EVALUATION AND IMPROVEMENT OF FIELD IRRIGATION TECHNIQUES FOR AN IRRIGATION DISTRICT AT LOWER REACHES OF THE YELLOW RIVER

摘要

Two typical experiment areas were selected which represent respectively upstream and downstream conditions in the Bojili Irrigation District. Field irrigation experiments were conducted for winter wheat and summer maize over two consecutive years. All the experiments were simulated by SRFR model that is a computer program for simulating the flow in surface irrigation. The infiltration parameters were calibrated and the model was validated from the simulations. Three methods were compared for determination of field application efficiency (Ea) and irrigation uniformity (Du). Existing irrigation performance was evaluated based on calculated Ea and Du for each irrigation. Different improvement scenarios were compared from the simulation results by SRFR for different conditions in the upstream and downstream of the Irrigation District. Some recommendations were suggested for improvement of the irrigation performance. In upstream area, the application efficiency can be increased from current 0.7 to 0.84 by land leveling and reducing the slope of the irrigation borders. In downstream area, the Ea can be increased from current 0.64 to 0.8 by land leveling and cutting existing large borders longer than 200 m into small borders, each not longer than 140 m.