LAUSR

Estimation of electrical conductivity (EC) in nutritive solutions is generally used to evaluate its suitability for irrigation. EC is a measure of osmotic potential of water applied via irrigation which affects growth and yield of irrigated crops. Generally, the estimation is achieved multiplying the total mass concentration by an empirical coefficient linearly relating it to EC. Different electrolytes with equal mass concentration induce different electrical conductivities which lead to inaccuracy when estimating EC of multiple salts in solution. The article presents the rationale and derivation of a model relating partial mass concentration (NSC) of several nutritive salts (NS) in solution to its resulting EC and ratio of nutritive elements (NE). Partial mass concentration of eight nutritive salts used in the composition of nutritive solutions has been co-related to resulting EC. Individual co-relations led to nonlinear regressions resulting in eight polynomial equations combined in a multivariable function describing EC in terms of NSC. Nutrient concentration NC (considering multiple NE in solution) and its resulting EC are described by a model relating them to NSC: (EC, NC1, NC2,… NCn) = f(NSC1, NSC2,…, NSCn). The model estimates EC with considerable accuracy (co-relation of estimation vs. measurement—linear regression: R2 = 0.9986) and integrates the fertigation decision support system—DSS-FS fertigation simulator. This provides a more effective and reliable method of estimating the EC which will, ultimately, impact management decisions.