1 Water Saving in the Yellow River Basin, China. 1. Irrigation Demand Scheduling A. A Campos1, L S. Pereira1, J.M. Gonçalves1, M. S. Fabião1, Y. Liu2, Y. N. Li2, Z. Mao3, B. Dong3 1Center for Agricultural Engineering Research, Institute of Agronomy, Technical University of Lisbon, Tapada da Ajuda, 1349-017 Lisbon, Portugal,
[email protected] 2China Institute for Water Resources and Hydropower Research, Beijing, China,
[email protected],
[email protected] 3Department of Irrigation and Drainage, College of Water Resources and Hydropower, University of Wuhan, China,
[email protected] ABSTRACT Water saving in irrigation is a main issue in the Yellow River basin. Field studies were conducted in two areas: The Huinong Irrigation District (HID), Ningxia Province, in the upper reaches, where excess irrigation water is applied giving rise to water-logging and salinity problems, and the Bojili Irrigation District (BID), Shandong Province, in the lower reaches of the river basin, where water availability is insufficient and salinity is related to drainage reuse. To control such problems, improved irrigation scheduling may play an important role. The irrigation scheduling simulation model ISAREG was used to evaluate the current schedules and to generate improved ones. It computes the capillary rise from the watertable and deep percolation when excess water is applied, and considers the effects of salinity in crop evapotranspiration, crop water stress and yields, as well as the leaching requirements. The model has been previously calibrated and validated for North China. The model has been explored interactively with surface irrigation simulation models to consider the limitations imposed by the field systems concerning depths to be applied and irrigation performances.