Sensing Technology of Soil Physical Properties

Abstract

AbstractSoil physical properties mainly refer to various physical phenomena and processes produced in the three-phase system of soil solid, liquid, and gas. It mainly includes the color, texture, density, structure, porosity, moisture, compaction, heat (thermal property), air condition, and cation exchange capacity (CEC) of soil, as well as the mechanical and physical properties and electromagnetic properties of soil. Among these properties, texture, porosity, moisture, compaction, and CEC of soil are very important for crops and need to be quickly and accurately sensed and automatically controlled in precision agriculture. The laser diffraction (LD) method is used as a fast detection method of texture. Dielectric parameters, neutron meter, and near-infrared spectroscopy are used as a main detection method of soil moisture. Frequency domain reflection (FDR), standing wave ratio (SWR), and time domain reflection (TDR) are effective methods based on dielectric parameters. Image processing is used on soil bulk density online detection. Penetrometers and on-the-go measurement are popular in the detection of soil compaction. Visible and near-infrared (vis-NIR) spectroscopy has become the most promising measurement technique to provide accurate and meaningful data on soil CEC for successful decision support on soil fertility management. The determination of soil physical properties provides the basis for soil studying, soil improvement, and soil scientific management. The rapid and accurate measurement of soil physical parameters can promote water-saving irrigation and precise fertilization and improve the yield and quality of crops.KeywordsSoil textureSoil porositySoil moistureSoil compactionSoil CEC