Development of a Portable Multiple Ion-Selective
Electrodes Apparatus for Rapid Soil Nitrate Measurement
Eko Leksono* and V.I. Adamchuk
Department of Bioresource Engineering McGill University, Canada
Nitrate is crucial for plant growth and development. The availability of soil nitrate should be balanced to avoid various agronomical, environmental and health problems. One way to solve those problems is by applying variable rate fertilizer application (VRA). Currently, there are vehicle mounted platforms that can perform on-the-go soil chemical measurements. However, those platforms were not suitable for farmers with small and scattered fields. Therefore, our research objective was to design a portable soil nitrate measurement apparatus. The apparatus uses multiple Ion-Selective Electrodes (ISEs) and follows the direct soil measurement (DSM) method. A four channel Tentacle-Arduino shield data acquisition system (DAQ) was used for acquiring ISE data. Furthermore, additional functionality, such as georeferencing, instrument nulling, data logging and power checking were added to the DAQ system. The DAQ did not have crosstalk error among the channels. However, noises were observed but not caused by the Tentacle itself rather it came from the PC power line and the ISE condition. For further development, the apparatus should be modified with a larger droplet and a low spray angle sprayer to provide better ISE cleaning. Procedure for DSM should also include a routine calibration and ISE submersion into deionized water to reduce sensor drift and hysteresis.
Keywords: Direct Soil Measurement, Ion-Selective-Electrode, Nitrate, pH, Variable Rate Application
Full Text PDF of D14 Leksono et al