Study On The Method Of Real-time Detection Of Soil Salinity

Soil salinity is the main parameter to characterize soil condition and is the most important index to determine the degree of soil salinization.In the development of tine agroforestry,it is of great significance to study the method of real-time detection of soil salinity.Existing soil salinity testing instruments are mostly based on the soil electrical conductivity detection method,not considering the soil moisture content,temperature and density on the influence of the conductivity of soil.It not only results in a large measurement error,but also has a high requirement for the measurement environment.In order to improve the accuracy and maneuverability of soil salinity in real-time detection.the paper made the following research:1.The paper starting from the research principle of soil salinity in real-time detection,completed the function design of the detection device,set up the hardware detection system based on STM32 and software design based on ucosii operating system.The stability and feasibility of the detection system were verified through the performance test(including calibration test,stability test,consistency test,comparison test,etc.).2.On the basis of acquiring soil moisture content,temperature and bulk density,conductivity of soil were obtained in real time.then the influence of soil moisture content,temperature and bulk density on the results of soil conductivity measurement was analyzed,and the electrical conductivity influencing factors experiment was completed.The correction model of soil moisture,temperature and bulk density on conductivity was established.The electrical conductivity under the temperature of 0?30?,the bulk density of 0.8?1.6g/cm3 and the moisture content of 11%?32%was converted to the electrical conductivity under the temperature of 25? and the bulk density of 1g/cm3.3.The experiment proved that the coefficient of the linear fitting of soil conductivity and salt content is 0.9978 when the soil salt content is less than 0.3%.On the basis of the electrical conductivity correction model,the soil salt content detection model was established,which achieved the purpose of on-line real-time detection of soil salt content.4.Soil moisture content was obtained by drying method.Soil electrical conductivity and salt content were obtained by Spectrum FieldScout EC110 and Jenco 3010M.As the true value,it was compared with the self-made detection device.The results showed that the water content,electrical conductivity and salt content by the self-made detection device were more than 0.95 of the linear fitting coefficient of the true values corresponding to each other.The standard deviation of the long time test data in the same environment was 0.003586.indicating that the stability of the soil salt content detection device was good.The correlation between the detection devices was higher than 0.9.and the consistency was good.The relative error between the detection device and the contrast instrument was within 9%,and the precision was equal.To sum up.the method of real-time detection of soil salinity proposed in this paper is feasible.And the soil salinity detection device designed according to this method has good stability and precision.It is able to complete the measurement of soil salinity and provide a practical and reliable sensor for fine agroforestry.