1. Overview
The plug-in soil moisture observation system uses sensor plug-in contact measurement to obtain soil indicators. Generally, plug-in soil moisture observation belongs toTDR (Time Domain Reflectance) and FDR (Frequency Domain Reflectance) methods.
The plug-in soil moisture observation system uses sensor plug-in contact measurement to obtain soil indicators. Generally, plug-in soil moisture observation belongs toTDR (Time Domain Reflectance) and FDR (Frequency Domain Reflectance) methods.
Firstly, let's understand several quantities of soil moisture:
The forms of water in soil are solid water and gaseous water
Field water holding capacityIt refers to the soil moisture content when a large amount of capillary water is suspended in the soil without being affected by groundwater.
soil moisture contentGenerally refers to the excellent soil moisture content, i.e100gDried soil contains several grams of moisture, also known as soil moisture content.
These indicators are closely related to the type of soil, and the general types of soil are as follows:Typical soil moisture content:
Soil type |
Saturated state |
General water capacity |
Long term adjustment point |
Plants can use water |
Fine sand soil |
15-20 % |
3-6 % |
1-3 % |
2-3 % |
Sandy loam soil |
20-40 % |
6-14 % |
3-8 % |
3-6 % |
Silt loam soil |
30-50 % |
12-18 % |
6-10 % |
6-8 % |
Sticky loam soil |
40-60 % |
15-30 % |
7-16 % |
8-14 % |
clay |
40-70 % |
25-45 % |
12-20 % |
13-20 % |
The movement and storage of soil water:
2. Measurement method for soil moisture content:
TDR(Time domain reflection method
TDRIt is based on the different transmission times of electromagnetic waves emitted by the detector in materials with different dielectric constants,And calculate the moisture content of the tested substance. The propagation speed of electromagnetic waves is closely related to the dielectric constant of the propagation medium,However, there are significant differences in the dielectric constants of soil matrix, water, and air(20At ℃,The dielectric constant of water is80,The dielectric constant of air is1,The dielectric constant of dry soil is between3~7)Therefore, changes in soil moisture content have a significant impact on the dielectric constant,Thus, the propagation speed of electromagnetic waves,You can determine its moisture content.
FDR(Frequency domain reflection method
FDRSoil moisture monitoring instrument is a type of instrument that utilizesLCThe oscillation of a circuit is determined by measuring the dielectric constant of a medium based on the changes in the oscillation frequency of electromagnetic waves in different mediaε, and then deduce soil moisture through a certain corresponding relationshipθvThe instrument.
3. Application of Soil Moisture Station:
•Important guarantee for data quality control and rationality inspection
•Realize unified data management
•Convenient for users at all levels to use and manage
•No need for a fixed computerNo need to install special software
•Save on-site collectionHuman and material resources for data management
Working principle diagram:
•Building a basic data platform at the bottom level
•stayBuilding an application system based on the WebGIS (Sky Map) platform
•Divide the application system into front-end and back-end, front-end (homepage)+The central station page+local station page is used for application display, and the backend is used for maintenance and management
•supportBrowse online on PC or mobile (Android Baidu Browser, Mobile UC Browser) anywhere with internet access
Soil moisture station management platform:
Wireless transmission function:
Interface display
The login interface includes options such as homepage, data, warning, announcement, management, and help. You can directly query the data information of a certain time, a certain site, or a sample site.
get intoThe "Data" option, with the site on the left side of the interface. Drop down options for sample plots, with time options on the right, allowing for detailed observation of data lists, line charts, statistical data, and other information for a certain site sample plot at a certain time, and exporting. csv files for the selected time and sample plot.
Data line chart:
Data List:
Soil moisture observation system Data management platform
Data transmission and management
Interface display:
get intoThe "Warning" interface allows for a clear view of stations and sites with abnormal communication.
The "Management" interface has options for "User Management", "Threshold Management", "Monitoring Station Information", "Historical Data", "Announcement Management", and "Data Reporting Management" on the left side of the homepage. On the right side of the homepage are all "System Administrators" and "Station User Information"
stayThe "Monitoring Station Information" interface allows system administrators to modify and view site and plot information.
stayIn the "Announcement Management" interface, system administrators can add announcements and view announcement information
Data information can be reported in batches by year and time period. System administrators can view and delete reported data informationWaiting for management.
4. References:
1.Dynamic analysis of soil moisture growth season in semi-arid loess hilly area-Xu ZhiyaoZhang Qindi, Yang Lei
2.Study on the Water Transport Law of Different Soil Types-Wang Suyu
3.Optimization deployment method for soil moisture monitoring based on effective high moisture content-Wang Shan,Hu Zhenhua
4.Research progress on temporal stability of soil moisture-Lin PengfeiZhu Xi, He Zhibin
5.The fluctuation of soil moisture on alpine grassland ecosystemThe impact of CO2 and N2O emissions-Wang Rui,Wang Ping, Gao Yongheng