In:
Frontiers in Plant Science, Frontiers Media SA, Vol. 12 ( 2022-1-12)
Abstract:
Nitrate nitrogen ( NO 3 - -N) in the soil is one of the important nutrients for growing crops. During the period of precipitation or irrigation, an excessive NO 3 - -N readily causes its leaching or runoff from the soil surface to rivers due to inaccurate fertilization and water management, leading to non-point source pollution. In general, the measurement of the NO 3 - -N relies upon the laboratory-based absorbance, which is often time-consuming, therefore not suitable for the rapid measurements in the field directly. Ion-selective electrodes (ISEs) support the possibility of NO 3 - -N measurement by measuring the nitrate ( NO 3 - ) ions in soil quickly and accurately due to the high water solubility and mobility of NO 3 - ions. However, such a method suffers from a complicated calibration to remove the influences caused by both temperature and other ions in the measured solution, thus limiting field use. In this study, a kind of all-solid ISE system combined with a temperature sensor and a pH electrode is proposed to automatically measure the concentrations of the NO 3 - -N. In this study, a soil water content calibration function was established, which significantly reduces a relative error (RE) by 13.09%. The experimental results showed that the stabilization time of this electrode system was less than 15 s with a slope of −51.63 mV/decade in the linear range of 10 –5 –10 –2.2 mol/L. Both the limit of detection of 0.5 ppm of the NO 3 - -N and a relative SD of less than 3% were obtained together with the recovery rate of 90–110%. Compared with the UV-Vis spectroscopy method, a correlation coefficient ( R 2 ) of 0.9952 was obtained. The performances of this all-solid ISE system are satisfied for measuring the NO 3 - -N in the field.
Type of Medium:
Online Resource
ISSN:
1664-462X
DOI:
10.3389/fpls.2021.810214
DOI:
10.3389/fpls.2021.810214.s001
DOI:
10.3389/fpls.2021.810214.s002
Language:
Unknown
Publisher:
Frontiers Media SA
Publication Date:
2022
detail.hit.zdb_id:
2687947-5
detail.hit.zdb_id:
2613694-6
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