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 Bromeliads production in greenhouses associated to different shading screens

2013 ◽  
Vol 31 (3) ◽  
pp. 386-391 ◽  
Author(s):  
Ester Holcman ◽  
Paulo Cesar Sentelhas
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Growth And Development ◽  
Statistical Design ◽  
Leaf Length ◽  
Low Density Polyethylene ◽  
Leaf Width ◽  
Low Density ◽  
Aechmea Fasciata ◽  
Number Of Leaves

Bromeliads production in greenhouses is highly influenced by microclimate, which affects plants growth and development. Based on that, this study aimed to evaluate the influence of shading screens of different colors on microclimatic variables and Aechmea fasciata bromeliad growth in a greenhouse covered by transparent low-density polyethylene. The experiment had five treatments, with screens of different colors, inside a plastic greenhouse: thermo-reflective (T1); control without screen (T2); red (T3); blue (T4); and black (T5) screens, all of them with 70% of shading. From the 60 plants arranged in each one of the treatments 24 were evaluated, which were obtained randomly. The statistical design was completely randomized for the biometric variables. An automatic micrometeorological station was installed in each treatment, recording temperature, relative humidity and solar radiation. The plant parameters evaluated weekly were plant diameter and height, leaf width and length, and number of leaves per plant. The rosette diameter and leaf length were the parameters that presented the highest differences among treatments, which was basically a function of changes in solar radiation caused by the shading screens. The red screen provided the best conditions for A. fasciata bromeliad production.

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.

scholarly journals Modeling Regional Vegetation NPP Variations and Their Relationships with Climatic Parameters in Wuhan, China

2013 ◽  
Vol 17 (4) ◽  
pp. 1-20 ◽  
Author(s):  
Lunche Wang ◽  
Wei Gong ◽  
Yingying Ma ◽  
Miao Zhang
Keyword(s):  
Air Temperature ◽  
Photosynthetically Active Radiation ◽  
Vegetation Index ◽  
Climatic Factors ◽  
Global Radiation ◽  
Air Pressure ◽  
Stress Factors ◽  
Net Radiation ◽  
Active Radiation ◽  
Sunshine Hours

Abstract Net primary productivity (NPP) is an important component of the carbon cycle and a key indicator of ecosystem performance. The aim of this study is to construct a more accurate regional vegetation NPP estimation model and explore the relationship between NPP and climatic factors (air temperature, rainfall, sunshine hours, relative humidity, air pressure, global radiation, and surface net radiation). As a key variable in NPP modeling, photosynthetically active radiation (PAR) was obtained by finding a linear relationship between PAR and horizontal direct radiation, scattered radiation, and net radiation with high accuracy. The fraction of absorbed photosynthetically active radiation (FPAR) was estimated by enhanced vegetation index (EVI) instead of the widely used normalized difference vegetation index (NDVI). Stress factors of temperature/humidity for different types of vegetation were also considered in the simulation of light use efficiencies (LUE). The authors used EVI datasets of Moderate Resolution Imaging Spectroradiometer (MODIS) from 2001 to 2011 and geographic information techniques to reveal NPP variations in Wuhan. Time lagged serial correlation analysis was employed to study the delayed and continuous effects of climatic factors on NPP. The results showed that the authors’ improved model can simulate vegetation NPP in Wuhan effectively, and it may be adopted or used in other regions of the world that need to be further tested. The results indicated that air temperature and air pressure contributed significantly to the interannual changes of plant NPP while rainfall and global radiation were major climatic factors influencing seasonal NPP variations. A significant positive 32-day lagged correlation was observed between seasonal variation of NPP and rainfall (P < 0.01); the influence of changing climate on NPP lasted for 64 days. The impact of air pressure, global radiation, and net radiation on NPP persisted for 48 days, while the effects of sunshine hours and air temperature on NPP only lasted for 16 and 32 days, respectively.

scholarly journals Balanço de Radiação em Ecossistema de Caatinga Preservada Durante um Ano de Seca no Semiárido Pernambucano (Radiation Balance in Caatinga Ecosystem Preserved for a Year Drought in Semiarid Pernambucano)

2015 ◽  
Vol 8 (1) ◽  
pp. 041
Author(s):  
Luciana Sandra Bastos de Souza ◽  
Magna Soelma Beserra de Moura ◽  
Gilberto Chohaku Sediyama ◽  
Thieres George Freire da Silva
Keyword(s):  
Seasonal Variation ◽  
Solar Radiation ◽  
Photosynthetically Active Radiation ◽  
Climatic Conditions ◽  
Semiarid Region ◽  
Radiation Balance ◽  
Net Radiation ◽  
Active Radiation ◽  
Brazilian Semiarid ◽  
Semi Arid

O objetivo deste trabalho foi analisar as variações diárias e sazonais dos componentes do balanço de radiação e da radiação fotossinteticamente ativa para a caatinga preservada durante um ano seco no Semiárido pernambucano. O experimento foi conduzido durante o ano de 2012 em Petrolina, PE, localizado na região do Semiárido brasileiro. Para determinação dos componentes do balanço de radiação foi utilizado um saldo radiômetro modelo CNR1 instalado à 13,3 metros da superfície. Adicionalmente, analisou-se a interação entre a vegetação e a radiação por meio de sensores para o monitoramento da radiação fotossinteticamente ativa acima e em diferentes posições abaixo do dossel da caatinga. Estes dados foram utilizados no cálculo da fração da radiação fotossinteticamente ativa interceptada (fRFAi) e absorvida (fRFAa). Foi observada uma ampla variação sazonal da radiação solar global e do saldo de radiação que atingiram valores médios diários em torno de 23 MJ m-2 dia-1 e 15 MJ m-2 dia-1, respectivamente. Neste caso, observou-se que a magnitude dos valores dos componentes do balanço de radiação foi afetada principalmente em decorrência da nebulosidade e mudanças na vegetação que afetaram principalmente os níveis de emitância da superfície e sua reflexão. No que se refere às frações da radiação fotossinteticamente ativa interceptada e absorvida, observou-se que as mesmas apresentaram valores médios diários ao longo do ano bastante próximos, os quais foram iguais a 0,69 e 0,64, nesta ordem. Estes dados podem ser extremamente úteis para uma melhor compreensão da interação entre a caatinga e a atmosfera sob condições climáticas singulares, e portanto, serem utilizados na formulação de políticas climáticas.   A B S T R A C T The objective of this study was to analyze the daily and seasonal variations of the components of the radiation balance and photosynthetically active radiation for the Caatinga during a dry year in Pernambuco Semi-Arid. The experiment was conducted during the year 2012 in Petrolina, PE, located in the Brazilian semiarid region. To determine the components of the radiation balance we used a balance radiometer CNR1 model installed the 13.3 meters of surface. Additionally, we analyzed the interaction between vegetation and radiation using sensors to monitor the photosynthetically active radiation above and in different positions under the canopy of scrub. These data were used to calculate the fraction of intercepted photosynthetically active radiation (fRFAi) and absorbed (fRFAa). A wide seasonal variation of solar radiation and net radiation was observed that reached daily averages around 23 MJ m-2 d-1 and 15 MJ m-2 d-1, respectively. In this case, it was observed that the magnitude of the component values ​​of the radiation balance was mainly affected due to the cloudiness and changes in vegetation which mainly affected the levels of emittance and reflection surface. With regard to fractions of intercepted and absorbed photosynthetic active radiation, it was observed that they had daily average values ​​over the next years, which were equal to 0.69 and 0.64 in order. This data can be extremely useful for a better understanding of the interaction between the savanna and the atmosphere under natural climatic conditions. Keywords: radiation, net radiation, photosynthetically active radiation, Caatinga, dry.  

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.  

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 Red and Black Mulch Color Affects Production of Florida Strawberries

HortScience ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. 69-71 ◽  
Author(s):  
S.J. Locascio ◽  
J.P. Gilreath ◽  
S. Olson ◽  
C.M. Hutchinson ◽  
C.A. Chase
Keyword(s):  
Photosynthetically Active Radiation ◽  
Fruit Size ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Fragaria Ananassa ◽  
Active Radiation ◽  
Soil Temperatures ◽  
Marketable Fruit

Strawberries (Fragaria ×ananassa, Duch) were grown in the annual hill system at four locations in Florida to compare the effects of standard black low density polyethylene (LDPE) mulch and red reflective mulch (SMR-red) on fruit size and production. Marketable fruit size was not affected by mulch color. Early and total marketable fruit yields were not affected by mulch color at Bradenton, but yields were significantly higher at Gainesville with red than black mulch, and were significantly higher with black than red mulch at Quincy and Hastings. Soil temperatures under the black mulch were significantly higher than red mulch at Hastings but significantly higher under red than black mulch at Gainesville. Mean soil temperatures at soil depths of 5 to 25 cm ranged from 0.2 to 0.4 °C Reflected photosynthetically active radiation values at 25 and 50 cm above the mulch were higher earlier in the season and decreased as the season progressed. Within a month after transplanting when foliage covered about 10% of the mulch, reflections were lower and similar at both heights with black mulch than red and were higher at 25 than 50 cm with red mulch. Data indicate that there was not a consistent advantage of the use of this red mulch over black mulch at four locations in Florida.

scholarly journals Detrended Multiple Cross-Correlation Coefficient applied to solar radiation, air temperature and relative humidity

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Andrea de Almeida Brito ◽  
Heráclio Alves de Araújo ◽  
Gilney Figueira Zebende
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Solar Energy ◽  
Correlation Coefficient ◽  
Air Temperature ◽  
Cross Correlation ◽  
Global Solar Radiation ◽  
Meteorological Variables ◽  
Hourly Data ◽  
Cross Correlations

AbstractDue to the importance of generating energy sustainably, with the Sun being a large solar power plant for the Earth, we study the cross-correlations between the main meteorological variables (global solar radiation, air temperature, and relative air humidity) from a global cross-correlation perspective to efficiently capture solar energy. This is done initially between pairs of these variables, with the Detrended Cross-Correlation Coefficient, ρDCCA, and subsequently with the recently developed Multiple Detrended Cross-Correlation Coefficient, $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}$$DMCx2. We use the hourly data from three meteorological stations of the Brazilian Institute of Meteorology located in the state of Bahia (Brazil). Initially, with the original data, we set up a color map for each variable to show the time dynamics. After, ρDCCA was calculated, thus obtaining a positive value between the global solar radiation and air temperature, and a negative value between the global solar radiation and air relative humidity, for all time scales. Finally, for the first time, was applied $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}$$DMCx2 to analyze cross-correlations between three meteorological variables at the same time. On taking the global radiation as the dependent variable, and assuming that $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}={\bf{1}}$$DMCx2=1 (which varies from 0 to 1) is the ideal value for the capture of solar energy, our analysis finds some patterns (differences) involving these meteorological stations with a high intensity of annual solar radiation.

scholarly journals Photo-selective shade nets on the production and quality of sugarcane plantlets

2019 ◽  
Vol 23 (5) ◽  
pp. 366-371 ◽  
Author(s):  
José J. F. Cordeiro Júnior ◽  
Héliton Pandorfi ◽  
José A. D. Barbosa Filho ◽  
Alex S. Moraes ◽  
Luiz A. de Almeida Neto ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Substrate Temperature ◽  
Principal Component ◽  
Global Solar Radiation ◽  
Saccharum Officinarum ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Randomized Design ◽  
Completely Randomized Design

ABSTRACT Brazil is the world’s largest producer of sugarcane (Saccharum officinarum L.) and research aimed at propagation has promoted higher quality in production. The objective of this study was to investigate the effect of the variation of micrometeorological elements on the survival and quality of pre-sprouted sugarcane plantlets. The study was carried out in a protected environment (UFRPE). Plantlets of the cultivar RB92579 were obtained by the technique of production of pre-sprouted plantlets. The protected environments were divided into four modules covered with low-density polyethylene plastic + photo-selective shade nets and one module without shade net. Micrometeorological data of global and photosynthetically active solar radiation, air temperature, substrate temperature, relative humidity and the solar radiation spectrum were recorded in each module. The experiment was conducted in a completely randomized design and the principal component analysis was used to verify the association between the cultivation modules, micrometeorological variables and crop variables. Anti-UV low-density polyethylene plastic + freshnet led to lower transmittance of global solar radiation, higher percentage of photosynthetically active radiation and lower plantlet mortality. Substrate temperature above 30.2 °C resulted in higher plantlet mortality. Larger spectrum in the red range led to the production of better quality plantlet. The use of freshnet shade net promoted adequate conditions for the cultivation of sugarcane plantlets and allows obtaining better quality plantlets.

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