Concentration of potassium as a function of electrical conductivity of soil solution

Abstract

The monitoring of ions in the soil should be done to evaluate the fertigation and should accampamj the application of fertilizers, noting the concentration of the injecting solution and uniformity of distribution. The objective was to evaluate and to validate models for estimating potassium concentration in the soil solution as a function of electrical conductivity (ECw). Treatments consisted of using three solutions of potassium chloride (1.0; 2.5 e 4.0 g L^-1) applied by two trickle irrigation systems (microsprinkler and drip) during the first crop cycle. Data collection of electrical conductivity of the soil solution and evaluation of the concentration of potassium in the soil solution during the cycle of banana crop were performed. The model was evaluated by using field data during one cycle of the banana cv Terra Maranhão. Results showed that it is feasible to estimate the potassium concentrationin in the soil solution from data of ECw by using a potential model. The potassium concentration in the soil solution may be estimated from readings of electrical conductivity under field conditions considering the mean of normalized error of 20 to 25%, model efficiency of 0.55 to 0.68% and root-mean-square error (RMSE) in the range 9.41 to 14.29 mg L^-1.