Soil moisture and precipitation monitoring

Introduction
Soil compaction is becoming an increasingly severe problem, not only in agriculture, but also in rural construction sites. While tractors and harvesters will hopefully never reach US dimensions, due to limited field size, heavy construction machinery, trucks and caterpillars are moving all around construction sites with little regard to the compaction of soil and its dire consequences. Since soil moisture is a fairly good indicator of a soil's susceptibility to compaction, the government of several Swiss provinces (called "Kanton" in the local language) decided in the late '80ies and early '90ies to install a network of manual monitoring stations, equipped with tensiometers and rain gauges, to provide guidance and regulation to the operators of machinery.

The Challenge
Since the network was getting larger and manpower increasingly more expensive and scarce, several Swiss provinces decided to replace their manual sites with automatic sites, collecting and transmitting daily hourly rather than two or three times per week. In addition to soil tension precipitation and, at several locations, additional meteorological parameters needed to be monitored and transmitted back to base. At HQ this data needed to be placed automatically on a map accessible through the website of the provinces (www.bodenmessnetz.ch) and showing through an easily understandable colour system (red - yellow - green), if conditions were suitable for operating heavy equipment or not.

The Solution
The first province to automate selected an ADCON telemetry system for the task. With pretty much all of Switzerland being covered well by mobile phone networks, GPRS was the transmission technology of choice. To get the best possible soil tension readings, a science-grade tensiometer was selected, the UMS T8, which was customized for Adcon to work with SDI-12 and low power. To overcome the imminent time-lag of this measurement technology between precipitation and soil moisture actually going up, professional rain gauges, Adcon RG Pro‘s, were installed at each site. At most sites the entire system is powered by a dual-setup of Adcon solar panels. Some sites required mains power, as heated rain gauges needed to be installed.

Summary
With the first 3 stations being a convincing demonstrator, the network has by now grown to over 30 sites. Adcon distribution partner Meteotest in Bern performs highly professional installations and permanently monitors the performance and integrity of the network in order to take action on time in case of any trouble. Meteotest also makes sure that data is properly exported to the customers' website, that all software is kept up to date and that periodic backups are being performed. The system is functioning flawlessly and will continue to be expanded.

ADCON Products deployed in this project:

• A850 Telemetry Gateway
• A753 addWAVE GPRS
• 540mA Solar Panel
• Adcon RG Pro
• T8 Tensiometer
• Adcon TR-1