ISHS Acta Horticulturae 449: II International Symposium on Irrigation of Horticultural Crops
HARGREAVES-SAMANI METHOD AND EVAPORATION PAN IN THE ESTIMATION OF REFERENCE EVAPOTRANSPIRATION |
| Authors: | F. La Loggia, M. Pennisi, V. Sardo |
| Keywords: | Class “A” pan, irrigation scheduling, historical data, data variability, climate changes |
| Abstract:
The availability of evaporation and temperature data during the irrigation season (June-September) for 13 years in a farm located in Eastern Sicily prompted a research aimed to compare the reference evapotranspiration (ETo) estimates obtained with the Hargreaves-Samani method (H-S) with those obtained through class A pan readings. Results showed the utility of averaging estimates obtained through the two methods when reference evapotranspiration exceeded 5–6 mm day-1. Weekly coefficients of variations for H-S were rather low, not substantially differing from those for larger intervals: this gives strength to the opinion that H-S can be used also for intervals less than the ten days recommended. Since deviations in single years' monthly estimates from the 13-years averaged values were within narrow limits, it may be concluded that averaging "historical" values of H-S and class “A” pan for a period of (at least) a similar length -13 years- may yield a useful forecasting tool for water management in the particular environment. Even in the absence of class “A” data, H-S alone may be useful in irrigation scheduling. Due to its structure H-S may be employed to model changes in ETo depending on climate modifications. | |
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