Changes in evapotranspiration from an oil palm stand (Elaeis guineensis Jacq.) exposed to seasonal soil water deficits

Evapotranspiration (E) and interception losses (I(n)) from a stand of oil palm trees (Elaeis guineensis Jacq.) were measured weekly from 1988 to 1990 using a water balance method. Stomatal conductance, leaf area index and climatological parameters were measured and used to calculate the rate of transpiration (T) from canopy of oil palm stand using the Penman-Monteith equation. At high values of soil water storage in the root zone the evapotranspiration rate of the stand was 81% of the potential evaporation (E(p), PENMAN, 1948; modified by VAN BAVEL, 1966), the ratio of the transpiration rate to the potential evaporation (T/E(p)) varied from 0.69 to 0.72 and the stomatal conductance (g) varied from 6.0 to 6.6 mm.s-1. During the 1988 dry season, which was the more pronounced one, E/E(p) and T/E(p) were reduced to respectively 0.56 and 0.35. Net interception during rainy and dry seasons were respectively 11% and 5% of the potential evaporation. During the three dry seasons observed, the fraction of extractable water in the rooted zone of the soil (5.2 m deep) remained above 0.4 as a consequence of early stomatal closure which occurred when fractional extractable water of the top 80 cm of soil (f80) decreased below 0.67. When f80 decreased below 0.35, E/E(p) decreased sharply to a value of 0.1 corresponding to a stomatal conductance of about 1.5 mm.s-1 (Author's abstract)

Bibliographic Details

Main Authors:	Dufrêne, E., Dubos, Bernard, Rey, Hervé, Quencez, Pierre, Saugier, B.
Format:	article biblioteca
Language:	eng
Subjects:	F61 - Physiologie végétale - Nutrition, Elaeis guineensis, évapotranspiration, couvert, déficit d'humidité du sol, http://aims.fao.org/aos/agrovoc/c_2509, http://aims.fao.org/aos/agrovoc/c_2741, http://aims.fao.org/aos/agrovoc/c_1262, http://aims.fao.org/aos/agrovoc/c_25307,
Online Access:	http://agritrop.cirad.fr/392848/
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