Temperature compensation type high-precision calibration method for soil salinity sensor

Abstract

The invention relates to a temperature compensation type high-precision calibration method for a soil salinity sensor, and belongs to the technical field of soil salinity sensor calibration. The technical problem of how to provide the temperature compensation type high-precision calibration method for the soil salinity sensor is solved. The method comprises the following steps: 1, determining a calibration saline solution according to the main salt composition of soil in a use area; 2, preparing a highest salt solution, and preparing a gradient standard salt solution according to a dilution method; 3, putting the gradient standard saline solution into water with different temperatures, and preparing saline solutions with different temperatures; and 4, sequentially putting the soil salinitysensors into the saline solution at different temperatures, recording output signal values of the standard salt solubility of the soil salinity sensors, and obtaining a temperature compensation formula and a salinity sensor absolute calibration formula according to the acquired signal values. The method is suitable for calibration of multiple types of soil salinity sensors, and the calibration result is more accurate and reliable due to the adoption of a fine temperature compensation function.

Description

Technical field [0001] The invention belongs to the technical field of measurement, and relates to a calibration method of a salinity sensor, in particular to a temperature compensation high-precision calibration method of a soil salinity sensor. Background technique [0002] Soil salinity sensors are more and more used in scientific research to monitor soil salinity. It has the advantages of rapid, accurate, multi-point continuous determination, and can automatically and remotely measure changes in soil salinity. So far, domestic and foreign experimenters and engineering technicians have proposed more than a dozen soil salinity sensors based on different principles. The measurement methods include gravimetric method, conductivity method, hydrometer method, and total anion and cation calculation method. However, various soil salinity sensors have different measurement accuracy and spatial sensing ranges. In order to ensure the measurement accuracy of each soil salinity sensor, it...

AI Technical Summary

Problems solved by technology

Therefore, several solutions are generally prepared, so that the number of measurement points is small, the calibration accuracy is not high, and there is no consideration of the temperature compensation coefficient or a simple fixed temperature compensation coefficient, the error is large, resulting in inaccurate final calibration results.

For example, the "soil salinity sensor (application number: CN200420078419.0)" invented by the Nanjing Soil Research Institute of the Chinese Academy of Sciences (2004) uses a calibration method to calibrate eight kinds of salt solutions, with few sampling data points, insufficient measurement points, and small coverage At the same time, the conductivity value of the salt solution changes with the temperature, and the temperature change is corrected by using a fixed value of about 2% change in the conductivity value of the solution every degree of temperature change. The actual temperature-salt relationship coefficient value is a variable, and it will decrease as the temperature rises. Such a calibration value has a large error and the calibration result is inaccurate

Images