Medidas radiométricas em casas de vegetação com cobertura plástica na região de Campinas - SP

Abstract

RESUMO:Com o objetivo de caracterizar as relações e alterações radiométricas em três casas de vegetação, cobertas com filme transparente de polietileno de baixa densidade (PEBD) de camada simples com 150µm de espessura, tratado contra raios ultravioleta, sob ambientes distintos, foram realizados os experimentos durante o cultivo hidropônico de alface, cultivar Vera, na região de Campinas -SP, em diferentes períodos do ano, visando ao uso de dados experimentais de postos meteorológicos em substituição à necessidade de adquirir equipamentos de radiação para medições internas. As casas de vegetação eram de estrutura metálica de aço, de forma e volume idênticos. Coletaram-se a radiação solar global interna e externa (RSGI e RSGE, W m -2 ), a radiação fotossinteticamente ativa (RFA, mol m -2 s -1 ) e a radiação ultravioleta, em 254; 312 e 365 nm (RUV, W m -2 ). Os resultados mostraram que as equações de regressão linear são estimativas aceitáveis na obtenção da radiação fotossinteticamente ativa em função da radiação solar global externa. Em ambientes fechados e climatizados, existe maior correlação entre a radiação fotossinteticamente ativa e a radiação solar global externa. A orientação das casas de vegetação não climatizadas não influencia no espalhamento interno da radiação fotossinteticamente ativa. PALAVRAS-CHAVE:ambiente protegido, climatização, polietileno de baixa densidade, radiação solar. RADIOMETRIC MEASUREMENT OF GREENHOUSES WITH PLASTIC COVER AT CAMPINAS REGION-SP ABSTRACT:The objective of this study was to characterize the radiometric relationship and changing in three greenhouses covered with transparent low density polyethylene film (PEBD) with a 150m single layer of low density polyethylene film, treated with compounds that inhibit rapid degradation by ultraviolet radiation, under effects of different environments. The experiments were conducted during hydroponics lettuce production of Vera variety at Campinas region-SP in different periods of the year, aiming the use of experimental data from meteorological stations in substitution of the needs to pursue radiometric equipments for internal measurements. Three identical greenhouses, in shape and volume, with steel metal structure were used. Data of internal and external global solar radiation (RSGI and RSGE, W m 2 ), photosynthetically active radiation (RFA, mol m -2 s -1 ), and ultraviolet radiation in 254; 312 e 365 nm (RUV, W m -2 ) were collected. The results showed that the linear regression equations are acceptable to estimate the photosynthetically active radiation based on the external global solar radiation. Closed acclimatized greenhouses show better statistical correlation between the photosynthetically active radiation and the external global solar radiation. The orientation of non acclimatized greenhouses does not influence the internal scattering of photosynthetically active radiation.

Produção de mudas de melancia em diferentes ambientes e de frutos a campo

“…No presente estudo, a luz transmitida pelo polietileno de baixa densidade (plástico) para o interior do ambiente, em termos de fluxo de fótons fotossintéticos (RFA), foi aproximadamente, 551,52 µmol m -2 s -1 , segundo cálculo realizado a partir dos dados de radiação global externa, empregando-se a equação de Costa & Leal (2011), definida por RFA = 1,0798*RGE + 114,6, onde RGE é a radiação global externa. O cálculo foi realizado considerandose que na época do ano em que o experimento foi conduzido e para ambientes cobertos com filme de polietileno de baixa densidade, as equações de regres-são linear são estimativas aceitáveis na obtenção da radiação fotossinteticamente ativa em função da radiação solar global externa, e independe da orientação das casas de vegetação (Costa & Leal, 2011).…”

Volume of polyethylene bags for development of papaya seedlings in protected environments

“…The roofing material was one of the factors that affected the growth and development of papaya seedlings, together with the volumes of the containers. These materials induced variations in the internal microclimate of the protected environments, especially in its attenuating solar radiation and spectral distribution (COSTA & LEAL, 2011), which was 1,161.2 kJ m -2 , as well as the use of lateral screens in the distribution of environment internal temperature (DUARTE et al, 2011).…”

Micrometeorological Characterization of Protected Environments for Plant Production

“…These studies often involved energy balance, radiation and/or mass balance, such as the environmental modification caused by low perforated polyethylene tunnels in lettuce growth (Buriol et al, 1993a), the meteorological elements in a plastic greenhouse in Pelotas-RS (Camacho et al, 1995), the protected cultivation and microclimatic aspects (Sentelhas and Santos, 1995), the energy balance in pepper plants under protected and field cultivation (Cunha et al, 2001), the energy balance in the cucumber crop in a natural and protected environment , the radiation balance and heat flux in the soil in a natural and protected environment with cucumber cultivation , the estimation of the latent heat flux by the energy balance in pepper protected cultivation (Cunha et al, 2002), the micrometeorological alterations caused by the plastic greenhouse and its effects on the pepper crop growth and production (Cunha and Escobedo, 2003 ), the use of meshes and shading in a protected environment and on the growth and commercial production of Gerbera jamesonii (Guiselini et al, 2004a), the effect of the protected environment cultivated with melon on the meteorological elements and its relationship with external conditions (Vásquez et al, 2005), the microclimate of vineyards cultivated under plastic cover and full sun (Lulu e Pedro Júnior, 2006), the microclimatic characterization of coffee trees cultivated under shading mesh and in full sun (Morais et al, 2007), the study of microclimate simulations in greenhouses aiming at the acclimatization of micropropagated banana plantlets cv Grande Naine (Scaranari et al, 2008), micrometeorological changes in vineyards by using plastic covers (Cardoso et al, 2008), the management of solar radiation coverage of protected environments and its effects on gerbera production (Guiselini et al, 2010), models for estimating micrometeorological elements in a protected environment (Costa et al, 2011), the efficiency of heat-reflective and shading screens in a screen-like protected environment under high temperatures (Rampazzo et al, 2014), agricultural screens as an undercover in the cultivation of hydroponic lettuce (Sales et al, 2014), the use of thermoreflective screen in protected environments for tomato cultivation (Ferrari and Leal, 2015), solar radiation and air temperature in a protected environment (Rebouças et al, 2015) and the monitoring of micrometeorological variables in different protected environments in the winter period ( Paula et al, 2017).…”

“…Aspects like changes in the radiation balance in a protected environment with light-diffusing polyethylene cover (Sousa et al, 2005), solar radiation in protected environments cultivated with tomato in the summer-autumn seasons of Rio Grande do Sul (Beckmann et al, 2006), and the ratio between photosynthetically active radiation and global radiation in greenhouse tomato cultivation (Steidle Neto et al, 2008) were presented. Furthermore, luminosity in protected cultivation environments (Santos et al, 2010), radiometric measurements in greenhouses with plastic cover in the Campinas-SP region (Costa and Leal, 2011), and components of solar radiation in tomato cultivation under protected environment conditions (Reis et al, 2012) were also widely investigated.…”