scholarly journals Development of Suitable Microclimate Using Low˗tech Greenhouse for Off-Season Production of High Value Crops in Bangladesh

2021 ◽  
Vol 3 (6) ◽  
pp. 95-103
Author(s):  
M. A. Awal ◽  
P. C. Dhar ◽  
M. H. R. Pramanik
Keyword(s):  
Relative Humidity ◽  
Film Thickness ◽  
Air Temperature ◽  
Photosynthetically Active Radiation ◽  
Crop Production ◽  
Active Radiation ◽  
Horticultural Crops ◽  
Season Extension ◽  
Soil Temperatures ◽  
Solar Noon

Low˗tech greenhouses (low˗techs) have been used globally to cultivate horticultural crops since many years, but their utilization in Bangladesh is a recent phenomenon. Moreover, information on altered microclimate inside the low˗tech is hardly reported. An investigation has been conducted in the Crop Botany Field Laboratory, Bangladesh Agricultural University (24o72´N, 90o43´E and 18 masl), Mymensingh during the late autumn to winter seasons from mid-October to mid-February of 2015/16, 2016/17 and 2017/18 years to find out the variation in microclimatic parameters between inside and outside of low˗techs and to evaluate the suitability of altered microclimate inside the low˗techs for off˗season production of high value crops in Bangladesh. Three low˗techs were erected in each year using bamboo frame covered with single inflated polyethylene film (thickness = 0.2 mm). Major microclimatic parameters inside and aside outside the low˗techs were measured with standard devices or techniques. Around 30 percent incoming photosynthetically active radiation (PAR) was cut˗off by low˗tech cover during solar noon when the sun’s zenith gets minimum value (around 0o). However, this cut˗off portion of PAR was gradually increased with the sunrise and sunset when zenith is around 90o. During the daytime, low˗tech retains higher air temperature than that found at outside and the differences in air temperature between inside and outside of low˗techs was gradually increased after sunrise with a peak difference of 7 to 9 oC following the solar noon (i.e., 13:00-14:00 hour). No distinct variation in relative humidity was recorded between inside and outside of the low˗tech. Low˗tech cover retains higher soil temperature than that was recorded in outside. The variation of both air and soil temperatures between inside and outside of low˗techs was higher during the daytime but lower at nighttime or even at daytime when the sky remained overcast. The variation in microclimatic parameters under low˗techs not only protect the growing crops from climate vagaries during autumn, winter and spring seasons but also provide suitable warmer environment for growing many high value crops during that seasons and thus crop production in off˗season and/or season extension benefits can easily be achieved by low˗techs.

scholarly journals Microclimate under different shading screens in greenhouses cultivated with bromeliads

2012 ◽  
Vol 16 (8) ◽  
pp. 858-863 ◽  
Author(s):  
Ester Holcman ◽  
Paulo C. Sentelhas
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Air Temperature ◽  
Photosynthetically Active Radiation ◽  
External Condition ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Net Radiation ◽  
Active Radiation ◽  
Incoming Solar Radiation

This study had as its objective the evaluation of the influence of shading screens of different colors on the different microclimate variables in a greenhouse covered with transparent low-density polyethylene (LDPE). The experiment was conducted with five treatments: thermo-reflective screen (T1); a control - without screen (T2); red screen (T3); blue screen (T4); and black screen (T5), all of them with 70% of shading. An automatic micrometeorological station was installed in each treatment, measuring air temperature (T), relative humidity (RH), incoming solar radiation (Rg), photosynthetically active radiation (PAR) and net radiation (Rn) continuously. The control (T2) and red screen (T3) treatments promoted the highest solar radiation transmissivity, respectively 56.3 and 27%. The black screen (T5) had the lowest solar radiation transmissivity (10.4%). For PAR and Rn the same tendency was observed. The highest temperature was observed under blue screen (T4) treatment, which was 1.3 °C higher than external condition. Blue screen (T4) treatment also presented the highest relative humidity difference between inside and outside conditions.

scholarly journals Alternative conifer release treatments affect below- and near-ground microclimate

1997 ◽  
Vol 73 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Phillip E. Reynolds ◽  
Donald A. Buckley ◽  
James A. Simpson ◽  
Andrew M. Gordon ◽  
Donald A. Gresch ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Relative Humidity ◽  
Photosynthetically Active Radiation ◽  
Forest Floor ◽  
Growing Season ◽  
Active Radiation ◽  
Soil Temperatures ◽  
Glyphosate Herbicide ◽  
And Control ◽  
Thermistor Resistance

Li-Cor weather stations and thermistor/resistance soil cells were used during 1994 to monitor microclimate in young spruce plantations during the first growing season after the following replicated alternative conifer release treatments [brush saw, Silvana Selective, Release® (a.i., triclopyr) herbicide. Vision® (a.i., glyphosate) herbicide], and control (no treatment) were applied. Treatments were conducted in mid-August (herbicides) and late October and early November (cutting) 1993. In 1994, temperature, photosynthetically-active radiation (PAR), and relative humidity (RH) were monitored near (0.25 m) and above (2 m) the forest floor. Fiberglass thermistor/resistance soils cells were installed 15 and 30 cm deep, and soil moisture and temperature were read bimonthly. In relation to controls, PAR near and above the forest floor increased on all conifer release treatments. By July, PAR near the forest floor declined on both the cut and herbicide treatments. That decline occurred in early July for the brush saw treatment, but in late July for the Vision® treatment. PAR at 2 m was similar among conifer release alternatives and significantly greater than for controls throughout the growing season. Increased solar radiation resulted in significant soil warming following the conifer release treatments. During the growing season, duff (5 cm) and mineral (15 cm) soil temperatures were highest for the Vision® and Release® treatments, and lower on the brush saw and control treatments. November soil temperatures were slightly cooler in released than control plots. Frequent rains resulted in relatively high RH and soil moisture readings during the 1994 growing season. Relative humidity near the forest floor was lowest for the Vision®, intermediate for the brush saw, and highest for the control treatments. During the growing season after treatments, soil moisture levels were higher on treated than control plots. Key words: microclimate, alternative conifer release treatments, Fallingsnow Ecosystem Project, photosynthetically-active radiation (PAR), soil temperature and moisture, relative humidity, ecosystem study

scholarly journals Effect of shelterbelt on the microclimate of the gram (Cicer arietinum) crop

MAUSAM ◽  
2021 ◽  
Vol 47 (2) ◽  
pp. 173-178
Author(s):  
RAJ SINGH ◽  
O. P. BISHNOI ◽  
V. U. M. RAO ◽  
DIWAN SINGH
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Cicer Arietinum ◽  
Air Temperature ◽  
Photosynthetically Active Radiation ◽  
Minimum Temperature ◽  
Radiation Absorption ◽  
Active Radiation ◽  
Maximum Reduction

The shelterbelt influence on the microclimate of gram crop in different intercropping systems comprising of four treatment, viz., pure gram, 1 : 1, 2 : 1 and 4 : 1 gram and raya, was quantified. Albedo varied from 14.8 to 22.6 percent in various treatments with highest value fo 18.3 percent in pure gram treatment, whereas, photosynthetically active radiation absorption was highest in  2 : 1 gram treatment (76%). Maximum reduction (69.2 per cent) in wind speed was observed in  1 : 1 intercropping system at 4h distance from the edge of the shelterbelt in comparison to pure gram field. Relative humidity was 8 to 15 percent less in the sheltered gram as compare to the pure gram, whereas, the average air temperature increased by 1 to 2 C in the sheltered crop over that of the pure gram and this increase was in the range of  9.9 to 12.2 per cent at 4h distance from the edge of shelterbelt. The grass minimum temperature was higher by 0.7degree cent grate in 2 : 1 treatment over that of pure gram during the months of January and February.  

Influence of canopy microclimate on incidence and severity of dogwood anthracnose

1992 ◽  
Vol 70 (5) ◽  
pp. 1093-1096 ◽  
Author(s):  
Dan O. Chellemi ◽  
Kerry O. Britton
Keyword(s):  
Vapor Pressure ◽  
Air Temperature ◽  
Photosynthetically Active Radiation ◽  
Vapor Pressure Deficit ◽  
Disease Incidence ◽  
Cornus Florida ◽  
Active Radiation ◽  
Dogwood Anthracnose ◽  
Low Levels ◽  
Understory Trees

Incidence and severity of dogwood anthracnose within the interior and exterior canopies of exposed dogwood (Cornus florida L.) trees and canopies of understory trees were recorded over a 53-day period during the summer of 1990. Concurrent measurements of vapor pressure deficit, air temperature, evaporative potential, and photosynthetically active radiation within the canopies were also recorded. Disease incidence was significantly lower in the exterior canopy of exposed trees than in other canopy locations. Disease severity was significantly different among all three canopy locations, with the lowest severity in exterior canopies of exposed trees and the greatest severity in canopies of understory trees. Of the climatic variables measured, evaporative potential provided the most consistent contrast among microclimates at the various canopy locations. Mean evaporative potentials averaged over 6- to 10-day intervals ranged from 0.00 g H2O h−1 in understory and exposed, interior canopies to 0.40 g H2O h−1 in exposed, exterior canopies. Disease incidence and severity were greater in canopies associated with low levels of evaporative potential. Key words: Cornus florida L., dogwood anthracnose, canopy microclimate, evaporative potential.

scholarly journals Simulated Transport, Postproduction Irradiance Influence Postproduction Performance of Potted Roses

HortScience ◽  
1991 ◽  
Vol 26 (11) ◽  
pp. 1401-1404 ◽  
Author(s):  
Terril A. Nell ◽  
Cor Vonk Noordegraaf
Keyword(s):  
Relative Humidity ◽  
Photosynthetically Active Radiation ◽  
Active Radiation ◽  
Irradiance Level ◽  
Fluorescent Lamps ◽  
Level 1

Three simulated transport temperatures (5, 11, or 17C) and durations. (3, 6, or 9 days) were used to evaluate the postproduction flowering patterns of miniature potted rose (Rosa sp) `Orange Rosamini'. The postproduction environment was maintained at 20 ± lC, 60% ± 5% relative humidity (RI-I), and an irradiance level, from cool-white fluorescent lamps, of 4.5 W·m-2 photosynthetically active radiation (PAR) for 12 hours daily to simulate conditions at the retail or consumer level. At 3 weeks postproduction, plants held for 9 days at 17C had the fewest buds showing color per plant. As temperature increased, there were fewer flowers per plant at weeks 2 and 3 of postproduction. In a second study, the effect of simulated transport (3 days at 5C vs. no transport) and postproduction irradiance level (1, 2, or 4 W·m-2 PAR) were evaluated over a 7-week postproduction period for `Orange Rosamini'. A three-way interaction was observed between simulated transport treatment, postproduction irradiance level, and time in postproduction for the number of open flowers per plant. Plants responded similarly at 1 and 2 W·m2 throughout the postproduction period, regardless of transport treatment; however, at 4 W·m-2 the plants of the no transport treatment had two to three open flowers each week up to week 6 of postproduction, while plants subjected to simulated transport followed the pattern of one and two open flowers for 0 to 3 weeks. Flowering then increased to three to four open flowers for the duration of the postproduction period. A third study involved two simulated transport treatments (3 days at SC vs. no transport), three postproduction irradiance levels (1, 2, and 4 W·m-2 PAR), and six miniature rose cultivars (`Orange Rosamini', `Red Minimo' `Sweet Rosamini', `Golden Rosamini', `Favorite Rosamini', and `White Rosamini'). Plants held at 1 or 2 W·m-2 for 3 weeks had no open flowers, while those held at 4 W·m-2 for 3 weeks had one to four open flowers, except `Sweet Rosamini', which had no open flowers with simulated transport.

scholarly journals Effects of External Coloured Shade Nets on Sweet Peppers Cultivated in Walk-in Plastic Tunnels

2015 ◽  
Vol 43 (2) ◽  
pp. 398-403 ◽  
Author(s):  
Attila OMBÓDI ◽  
Zoltán PÉK ◽  
Péter SZUVANDZSIEV ◽  
Zsuzsanna TÓTHNÉ TASKOVICS ◽  
Ambrus KOHÁZI-KIS ◽  
...  
Keyword(s):  
Chlorophyll Content ◽  
Air Temperature ◽  
Photosynthetically Active Radiation ◽  
Incident Radiation ◽  
Climatic Conditions ◽  
Active Radiation ◽  
Negative Relation ◽  
Spad Value ◽  
Positive Linear Relation ◽  
Relative Chlorophyll Content

Shading effect of external nets of different colours (white, green, yellow and red) on the yield of two “kapija” pepper (Capsicum anuum L.) cultivars was examined in walk-in plastic tunnels in Hungary under real cultivation circumstances. Shading nets decreased incoming radiation by 23-39% and reduced photosynthetically active radiation by 32-46%. The highest retention was obtained by yellow and green nets, in the range of 450-550 nm and 550-670 nm, respectively. Relation was reported between the degree of shading and the average air temperature of the tunnels, however, treatments did not decrease tunnel air temperature significantly, compared to that of unshaded and paint-shaded control tunnels. This can be explained by the applied proper ventilation and mist irrigation. A strong and negative relation was noted between the intensity of shading and the relative chlorophyll content (SPAD value) of leaves. Shading net treatments did not increase yields, yellow and green nets even decreased it. Instead of tunnel air temperature, yield was mainly affected by photosynthetically active radiation in the experiment. Strong positive linear relation was declared between the chlorophyll content of the leaves and the yield. Results of the current research led to the conclusions that under Hungarian climatic conditions the use of shading nets was less justified if proper cooling techniques (ventilation and mist irrigation) were applied; even under the relatively high incident radiation experienced during the trials. In greenhouses of less favourable climatic conditions, red or white shading nets are recommended instead of commonly used green ones in Hungary.

Photobiological Control of Crop Production and Plant Diseases

2008 ◽  
Vol 63 (1-2) ◽  
pp. 113-123
Author(s):  
Kiriakos Kotzabasis ◽  
Eleni Navakoudis ◽  
Demetrios J. Vakalounakis
Keyword(s):  
Photosynthetically Active Radiation ◽  
Comparative Studies ◽  
Fungal Pathogen ◽  
Crop Production ◽  
Photosynthetic Activity ◽  
Plant Productivity ◽  
Plant Diseases ◽  
Spectral Ratios ◽  
Tomato Plants ◽  
Active Radiation

Plants, as well as fungi, use ambient sunlight as information to regulate photomorphogenetic processes. The photobiological control of this information showed that the development of photobiological greenhouse plastic covers simulates a photonic information that leads to a physiological enhancement of plant productivity and fungal disease control, thus minimizing the need for the use of agrochemicals. The main characteristics of these photobiological greenhouse plastic covers are the high transmission of photosynthetically active radiation (PAR, 400 − 700 nm) combined with an increase of the factor ζ =RL(655 −665 nm)/FRL(725 −735 nm), which affects the cellular phytochromic equilibrium Φ = Pfr/(Pfr + Pr) and regulates the photosynthetic activity and therefore the plant productivity. Additionally, increase of the spectral ratios from the transmitted light: BL(420-500 nm)/nearUV(290-370 nm) and BL(420 −500 nm)/ FRL(725 −735 nm), cause mainly the induction of biochemical, physiological and morphological responses, regulated by cryptochromes in plants (e. g. inflorescence and infructescence) and mycochrome in fungi (e. g. inhibition of sporulation). In the present work, comparative studies with randomly selected greenhouse plastics showed that small changes in the abovementioned “photobiological” parameters raise the productivity of tomato plants and inhibit the sporulation of several isolates of the fungal pathogen Botrytis cinerea. Thus, a model for the photoregulation of these two phenomena in greenhouses is proposed.

scholarly journals Postproduction of Potted Miniature Rose: Flower Respiration and Single Flower Longevity

2001 ◽  
Vol 126 (1) ◽  
pp. 134-139 ◽  
Author(s):  
José A. Monteiro ◽  
Terril A. Nell ◽  
James E. Barrett
Keyword(s):  
Relative Humidity ◽  
Metabolic Rate ◽  
Respiration Rate ◽  
Photosynthetically Active Radiation ◽  
Flower Longevity ◽  
Active Radiation ◽  
Respiration Rates ◽  
Single Flower ◽  
The Relationship ◽  
Days After Anthesis

Research was conducted to investigate the relationship between flower respiration and flower longevity as well as to assess the possibility of using miniature rose (Rosa hybrida L.) flower respiration as an indicator of potential flower longevity. Using several miniature rose cultivars as a source of variation, four experiments were conducted throughout the year to study flower respiration and flower longevity under interior conditions. For plants under greenhouse as well as interior conditions, flower respiration was assessed on one flower per plant, from end-of-production (sepals beginning to separate) up to 8 days after anthesis. Interior conditions were 21 ± 1 °C and 50 ± 5% relative humidity with a 12-hour photoperiod of 12 μmol·m-2·s-1 (photosynthetically active radiation). Flower respiration was higher if the plants were produced during spring/summer as compared to fall/winter. `Meidanclar', `Schobitet', and `Meilarco' miniature roses had higher flower respiration rates than `Meijikatar' and `Meirutral'. These two cultivars with the lowest respiration rates showed much greater flower longevity if grown during spring/summer as compared to fall/winter. The three cultivars with the higher respiration rates did not show differences in flower longevity between seasons. For plants under greenhouse or interior conditions, flower respiration was negatively correlated with longevity in spring/summer but a positive correlation between these parameters was found in fall/winter. During spring/summer, flower respiration rate appears to be a good indicator of potential metabolic rate, and flowers with low respiration rates last longer.

scholarly journals Microclimate and radiant energy measurements using a novel device for natural resource monitoring

2016 ◽  
Author(s):  
Taylor Thomas ◽  
Adam Wolf
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Radiant Energy ◽  
Barometric Pressure ◽  
Net Radiation ◽  
Resource Monitoring ◽  
Energy Monitoring ◽  
Active Radiation ◽  
Novel Device ◽  
Natural Resource Monitoring

ABSTRACTA novel device for microclimate and radiant energy monitoring of natural resources was compared to known reference instruments and sensors to gauge relative performance under field conditions in Nebraska and New Jersey, USA during summer 2016. For all measurements tested, including air temperature, relative humidity, barometric pressure, four component net radiation, and photosynthetically active radiation, the device reported values near or within the accuracy limits as stated by the reference instrument / sensor manufacturer.

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