Salinizacion

2010 International Conference on Measuring Technology and Mechatronics Automation

Developing Design for Soil Salinization Sensor Based on Electromagnetic and ETMtechnology
Chi Tao, Liu Huifang, Chen Ming Shanghai Ocean University, Shanghai, 201306, China tchi@shou.edu.cn
Abstract—Electromagnetic and ETM-technology -based sensor can provide important information in a number of applicationsincluding environmental monitoring, health care and emergency response. This article describes its architecture, including its design, implementation, and performance. We describe two sensor platforms that can combine the method of electromagnetic properties and the method of spectra properties. In addition, we establish a testing system that can measure the soil salinization. Finally, we describethe reflection characteristics of visible, infrared and microwave in soil, which can be gotten by combining the spectrogram with the TM data. Keywords- Sensor Array; Intelligent Sensor; Sensor Preprocessing; Eelectromagnetic; ETM-technology; Multi-Channel Signal Processing

From the literatures at home and abroad, soil salinity can be on behalf the soil conductivity. Many elements of the soilhave a diagnostic absorption feature in the solar spectral range (0.3-2.5μm). The researchers have done much research on the relation between the soil properties and laboratory spectral reflectance, and successfully predicted the soil composition by using the technology of reflectance spectroscopy. II. SENSOR TECHNOLOGIES Multi-sensor array can be divided into two parts, one part of sensors device isused to detect the soil conductivity, the other is used to monitor the spectral image. A. The sensors device detecting the soil conductivity The sensors device detecting the soil conductivity consists of transmitter and receiver. The transmitter is a small transmitting coil, which can produce a dynamic primary magnetic field according to change of the soil depth along with time. This magneticfield can then produce a little weak AC induction current in the earth, which induces the secondary magnetic field. Then the receiving coil of the receiver receives the secondary electromagnetic signal produced by the soil conduction current. The received electrical signal, which is proportional to the soil conductivity, can appear as the soil conductivity after computing and processing. The ratio ofthe primary and secondary magnetic field is usually in a linear relationship with the soil conductivity. The detected signals are rather weak, so it is necessary to magnify these weak signal, the collected signals have much noise resulting from the magnification. Owing to the noise, the special signal processing circuit is specially designed to magnify signals and decrease noise. The degree towhich the magnetic sensor will absorb a certain wavelength is calculated using Beer-Lambert’s law: I (v ) = I 0 ⋅ e − α ( v ) L (1) where I is the intensity of light passing through the absorbing medium, I 0 is the input intensity, L is the optical path-length through the sample (cm), v is the radiation −1 frequency in wave-numbers ( cm ), and α (v ) is the absorption coefficient of specific targetspecies: α (v ) = C ⋅ S ⋅ g (v − v 0 ) (2) where C is number of molecules of absorbing NaCl/KCl −3 per unit volume ( cm ), S is the molecular line intensity
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INTRODUCTION

The soil salinization is a worldwide problem, while the research on dynamic aspect of the soil salinization mainly focuses on the monitoring, assessment and forecasting techniques. The traditional method of soilsalinization monitoring is the laboratory assay by extracting the soluble salt from the waterlogged soil. This method has many disadvantages, such as complex operating procedure, poor real-time and high detection cost. Some achievement of the research on soil salinization information has been got at home and abroad. At present, the information extraction of soil salinization is mainly based on...