One shot evaluation of NPK in soils by “electronic tongue”

Smart introduction of fertilizers in the soil should help to decrease the negative impact of chemicals on the environment without dramatic reduction of crop yield. The amounts of fertilizers have to be carefully tuned according to actual nutrients content in the soil and vegetation period of the plants. Since most of the chemical soil analyses are performed in the laboratory nowadays, fast and simple analytical tools have to be developed for this task. In this study, a potentiometric multisensor system was used for simultaneous determination of the N, P and K in the water extracts of the soils. It was shown that potentimetric sensors with multivariate data processing can be used for assessment of all three macronutrients, along with estimation of pH and conductivity of soil samples. Correlation coefficients between targeted parameters and sensor responses varied from 0.69 to 0.96. The quantification of N was possible with RMSE of 50 mg/kg in the range 60–426 mg/kg. The main benefits of the proposed approach are the short measurement duration – just 8 min for all the parameters, and reagentless procedure.