Strategies of Irrigation Scheduling and Water Balance foran Irrigation District at Lower Reaches of the Yellow River

摘要

Two typical experimental areas were selected to represent respectively upstream anddownstream conditions in the Bojili Irrigation District. Field observations were conducted forwinter wheat and summer maize in two consecutive years. All the experiments were simulatedwith the ISAREG model, that is an irrigation-scheduling simulation model based on the soil waterbalance. The model was validated from these simulations. Current irrigation scheduling wasevaluated based on the simulation results. Two irrigation-scheduling strategies for 10 crops infour typical years (probability of 25%, 50%, 75% and 90%) in three counties were compared bythe model simulations. The field irrigation demand hydrographs for different strategies werecalculated and water balance between supply and demand were analyzed for the wholeIrrigation District. Results of these studies show that the water balance could be satisfied in theaverage year when both the improved irrigation techniques and controlled deficit irrigation wereadopted in the Irrigation District.