Stem heat balance method to estimate transpiration of young orange and mango plants

Abstract

The present study had as its main objective the evaluation of the heat balance method in young orange and mango plants under protected environment. The work was carried out at Embrapa Cassava and Tropical Fruits, Cruz das Almas, BA. Later on, estimates of sap flow were conducted for two mango plants cultivated in pots of 15 and 50 L installed on weighting platforms of 45 and 140 kg; sap flow was determined in three orange plants, two of which were also installed on weighing platforms. The values of sap flow were compared to the transpiration measured by lysimeters at integrated intervals of 1, 2, 4 and 24 h. The heat balance method showed good precision for estimating daily transpiration (R 2 = 0.95 and R 2 = 0.90), accompaning the availability of energy in the system, underestimating on average 4.6% of the daily transpiration in orange plants and overestimating in about 0.3% the daily transpiration of mango plants under conditions of good water supply. The heat balance method underestimated by 16% the transpiration in orange under conditions of water deficit.

Transpiração de plantas jovens de laranjeira 'valência' sob porta-enxerto limão'cravo' e citrumelo 'swingle' em dois tipos de solo

“…Grande parte dos estudos sobre medidas de transpiração de plantas, principalmente em frutíferas lenhosas, baseia-se em métodos de fornecimento de calor no tronco. Em citros, medições de fluxo de seiva têm sido utilizadas em vários trabalhos ligados ao consumo de água pela planta e fisiologia do estresse (ORTUÑO et al, 2007;VASCONCELOS et al, 2010;VELLAME et al, 2010). A estimativa da transpiração com base nesses métodos pressupõe a equivalência entre o fluxo de seiva no tronco e o fluxo transpiratório nas superfícies foliares, pressuposto válido quando se considera o fluxo em escala diária (DELGADO-ROJAS et al, 2007;VELLAME et al, 2009;VELLAME et al, 2010).…”

Time lag characteristics of sap flow in seed-maize and their implications for modeling transpiration in an arid region of Northwest China

“…With the advantages of easy application and no calibration, the stem heat balance technique is widely used to measure the stem sap flow (Dzikiti et al, 2007;Vellame et al, 2010;Chirino et al, 2011;Swaef et al, 2012). Stem sap flow can directly indicate instantaneous water consumption (Sakuratani, 1981;Baker and van Bavel, 1987;Steppe et al, 2010), canopy transpiration, and hydraulic conductance (Martin et al, 2001).…”

Método de dissipação térmica para determinação do fluxo de seiva em coqueiro anão-verde

“…Em cultivos do tipo pomar, nos quais a cobertura do solo é descontínua, a transpiração é o principal elemento da evapotranspiração (Vellame et al, 2010).…”