ISHS Acta Horticulturae 664: IV International Symposium on Irrigation of Horticultural Crops
CONSUMPTIVE USE PROGRAM (CUP) MODEL |
| Authors: | M.N. Orange, J. Scott Matyac, R.L. Snyder |
| Keywords: | Evapotranspiration, Crop Coefficients, Crop Water Requirements |
| Abstract:
A user-friendly Excel application program (CUP) was developed to improve the dissemination of Kc and crop evapotranspiration (ETc) information to California growers and water purveyors. CUP computes reference evapotranspiration (ETo) from monthly means of solar radiation, maximum and minimum temperature, dew point temperature, and wind speed using the daily Penman-Monteith equation. The program uses a curve fitting technique to drive one year of daily weather and ETo data from the monthly data. In addition, daily rainfall data are used to estimate bare soil evaporation as a function of mean of ETo and wetting frequency in days. A bare soil Kc value is calculated to estimate the off-season evapotranspiration and as a baseline for in-season Kc calculations. CUP accounts for the influence of orchard cover crops on Kc values and it accounts for immaturity effects on Kc values for tree and vine crops. Further, the program computes and applies all ETo and Kc values on a daily basis to determine crop water requirements by month, by season, by year. The application outputs a wide range of tables and charts that are useful for irrigation planning. This paper presents the advantages of CUP. | |
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