An algorithm based on electrical conductivity for accurate liquid nitrogenous fertiliser application

Abstract

For basal and foliar treatments, precise administration of nitrogenous fertilizers—primarily urea ammonium nitrate (UAN) and
granular urea, both pure and neem-coated—in aqueous form is crucial. When designing a liquid fertiliser administration
system, the physicochemical characteristics of these nitrogenous fertilisers' aqueous solution are crucial. In order to create
algorithms for use in sensor-based systems for real-time monitoring of the available N content in the fertiliser solution before
to application, the research was conducted in 2019–20 at the ICAR-Indian Agricultural Research Institute, New Delhi. The
physicochemical characteristics of urea ammonium nitrate (UAN-28%), pure urea, and neem coated urea in diluted form (pre-
selected N-concentrations i.e. 0.78, 0.9, 1.08, 1.33, 1.75, 2.54, and 4.67% corresponding to the dilution ratios of 1:35, 1:30,
1:25, 1:15, 1:10, and 1:05) were measured and their significance with N-concentration. N-concentrations were significantly
correlated with electrical conductivity (EC) alone. Based on the EC and N-concentrations, prediction models were created for
granular urea fertilisers and diluted UAN. With coefficients of determination (R2) of 0.998, 0.998, and 0.999 for diluted UAN,
pure urea, and neem coated urea with water, respectively, the regression models in terms of EC to predict N-concentration
shown a remarkable promise for their sensor-based precision application. Sensing pertinent physicochemical properties allows
for the regulated administration of diluted liquid fertilisers with water.