Soil moisture measurement

Now you can gain control of soil moisture and adjust irrigation according to the need. A properly utilized irrigation system provides conditions for optimal growing economy. Excessive irrigation means waste of your time and energy, and you risk plant nutrient leaching. The standard equipment consists of the base unit and a soil moisture sensor. Measurements takes place every hour and uploads to the Internet via GSM network. They can then be viewed via a computer or smart phone.

Each base unit can be provided with three humidity sensors, which is buried in the soil at different depths, independently of each other. You can then monitor how moisture is distributed in the root zone after irrigation. When the sensor dries, it also means that the plant gets more difficult to absorb water. With rain gauge, you get a complete picture of the total precipitation.

Sensors come from by Irrometer, a well-known manufacturer of irrigation equipment. It consists of a perforated steel cylinder of 10×3 cm. Inside there is a plaster block with two electrodes in. When soil moisture varies, the resistance is changed. The value converts to a pressure measured in pascals. Optimally, it should be between 10 and 40 kPa, low values are better. The variation also depends on the crop and soil properties.

You can order via phone +46 46-288 45 20 or email. You are most welcome to call or ask questions. Watch pictures of the equipment in our brochure and fact sheet written in Swedish (pdf).

Base unit with soil moisture unit and rain gauge.

Base unit with soil moisture
unit and rain gauge.

The sensors are buried as soon as possible after planting/seeding, so the crop may form their roots around the sensor. Recommendation is to put three of them, at 15, 25 and 40 cm depths. As the plant grows, the depth that the plant can absorb water increases. With multiple sensors you can throughout the growing season check if there is water available where the roots are. At the beginning of growth moisture is needed in the upper part, when the roots are not so well developed. Later, perhaps a dry surface may not affect so much, since the plant’s roots reach further down. For plants with shallow roots, you don’t need to irrigate, so it shows on the bottom sensors.

In order to utilize the base unit optimally, you can also use it to measure the temperature of clamps and similar storages during autumn and winter. Read more about temperature measurement.

Part Price euro
Base unit with solar cell and battery 700
Soil moisture sensor Watermark 50
Rain gauge 180
Temperature sensor, 2 m cable, air/ground/water 50
Air humidity sensor, incl temperature sensor, mounted in base unit 60

Price
Base unit, cable, one soil moisture sensor, 6 month subscription: 850 euro
Base unit, cable, two soil moisture sensors, 6 month subscription: 900 euro
All prices are excluding VAT.

Deliverance
The equipment is sent as package against fee, or can be picked up in Lund, Sweden.

Deployment
Charge the batteries with the supplied USB cable in the base unit socket. Then you either dig down moisture sensors in the ground, or connect it at home and test the function. Either way, press the button on the bottom of the base unit. The display shows the current moisture levels at all connected sensors, battery status, and any temperature sensors. The measurement is also sent to the internet.

Measurement interval
By default measurements are reported once a day. If you wish to increase the frequency it can be changed. An example would be during the irrigation season you want hourly measurement, and during the winter months to measure the temperature every two hours. In a few weeks during spring/fall to monitor the risk of frost, you want half-hour measurement.

Ambient
The equipment is designed to withstand -20°C and winter weather. During March-September the equipment is driven with battery charged by solar cell. During the winter season, the batteries gives about two to four months of operating time, before you have to recharge them. Read more about batteries for temperature measurement.

Monthly cost
Subscriptions for data charges according to how often you want to measure. Default is once per day. If you wish to increase the frequency you prepay a sum which is then deducted by the frequency measurement is made. Hourly readings of three soil moisture sensors, rain gauge and temperature sensor cost about 12 euro/month.
The base unit will choose an operator that is available, which means high reliability, and that it will work in any country, most likely.

Internet service
Your measurements are shown on a website when you log on. You can name the sensors and the base unit. All measurement data can be exported to an Excel file for detailed analyzes. See our video tutorial on how to export sensors and create charts.
You can also set alarm levels for the various sensors that are connected. This will send an email and/or sms when the value are above or below your setting.
Examples of the presentations of measurements can be seen at our demonstration web.

References
During the season 2013 we participated in a field trial which the Swedish Rural Economy and Agricultural Societies (HS) did to evaluate different systems for optimization of irrigation.
Since the season 2011-12 Nordic Sugar Agricenter Sweden uses our equipment in sugar beet clamps for storage trials in collaboration with Nordic Beet Research.

Theft Protection
The base unit can be locked in the GSM operators theft records and then becomes useless to a thief. It can also be tracked geographically.