1. Soil Moisture Monitoring Using Wireless Sensor Network
Ruixiu Sui
USDA-ARS
Crop Production Systems Research Unit
Stoneville, Mississippi
18th World Congress of CIGR
Beijing, China
September 16-19, 2014

2. INTRODUCTION Mid-South of USA Major crop production Area
Annual Precipitation: 130cm
Hot and Less rainfall in summer
Supplemental irrigation needed
Irrigated
Irrigated
Non-Irrigated

3. INTRODUCTION
Uncertainty in the amount and timing of rainfall is a serious risk to producers in the Mid-South
Producers have become increasingly reliant on irrigation, but very few use any irrigation scheduling aids
Timely and accurate determination of soil water status and weather conditions are essential to irrigation scheduling

4. INTRODUCTION
Mid-South
Region

5. INTRODUCTION Irrigation scheduling methods
Weather-based -- schedule irrigation based on the amount of water lost by plant ET and the amount of effective rainfall and irrigation water entering into the plant root zone.
Soil moisture-based -- measure soil moisture levels in the plant root zone and apply water if there is water shortage for plants
Plant-based -- directly detect plant responses to water stress and initialize irrigation as plants indicate suffering from water stress.

6. INTRODUCTION
Soil moisture measurement required for soil-moisture-based irrigation scheduling
Sensor technologies available for measuring soil moisture -- neutron probes, electromagnetic (EM) sensors (capacitance, TDR, resistance,..)
Wireless sensor networks offer capability of providing continuous, real-time, in-situ measurements under a variety of operating conditions

7. OBJECTIVES
The goal of this research is to develop improved irrigation application and scheduling techniques for humid regions
Specific objective is to develop wireless sensor network (WSN) for monitoring soil water status and collecting weather data for irrigation applications

8. Wireless Sensor Network Data Logger & Wireless modem6”
12”
24”
Point
Area
Data Logger & Wireless modem
Access
Data online

9. Wireless Sensor Network
Em50R
Em50G
EC-5
5TM
Data Station
Data logger
Wireless Modem
Wireless Data Logger
Frequency: MHz
Input: 5 Channels
Storage: M
Power: AA Bat.
Data Station receives and stores data from Em50R loggers; Em50G cellular data logger; Modem transmits data online via cellular network

10. Weather Sensors Rain gauge sensor Radiation sensor Temperature sensor
Humidity sensor
Wind speed & direction sensors
Data logger
Solar panel for power supply
10-ft Tower
Software package

11. Sensor Installation
Installed sensors and loggers in multiple locations in cotton, corn, soybean fields
3-4 sensors each location in 15, 30, 46 cm depths
Sensor models: EC-5, 5TM, MPS-2
Soil moisture measured 24/7 at one hour interval

12. Sensor Installation Dig a hole Insert the sensors Horizontally
Soil sampler
Gas-powered auger
2. Put in bracket
Dig a hole
Insert the sensors Horizontally
3 MC sensors/hole
Data Station

13. Issue for Field Operation
Required to lay down the logger pole for applying Chemicals

14. Antenna Mounts Developed

15. Antenna Mounts Test
Click on picture to play video

16. Data Logger Installation
EM50R Logger
2. Put in bracket
EM50G Logger
Data Station

18. WSN in Soybean Field

19. Received Signal Strength Indication (RSSI)
Cotton Field
(Logger 18-50G)
Corn Field
(Logger19-50G)
Soybean Field
(Logger 20-50G)
Date
RSSI
Attempts
14-May-12 19 1 14 NA
21-May-12 10
28-May-12 11
4-Jun-12 20 9
11-Jun-12 2
18-Jun-12 18
25-Jun-12 17 13
2-Jul-12 12
9-Jul-12
16-Jul-12 8
23-Jul-12
30-Jul-12
6-Aug-12
13-Aug-12 15
20-Aug-12 16
27-Aug-12
3-Sep-12
10-Sep-12

20. RSSI in 2013 Logger Location Crop 5/1/13 – 5/15/13 5/16/13 - 5/31/13
6/1/13 - 6/15/13
6/15/13 - 6/30/13
7/1/13 - 7/11/13 1
Cotton
NA* 8 12 11 20 2 NA 17 19 18 3 4 5 6 16 15 7
Corn 77 72 57 55 52 71 64 40 54 9 70 62 33 25 10 66 59 29 30 43
Soybean 76 13 63 61 14 67 60 56 50

21. Downloading Data Online

22. Soil Moisture Data From WSN

23. Soil Moisture Data From WSN

24. WSN collected data for 3 years
Data have been used for irrigation scheduling
Performed well in general
Thunderstorms could interrupt data transmission
Animals (wild dog, pig, turtles) might chew cables
Irrigation Research in Cotton
Variable Rate Irrigation in Soybeans
Corn Research Field

25. SUMMARY
Wireless sensor network was built and deployed for monitoring soil moisture and collecting weather data for 3 years. The WSN is capable of automatically measuring and wirelessly transferring soil moisture and weather data online, enabling remote access of the data;
An antenna mount was developed for field use with wireless data loggers;
Evaluated for 3 years; The WSN performed well;
Soil moisture data and weather data collected by the WSN has been used for irrigation research.

26. Acknowledgements Disclaimer
This project was partially supported by Cotton Inc.
Thank Mr. Jonnie Baggard for his assistance in this project.
Disclaimer
Mention of a commercial product is solely for the purpose of providing specific information and should not be construed as a product endorsement by the authors or the institutions with which the authors are affiliated.

27. THANK YOU Ruixiu Sui, Ph.D.
Research Agricultural Engineer, Lead Scientist
United States Department of Agriculture (USDA)
Agricultural Research Service (ARS)
Crop Production Systems Research Unit
141 Experiment Station Road
Stoneville, MS 38776