Relationships between yield and irrigation with low-quality water – a system approach

With the increasing usage of brackish water in agriculture there is a need to quantify the water quantity and quality relationship during irrigation of crops. A model based on a system approach was developed, where the responses of plants to water and salinity stress are expressed in a structural system of equations. The model was applied to field crops in the Israeli Negev, in three case studies, using existing linear and non-linear relationships between yield and irrigation and between yield and salinity. Model coefficients were estimated from experimental data. Model results were consistent with actual yield of corn and cotton in the single season cases. Simulation of wheat growing in the winter with supplemental irrigation with brackish water for 13 years showed interesting results of accumulation of soil salinity and reduction of yield. The model can be easily applied to other crops and growing areas. It can be used for analysis of long-term salinization processes.