Relações de dependência entre fluxos de CO2 e variáveis meteorológicas na cultura de milho (Zea mays L.)

• Autor(a) principal: Andrade, Vanda Maria Sales de
• Data de Publicação: 2009
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1506
• topic: Fluxos de CO2; Eddy covariance; Milho BR106; Fluxes of CO2; Eddy covariance; Corn BR106; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::AGROMETEOROLOGIA

A micrometeorological study was conducted at the experimental farm of EMBRAPA/CNPMS in Sete Lagoas, Minas Gerais, Brazil, from October 2008 to February 2009 to quantify the diurnal and nocturnal variations of concentrations and fluxes of CO2 amongst a maize crop and atmosphere, using the technique of Eddy Covariance. There had been used meteorological variables relevant to changes in CO2 streams, such as net radiation, photosynthetically active radiation (RFA), solar radiation (Rg), air temperature (Tar), vapor pressure deficit (DPV), wind speed (VV), rainfall (PRP) and temperature (Tsolo) and soil moisture (Usolo), to establish dependency relationships between the magnitude of flows and CO2 during the phenological stages of crop and the relevant meteorological variables. The daily average CO2 concentrations ranged from 369 to 414 ppm, with an average value of 391 ppm within the period from October 2008 to February 2009. Nocturnal CO2 concentrations ranged from 394 to 454 ppm, averaging 415 ppm. The average hourly concentrations of CO2 ranged from 385 ppm (daytime) to 437 ppm. The average flow of CO2 during the daytime was -7.53 mmol.m-2.s-1. The behavior of nocturnal CO2 fluxes, which represent the contributions of soil respiration, of roots and shoots, ranged from 1.69 to 2.35 mmol.m-2.s-1. The net radiation and photosynthetically active radiation were the variables that presented higher correlation with the diurnal pattern of CO2.