhouse crops. Our experimental case study has been performed for the lettuce species, Lactuca sativa, L., yielding promising results.

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