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Abstract
Frisina V.A., Escobedo J.F., Gomes E.N. Estimativa da radiação fotossinteticamente ativa (PAR) em estufa de polietileno. In: Proceedings of the 3. Encontro de Energia no Meio Rural [Proceedings online]; 2000 Sep 12-15; Campinas, SP, Brazil. 2003 [cited 2024 May 05]. Available from: URL: http://www.proceedings.scielo.br/scielo.php?script=sci_arttext&pid=MSC0000000022000000200056&lng=en&nrm=van .
This paper presents a simple linear regression to estimate the active photosynthetic radiation inside a poliethylene greenhouse (PARin) as function of the external values (PARex). The radiations have been measured at Solar Radiometric Station, UNESP, Botucatu-SP, Brazil, inside a polyethylene greenhouse (100mm) and in a external area. Photosynthetically active photon flux density was measured by means of two LI-COR model quantum sensors installed out and inside the greenhouse. The database have included instantaneous values of irradiations (W/m2) and daily irradiations (MJ/m2) measured between June 1999 to November 1999. In the data acquisition it was utilized a Datalogger Campbell 21X operating at 1 Hz frequency and storing 5 minute averages. The results showed that PAR can be estimated inside a polyethylene greenhouse (PARin) as function of the external PAR measurements (PARex) with high correlation coefficient of the linear regression. The following equations have been obtained: PARin = 4,629 + 0,603 PARex with R = 95,98% to the instantaneous measurements and PARin = 0,830 + 0,527 PARex with R = 97,84% to the daily measurements.
Keywords : radiação fotossinteticamente ativa; estimativa; estufa de polietileno.