| An irrigation scheduling model was constructed. It combines models for crop ground cover development, soil evaporation, plant transpiration, root growth, root water uptake and soil water movement. Potential evapotranspiration (ET;The irrigation scheduling model is a soil water budget model based on the soil-plant-atmospheric continuum theory. It was developed for three crops: cotton, tomato and corn, three soils, and a range of sowing dates and planting densities. Models for root growth, root water uptake and soil water movement were adapted from the literature. Simulated leaf water potential served as guideline for establishing minimum soil water contents to trigger irrigation.;A Box-Jenkins ARIMA (1,1,0) model was identified for daily ET;The dynamic programming model minimizes daily average conjunctive water demand of several fields, of different sizes and soils, planted with different crops, by selecting sowing dates that originate irrigation programs with complementary (non-coincidental) irrigation dates. Monte Carlo simulations of the model, using the ARIMA ET;Experimental work was done for the purpose of validating or improving simulation models. Lysimeters data collected hourly were used for simulation. A crop ground cover development model driven by time that allows for adjustments in planting density was modified using thermal as a driver, and was found to simulate well data of several authors. Evapotranspiration (ET) of several crops were measured on lysimeters. An ET model that combined models for soil evaporation and canopy radiation interception simulated the results closely, before senescence. During senescence, crop ET stayed close to ET... |
