Research Of Soil Nitrogen Content Rapid Detection Method And Sensor

Due to the fact that soil nitrogen surplus will directly affect the yield and quality of crops, and nitrogen loss can cause eutrophication of water and greenhouse effect, fast accurate measurement of soil nitrogen content (SNC) is instructional to fertilization and of great significance to precision agriculture.In order to study the real-time detection method of SNC, this article has done the following work:1. First, this article measured the soil nitrogen content with the basement on the spectrum analysis. The correlation of spectral reflectance and SNC is analyzed respectively. Using 4 methods to build the SNC estimation models and testing all of them. Experiment showed that the characteristics band of spectral reflectance for SNC is respectively 425-472 nm,2185-2205 nm, et al. PLSR Models generally have higher accuracy and better stability, and all R2 of the models are higher than 0.958, the highest prediction R2 is 0.841.2. Secondly, this article researched a standing wave ratio SNC sensor which is based on the dielectric theory. The calibration test and sensor performance experiments were done. The sensor calibration model of decision coefficient R2 is 0.960, and the results showed that the sensor measurement is found to be reliable and have good dynamic performance and stability from the result, so it is capable to complete the measurement of SNC.3. Finally, spectroscopy and dielectric measurement were compared. The results showed:the model checking R2 are 0.862 and 0.840, it illustrates the measurement results of the two methods are compliance. The measurement accuracy of spectroscopy is higher, and the measurement process of the SNC sensor is easier.