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Search Results: 1 - 6 of 6 matches for " Tazzo "
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Relationships of photosynthetic photon flux density, air temperature and humidity with tomato leaf diffusive conductance and temperature
Righi, Evandro Zanini;Buriol, Galileo Adeli;Angelocci, Luiz Roberto;Heldwein, Arno Bernardo;Tazzo, Ivonete Fátima;
Brazilian Archives of Biology and Technology , 2012, DOI: 10.1590/S1516-89132012000300005
Abstract: the objective was to study the leaf temperature (lt) and leaf diffusive vapor conductance (gs) responses to temperature, humidity and incident flux density of photosynthetically active photons (ppfd) of tomato plants grown without water restriction in a plastic greenhouse in santa maria, rs, brazil. the plants were grown in substrate and irrigated daily. the gs was measured using a steady-state null-balance porometer on the abaxial face of the leaves during the daytime. both leaf surfaces were measured in one day. the ppfd and lt were measured using the porometer. leaf temperature was determined using an infrared thermometer, and air temperature and humidity were measured using a thermohygrograph. the leaves on the upper layer of the plants had higher gs than the lower layer. the relationship between the gs and ppfd was different for the two layers in the plants. a consistent relationship between the gs and atmospheric water demand was observed only in the lower layer. the lt tended to be lower than the air temperature. the mean value for the gs was 2.88 times higher on the abaxial than adaxial leaf surface.
Emiss?o e expans?o foliar em três genótipos de tomateiro (Lycopersicon esculentum Mill.)
Pivetta, Carina Rejane;Tazzo, Ivonete Fatima;Maass, Guilherme Fabiano;Streck, Nereu Augusto;Heldwein, Arno Bernardo;
Ciência Rural , 2007, DOI: 10.1590/S0103-84782007000500009
Abstract: this study was aimed at estimating the phyllochron on the main stem and on first order lateral branches, and estimate leaf area from leaf number in three tomato genotypes grown inside a plastic green-house. an experiment was conducted inside a plastic greenhouse at the experimental area of the plant science department of the federal university of santa maria, santa maria, rs, brazil. three tomato genotypes were used: 'kátia', 'durino', and 'emperor'. three to four-leaf seedlings were transplanted on 10/31/2005. the experimental design was a complete randomized block with four replications composed of two 8-plants rows. the number of leaves on the main stem and on first order lateral branches was counted in six plants of each replication. leaf length and width were measured on two plants per replication. the phyllochron was estimated as the inverse of the slope of the linear regression of leaf number against accumulated thermal time from transplanting. the phyllochron on the main stem was greater than on the first order lateral branches. leaf area on a stem of the tomato plant can be estimated from the number of accumulated lateral leaves on this stem.
Evapotranspira??o do piment?o em estufa plástica estimada com dados meteorológicos externos, na primavera
Tazzo, Ivonete F.;Heldwein, Arno B.;Maldaner, Ivan C.;Pivetta, Carina R.;Streck, Luciano;Righi, Evandro Z.;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2012, DOI: 10.1590/S1415-43662012000300007
Abstract: the objective of this work was to develop, test and validate mathematical models for maximum evapotranspiration estimations of a sweet pepper crop using meteorological variables measured outside the greenhouse, in santa maria, rs. two experiments were conducted during spring of 2005 and 2006, for data collection, respectively for development and testing of models. the maximum evapotranspiration was measured using three drainage and one weighting lysimeter. plant height, number of leaves and leaf area were weekly determined. the daily values of meteorological variables were obtained at the main meteorological station of santa maria. it is possible to estimate the maximum evapotranspiration of sweet pepper crop grown inside greenhouses during the spring with mathematical models that use various external measurements. better estimations of maximum evapotranspiration of sweet pepper crop grown inside plastic greenhouse during the spring were obtained using meteorological variables, mean vapor pressure deficit, solar radiation, net radiation and reference evapotranspiration, measured outside the greenhouse. it was concluded that it is possible to estimate, with acceptable accuracy at daily level, the maximum crop evapotranspiration of sweet pepper grown in greenhouse in spring, using complex mathematical models that use meteorological variables measured outside the greenhouse.
Varia??o vertical da temperatura do ar no dossel de plantas de batata
Tazzo, Ivonete F.;Heldwein, Arno B.;Streck, Luciano;Trentin, Gustavo;Grimm, Edenir L.;Maass, Guilherme F.;Maldaner, Ivan C.;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2008, DOI: 10.1590/S1415-43662008000500007
Abstract: air temperature is one of the most important meteorological elements in the conditioning of infection caused by pathogens. the objective of this study was to determine the variation of air temperature in the canopy of potato plants, cv. macaca. two experiments were carried out, one in the spring in a rural farm in the county of silveira martins, rs, from october 15 to december 5, 2003, and the second in the autumn in the experimental area of the crop production department of universidade federal de santa maria, rs, from march 27 to june 8, 2004. a tower with five levels of continuous psicrometric measurements and three psicrometer repetitions was installed at the half height of the plants and at 1.0 m height. each psicrometric couple consisted of two platinum resistance thermometers (pt - 100), installed inside mini-shelters. the sensors were plugged into a datalogger, the means at 10 min intervals being continually stored. the mean differences of temperature (t2.2 - t0.15) in the experimental period in the spring of 2003 were -1.72 oc during the day (11:00 to 17:00 o'clock) and +0.82 oc during the night (21:00 to 4:00 o'clock). in 2004 the mean differences of temperature (t2.0 - t0.10) were -1.12 oc during the day and -0.62 oc during the night. the mean temperature of the day was larger in the inferior levels of the canopy, being the gradients of air temperature more accentuated during the day period than in the night.
Evapotranspira??o máxima do piment?o cultivado em estufa plástica em fun??o de variáveis fenométricas e meteorológicas
Pivetta, Carina R.;Heldwein, Arno B.;Maldaner, Ivan C.;Radons, Sidinei Z.;Tazzo, Ivonete F.;Lucas, Dionéia D.;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2010, DOI: 10.1590/S1415-43662010000700013
Abstract: the objective of this study was to estimate maximum evapotranspiration (etm) of sweet pepper inside a plastic greenhouse as a function of evaporation measured with "piche" evaporimeter (epi) exposed to solar radiation, with and without easily measured meteorological and phenologic variables. the experiment was carried out inside a 240 m2 plastic greenhouse. daily etm (measured with drainage lysimeters), epi, air temperature, vapor pressure deficit (di), leaf area index (lai), plant height (ph), and leaf number (ln) were measured. models were fitted to estimate etm using data collected on even days of the experimental period, selecting only models with parameters significant at 5% by t test and coefficient of determination (r2) > 0.80. the best models for estimating etm were obtained with epi values, associated with a plant growth parameter, such as lai, ln and ph. it was possible to estimate etm of sweet pepper crop with acceptable accuracy (r2 between 0.81 and 0.91) to perform irrigation inside plastic greenhouse using models that take into account epi and at least one plant growth parameter, however models with ph should be preferred. including di measured at 9 h in the models with epi and ph or nl or lai improved etm estimates.
Evapotranspira??o máxima do tomateiro sob estufa plástica em fun??o de variáveis fenométricas e meteorológicas
Pivetta, Carina Rejane;Heldwein, Arno Bernardo;Tazzo, Ivonete Fátima;Maldaner, Ivan Carlos;Dalbianco, Leandro;Streck, Nereu Augusto;Machado, Rui Manuel Almeida;
Bragantia , 2011, DOI: 10.1590/S0006-87052011000300029
Abstract: the objective of this study was to estimate the maximum evapotranspiration (etm) of tomato inside greenhouse as a function of evaporation measured with "piche" evaporimeter exposed to solar radiation (epi) with and without easily measured meteorological and phenological variables during the 2005 spring growing season. daily etm (measured with drainage lysimeters), epi, air temperature, air vapor pressure deficit (d), leaf area index (lai), plant height (ph), and number of leaves (ln) were measured. models were fitted to estimate etm using data collected on even days of the experimental period. in the multiple regression analysis only models with parameters significant at 5% by t test and coefficient of determination (r2) greater than 0.85 were selected. models were evaluated with independent data collected on odd days of the period. statistics used for model evaluation were regression analyses between observed and estimated data, root mean square error (rmse), and accuracy (r), agreement (d) and confidence (c) indices. results showed that it is possible to estimate etm of tomato crop with acceptable accuracy (r2 between 0.87 e 0.92) to perform irrigation inside plastic greenhouse using models that take into account epi and at least one plant growth parameter; models with ph should be preferred. including d measured at 9 h in the models with epi and ln or ph or lai improved etm estimates.
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