New Zealand Journal of Agricultural Research abstracts

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Development and modelling of a soil nitrate and potassium simultaneous rapid detection system based on ion selective electrodes

Lin Jianhan

Wang Maohua^*

Zhang Miao

Zhang Yane

Key Laboratory on Modern Precision Agriculture System Integration Research
China Agricultural University
Mailing Box 125
No. 17 Tsinghua East Road
Beijing, PR China

^*Author for correspondence: wangmh@cau.edu.cn

Abstract    Conventional soil nitrate and potassium detection methods are reliable, but time-consuming and expensive. Rapid lower-cost detection methods for soil nitrate and potassium are urgently needed. In this study, a temperature-calibrated soil nitrate and potassium rapid simultaneous detection system was developed based on two ion-selective electrodes (ISEs). At room temperature, the potentiometric experiments were conducted to evaluate the performance of both ISEs and simple linear regression (SLR) was used for modelling. The lower detection limits of both ISEs were 1 × 10^–5 mol/litre with regression coefficients of 0.994 and 0.997, respectively. Under different temperatures, the potentiometric experiments were conducted and multiple SLRs were used for temperature-calibrated modelling with a maximum relative error of c. 6% and c. 10%, respectively. An ISE signal acquisition system was developed based on a microprocessor, including an ISE signal conditioning unit and a temperature measurement unit using a thermal resistor. This study might be suitable for in-field soil nitrate and potassium rapid detection application.

Keywords    ion selective electrode; nitrate; potassium; soil nutrient ion concentration rapid detection; soil testing

A07072; Online publication date 17 December 2007 Received and accepted 10 August 2007

New Zealand Journal of Agricultural Research, 2007, Vol. 50: 635–640
0028–8233/07/5005–0635 © The Royal Society of New Zealand 2007

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