ISHS Acta Horticulturae 278: Symposium on Scheduling of Irrigation for Vegetable Crops under Field Condition
A DISCRETE TIME NUMERICAL MODEL FOR IRRIGATION SCHEDULING |
| Authors: | M.N. Nimah, Z. Khallouf |
| Abstract:
A mathematical model was developed to schedule irrigation for field crops using weather, soil and crop data. The crop data considered were root development function, planting and harvesting date, growth stage, and tolerance to water and salt stresses. Crop coefficients were estimated with an empirical equation involving stress coefficient and evaporation coefficient. Weather data included measured daily and/or monthly maximum and minimum temperature and extraterrestrial radiation and estimates of other factors. The model selects among six methods to estimate potential evapotranspiration depending on availability of waeather data. Soil data considered were soil water retention properties, soil salinity and soil variability and type. A computer program adaptable to microcomputers (CPU>64K) was subsequently developed for predicting soil water storage and irrigation depth and time. The schedule of irrigation may be adjusted any time during the growing season by using field feed back soil moisture information. The program was tested utilizing data reported by FAO and literature. The test results indicated good agreement between the model predictions and reported values. | |
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