基于FBG的农业大棚土壤温度测量与研究

Measurement and Research of Greenhouse Soil Temperature Based on FBG

研究农业大棚土壤温度,对农业生产具有重要意义。针对传统热电偶等传感器测量土壤温度场存在效率低、误差大等问题,该文采用一种基于光纤布拉格光栅(FBG)的温度传感器来监测农业大棚内的土壤温度变化。该方法将封装了FBG串的不锈钢管垂直埋入被测土壤中,采用可调谐激光器法和寻峰算法解调FBG串各传感器波长,在大棚环境下进行了土壤多层温度场测量实验。实验结果表明,土壤内部温度呈余弦函数模型周期性变化。随着土壤深度增加,温度变化逐渐减小,在一定的湿度范围内,土壤湿度越大,浅层土壤温度越低。土壤湿度对深层土壤温度影响较小,太阳辐射对浅层土壤温度影响较大。

Studying soil temperature in agricultural greenhouses is of great significance for agricultural production.In response to the problems of low efficiency and large error in measuring soil temperature field using traditional sensors such as thermocouples,this paper adopts a temperature sensor based on fiber Bragg grating(FBG)to monitor soil temperature changes in agricultural greenhouses.In this method,the stainless steel tube encapsulated with FBG string is vertically buried in the soil to be measured,and the wavelength of each sensor of the FBG string is demodulated by the tunable laser method and peak seeking algorithm.An experiment was conducted to measure the multi-layer temperature field of soil in a greenhouse environment.The experimental results indicate that the temperature inside the soil varies periodically in a cosine function model.As the soil depth increases,the temperature change gradually decreases.Within a certain humidity range,the higher the soil humidity,the lower the temperature of the shallow soil.The influence of soil moisture on deep soil temperature is relatively small.Solar radiation has a significant impact on the temperature of shallow soil.