First, an overview
In order to improve the drought management level of agricultural and animal husbandry, grasp the land drought dynamics, to avoid or reduce the losses caused by the drought, and gradually establish a soil moisture monitoring system wide coverage has become one of the important task of corresponding management departments.
Soil moisture monitoring system can realize continuous monitoring of soil moisture (soil moisture) for a long time. The user can flexibly arrange the soil moisture sensor according to the monitoring needs, and the sensor can be arranged at different depths to measure the soil moisture content of the section. The system also provides additional expansion, can increase the corresponding sensor according to the monitoring and monitoring of soil temperature, soil conductivity, soil pH, groundwater level, water quality, air temperature, air humidity, light intensity, wind speed, rainfall and other information, so as to meet the need of system function upgrade.
The soil moisture monitoring system can comprehensively and scientifically and objectively reflect the changes of soil in the monitoring area, can timely and accurately provide the soil moisture status of each monitoring point, providing important information for drought mitigation.

Two, solutions
1. System constitution
Soil moisture monitoring system is mainly composed of four parts: monitoring center, communication network, remote monitoring equipment and soil moisture content detection equipment.
The monitoring center
Hardware mainly consists of server, computer, switch, printer and so on.
The software mainly consists of operating system software, database software and soil moisture monitoring system software.
The communication platform
Including China Mobile GPRS network and INTERNET public network.
The system plan adopts the network mode of public network, and the monitoring center should have the fixed IP address which can be connected to the network.
The remote monitoring equipment
The remote monitoring equipment according to the power supply types of electric power supply, solar power supply terminal of soil moisture monitoring soil moisture monitoring terminal and battery powered soil moisture monitoring terminal.
In view of the scattered distribution of soil moisture monitoring points and difficult to wiring, it is recommended to select the solar powered soil moisture monitoring terminal.
The soil moisture detection device
According to the monitoring requirements, can use 1 soil moisture sensor to achieve a single point moisture detection; also can use multiple soil moisture sensor, and the sensor is arranged in different depth profile of soil moisture monitoring points.
2, system function and characteristic
Soil moisture monitoring system can be monitored continuously throughout the day. Automatic acquisition of real-time data of soil moisture remote monitoring equipment on the site, and the use of GPRS wireless network to realize remote data transmission; automatic monitoring center monitoring data receiving, automatic storage of each monitoring point to the database. The main functions of the system are as follows:
Complying with the latest soil moisture monitoring standard SL 364-2006.
To monitor soil moisture in real time, each monitoring point can be flexibly measured by single channel or multi channel profile.
When the soil moisture exceeds the preset limit value, report the alarm information immediately.
The monitoring function of soil temperature, conductivity, pH value, groundwater parameters and meteorological parameters can be extended.
The data acquisition and storage frequency can be flexibly adjusted, and the working parameters of the monitoring equipment can be set remotely.
The remote monitoring equipment to the sensor supply only in the acquisition of data, on the one hand, saving energy, on the other hand to avoid the measurement error due to the long-term power supply caused by the formation changes of soil physical properties.
Support GPRS, short message, LAN and other communication methods, recommend the use of GPRS wireless communication.
It is possible to report monitoring data to multiple centers simultaneously.
With remote equipment maintenance function, it can extend remote camera function.
It has the function of statistics and analysis of monitoring data and alarm data, and the data report can be exported and printed out.
The monitoring system software has the function of GIS, which can display the detailed distribution position of each monitoring point on the map.
Monitoring system software supports interfacing with other systems through OPC interface.
3 、 main hardware equipment of the system
(1) soil moisture monitoring terminal
The installation: vertical rod installation or wall installation.
The way of power supply: solar power.
Turning to the sensor supply voltage: 10~30V.
The communication with the monitoring center: GPRS.
The data report: real time reporting.
The core product: core product monitoring terminal within the selection of YD-1003 type low power control terminal. The product integrates data acquisition, display, transmission and storage functions, the design of low power consumption, the field monitoring is especially suitable for solar power, can greatly reduce the cost of solar power and reduce the difficulty of construction.
(2) product characteristics
Data acquisition and transmission integrated design.
GPRS real-time online low power consumption, the average current is less than or equal to 10mA.
Optional data transmission protocols, such as hydrology and water resources, etc..
Support users to develop their own software system.
(3) technical parameters
Hardware configuration: 6 way PI, 4 way DI, 4 way AI, 3 way DO, 2 way serial port.
Memory capacity: 4M.
Power supply: 10V ~ 30V DC.
Power consumption: standby current less than 0.1mA/12V;
Line current is less than or equal to 6mA/12V;
Send the current less than or equal to 60mA/12V;
Real time online average current: less than 10mA/12V.
Working environment: temperature: -40 ~ +85 humidity: less than or equal to 95% DEG C.
Installation method: Rail type.
(4) soil moisture sensor
Moisture is the main factor to determine the soil dielectric constant. Measuring the dielectric constant of soil can directly and stably reflect the real moisture content of various soils. The percentage of soil moisture sensor can measure soil water volume, has nothing to do with the mechanism of soil, soil moisture measurement method is currently the most popular. Soil moisture sensor is a high precision, high sensitivity measurement