A Holistic Generic Integrated Approach for Irrigation, Crop and Field Management: The SALTMED Model

R. RAGAB
Centre for Ecology & Hydrology, Wallingford, OX10 8BB, UK
E-mail: Rag@ceh.ac.uk

ABSTRACT

A successful water management scheme for irrigated crops requires an integrated approach that accounts for water, crop, soil and field management. Most existing models are designed for a specific irrigation system, specific process such as water and solute movement, infiltration, leaching or water uptake by plant roots or a combination of them. There is a serious gap in the knowledge related to models of a generic nature, models that can be used for a variety of irrigation systems, soil types, soil stratifications, crops and trees, water application strategies (blending or cyclic), leaching requirements and water qualities. SALTMED model has been developed to fill this gap. The model employs established water and solute transport, evapotranspiration and crop water uptake equations. Due to the scarcity of data sets that are suitable for model testing over the complete growing season, where different processes are acting simultaneously, different subroutines were separately tested. The model was able to reproduce the soil moisture, salinity and relative concentration profiles of Gilat Loam under infiltration using trickle line source, soil moisture profiles of sand under trickle line source and soil moisture profile of Lakeland Sand (3 layers) under infiltration from trickle point source. In this paper, the model has been run with five examples of applications for one growing season using data from the literature. The model successfully illustrated the effect of the irrigation system, the soil type, the irrigation salinity level on soil moisture and salinity distribution, leaching requirements, and crop yield in all cases.