Evapotranspiration rates of Eichhornia crassipes (Mart.) Solms, Salvinia molesta d.s. Mitchell and Nymphaea lotus (L.) Willd. Linn. in a humid tropical climate
1988; Elsevier BV; Volume: 30; Issue: 3 Linguagem: Inglês
10.1016/0304-3770(88)90052-6
ISSN1879-1522
Autores Tópico(s)Hydrology and Sediment Transport Processes
ResumoUnder humid tropical conditions at Kottamparamba (11° 15′ N; 75° 52′ E; height 70 m above m.s.l.), the evapotranspiration rates of Eichhornia crassipes (Mart) Salvinia molesta D.S. Mitchell and Nymphaea lotus (L.) Willd. were 3.8–10.5, 2.1–6.8 and 2.5–6.0 mm day−1, respectively, compared to the open water evaporation of 2.1–7.1 mm day−1. Daily evapotranspiration was recorded for plants grown in 1-m3 fiberglass tanks from 1983 to 1985, whilst leaf area indices were maintained at a constant level. The ratios of evapotranspiration to open water evaporation were 1.30–1.96 for Eichhornia crassipes, 0.96–1.39 for Salvinia molesta and 0.82–1.35 for Nymphaea lotus. During the dry period (November-May), Eichhornia crassipes enhanced water losses by 32–51%, whereas Nymphaea lotus retarded losses by 5–18%. In wet periods (June-October), all the plants under study enhanced water losses. Quantitatively, the presence of Eichhornia crassipes increased the water losses by 750 mm year−1, whereas Nymphaea lotus saved 145 mm year−1. Evapotranspiration of these aquatic plants significantly correlated with solar radiation, relative humidity and wind speeds. The albedo under these aquatic plants ranged from 0.12 to 0.20 compared to that of open water at 0.09 to 0.13. The estimated evapotranspiration of Eichhornia crassipes using the Penman-Montieth equation was lower than the measured values by 35%, whilst estimates for Salvinia molesta and Nymphaea lotus were only 12–13% lower.
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