Consulta: subjectFacets:"Heat pulse"
Registros recuperados: 2
Data/hora: 12/06/2024 15:49:42

SUNLIT AND SHADED MAIZE CANOPY WATER LOSS UNDER VARIED WATER STRESS
Provedor de dados: 91
Autores: Santos,Antonio Odair; Bergamaschi,Homero; Fuchs,Marcel; Rosa,Luís Mauro G.; Bergonci,João Ito.
ABSTRACT The precise estimation of transpiration from plant canopies is important for the monitoring of crop water use and management of many agricultural operations related to water use planning. The aim of this study was to estimate transpiration from sunlit and shaded fractions of a maize ( Zea mays L.) canopy, using the Penman-Monteith energy balance equation with modifications introduced by Fuchs et al. (1987) and Fuchs &amp; Cohen (1989). Estimated values were validated by a heat pulse system, which was used to measure stem sap flow and by a weighing lysimeter. A relationship between incident radiation and leaf stomatal conductance for critical levels of leaf water potential was used to estimate transpiration. Results showed that computed...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Transpiration; Penman-Monteith; Heat pulse; Zea mays L.
Ano: 1999
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43661999000300261

ASSESSMENT OF CORN WATER UPTAKE BASED ON SAP HEAT TRACING UNDER WATER-STRESSED CONDITIONS
Provedor de dados: 91
Autores: Santos,Antonio Odair; Bergamaschi,Homero; Rosa,Luís M. G.; Bergonci,João I.; Radin,Bernadete.
ABSTRACT Crop water monitoring is an important aspect for precise control of irrigation. A reliable and movable technique is needed to properly assess water uptake of crops in the field. Water uptake by field grown maize ( Zea mays L.), in water-limited conditions was verified with the heat pulse system. The temperature difference between two radially inserted thermocouples, one 9 mm above and the other 4 mm below a heater piercing the maize stem, was measured every 0.3 sec following emission of a heat pulse in conditions of varied atmospheric demand. Comparisons of heat pulse system outputs and a high precision transpiration model estimates were done on hourly and daily basis, when low sap velocities were expected to occur. Hourly and daily basis of the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sap flow; Transpiration; Water stress; Heat pulse.
Ano: 1999
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43661999000200145