Impact of Photosynthetically Active Radiation on Temperature, Relative Humidity, Wind Speed and Direction in Lubigi Cyperus papyrus L. Wetland Surface

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.

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Simulated Transport, Postproduction Irradiance Influence Postproduction Performance of Potted Roses

HortScience ◽

10.21273/hortsci.26.11.1401 ◽

1991 ◽

Vol 26 (11) ◽

pp. 1401-1404 ◽

Cited By ~ 4

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.

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Microclimate under different shading screens in greenhouses cultivated with bromeliads

Revista Brasileira de Engenharia Agrícola e Ambiental ◽

10.1590/s1415-43662012000800007 ◽

2012 ◽

Vol 16 (8) ◽

pp. 858-863 ◽

Cited By ~ 9

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.

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The net effect of ultraviolet radiation on atmospheric dimethylsulphide over the Southern Indian Ocean

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2004.1486 ◽

2005 ◽

Vol 363 (1826) ◽

pp. 187-189 ◽

Cited By ~ 3

Author(s):

Dominic R. Kniveton ◽

Martin C. Todd ◽

Jean Sciare ◽

Nikos Mihalopoulos

Keyword(s):

Wind Speed ◽

Indian Ocean ◽

Ultraviolet Radiation ◽

Surface Temperature ◽

Sea Surface Temperature ◽

Photosynthetically Active Radiation ◽

Inverse Relationship ◽

Sea Surface ◽

Southern Indian Ocean ◽

Active Radiation

Dimethylsulphide (DMS) in the atmosphere may play an important role in the climate system. This study shows an inverse relationship between ultraviolet extremes and atmospheric DMS, independent of changes in wind speed, sea–surface temperature and photosynthetically active radiation, as measured at Amsterdam Island in the Southern Indian Ocean.

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

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.126.1.134 ◽

2001 ◽

Vol 126 (1) ◽

pp. 134-139 ◽

Cited By ~ 9

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.

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

The Forestry Chronicle ◽

10.5558/tfc73075-1 ◽

1997 ◽

Vol 73 (1) ◽

pp. 75-82 ◽

Cited By ~ 12

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

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Effect of Coloured Agro-Net Covers on Insect Pest Control and Yield of Tomato (Solanum lycopersicon Mill)

Journal of Agricultural Science ◽

10.5539/jas.v9n12p283 ◽

2017 ◽

Vol 9 (12) ◽

pp. 283

Author(s):

Langàt Jelagat Caroline ◽

Mwanarusi Saidi ◽

Arnold Opiyo

Keyword(s):

Soil Moisture ◽

Relative Humidity ◽

Photosynthetically Active Radiation ◽

Block Design ◽

Control Treatment ◽

Solanum Lycopersicon ◽

Tomato Production ◽

Tomato Plants ◽

Active Radiation ◽

Neutral Colour

Tomato (Solanum lycopersicon Mill) is one of the most important vegetable crops consumed throughout the world; and is rich in important vitamins, minerals and antioxidants. Production of the crop in open fields is however constrained by several biotic and abiotic stresses that lead to low tomato yields and quality. This study aimed at determining the effects of coloured agro-net covers on microclimate, pest infestation and yield of tomato cultivar ‘‘Rio Grande’’. The study consisted of two trials conducted using a randomized complete block design (RCBD) with five replications and six treatments. Tomato plants were grown under blue, yellow, grey, white or multi-coloured net covers with a no net cover as the control. Data were collected on microclimate (temperature, soil moisture, relative humidity and photosynthetically active radiation), pest counts and crop yield variables. Net covering modified the tomato crop microclimate with highest temperatures and soil moisture and, relative humidity levels recorded under white (21.03 oC), blue (30.03%) and multi-coloured net covers (76.26%), respectively compared to the no net control treatment (16.32 oC, 14.82% and 64.90%). Photosynthetically active radiation (PAR) was lowest under the blue agro-net cover (416.09 µmol m-2 s-1) and highest under control treatment (985.00 µmol m-2 s-1). Tomato plants grown under coloured-colour nets (yellow and blue) had lower population of silverleaf whitefly, thrips and aphids while mite population was lower under neutral-colour net covers (white, grey and multi-coloured). The neutral-colour net covers (24938.87, 19525.16 and 21541.93 kg/ha) resulted in higher yields compared to coloured-colour net covers (16804.62 and 14551.05 kg/ha). Results of the study indicate that use of agro-net covers especially the neutral-colour net cover can improve microclimate, protect tomato against insect pests and can be considered a viable strategy for tomato production by smallholder growers.

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Net photosynthesis and stomatal conductance of red spruce twigs before and after twig detachment

Canadian Journal of Forest Research ◽

10.1139/x93-093 ◽

1993 ◽

Vol 23 (4) ◽

pp. 716-721 ◽

Cited By ~ 17

Author(s):

Fan-Rui Meng ◽

Paul A. Arp

Keyword(s):

Stomatal Conductance ◽

Relative Humidity ◽

New Brunswick ◽

Photosynthetically Active Radiation ◽

Regression Models ◽

Net Photosynthesis ◽

Leaf Temperature ◽

Red Spruce ◽

Active Radiation ◽

Before And After

Rates of net photosynthesis and stomatal conductance of red spruce (Picearubens Sarg.) twigs were measured in field conditions before and after twig detachment on clear midsummer days in New Brunswick. Although these variables did not change significantly within about 6 min after twig detachment, they did drop continually after detachment. Regression models for the rates of net photosynthesis and stomatal conductance were developed that can be used to simulate this drop. Photosynthetically active radiation, leaf temperature, relative humidity, and CO2 concentration were the principal covariates in these models. The regressions improved by including simulated leaf moisture values in the analysis of data obtained after twig detachment.

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

European Journal of Agriculture and Food Sciences ◽

10.24018/ejfood.2021.3.6.414 ◽

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.

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