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| Author(s): |
Roberto Terumi Atarassi
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2005-01-19 |
| Examining board members: |
Marcos Vinicius Folegatti;
João Francisco Escobedo;
Nilson Augusto Villa Nova;
Paulo Cesar Sentelhas;
Enio Farias de Franca e Silva
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| Advisor: | Marcos Vinicius Folegatti |
| Abstract | |
In a greenhouse production system, the canopy of culture is the main element that modifies the internal microclimate. Its comprehension is very important to understand the energy exchange process. Due to the complexity interaction among several elements, the modeling represents an important tool for research in protected environments, but little used in Brazil. The aim of the present work was to develop a simulation model for estimating the components of canopy energy balance of sweet pepper crop cultivated in greenhouse and its calibration and test with experimental data. It was developed a steady-state model divided in four submodels: latent heat flux (λE), sensible heat flux (H), short wave balance (BOC) and long wave balance (BOL). The λE and H submodels were based on the mixed convection mass and heat transfer theory, associated with equation to leaf stomatal resistance estimation using climatic data. The BOC and BOL submodels considered the row orientation of crop, partial cover of soil and leaf area index (IAF). The model was implemented in a Microsoft EXCEL 2000 and solved numerically with routine developed in VBA language (Visual Basic for Application) The model was calibrated and tested with experimental data from a greenhouse 17,5m long by 6,4m width, 3,0m height, localized in Piracicaba City, São Paulo, Brazil, in experimental area of "LUIZ DE QUEIROZ" College Of Agriculture - São Paulo University (USP), cultivated with sweet pepper crop, in single row, spaced in 1,2m x 0,5m. It was taken measurements of transpiration from load cells weighting lysimeter, global, diffuse and PAR radiation, wind velocity, temperature and actual vapor pressure and canopy temperature. Also was taken measurements of leaf area index, height and diameter of plant. The model was test after calibration with experimental data. The model didnt estimate precisely the components of energy balance, but it was capable to follow the variation of measured data in different proportion and indicating the necessity of better calibration, especially concerned with extinction coefficients of the canopy. The modeling allowed verifying approach limitations founded in literature and used in present model, like the determination of aerodynamic and stomatal resistances. (AU) | |