UUDISED

GOOD PROJECT EXAMPLE: Development of the Prototype for Soil Moisture Sensors

The problem to be solved

In terms of grain production, environment and fertility of the soil, it is important to minimize the loss of nutrients, ensure timely soil tillage and reduction of soil compaction. In Estonia, the conditions are favourable for the leaching of nutrients because the amount of precipitation exceeds evaporation approximately 1.5 times. Soils are often saturated with water in spring and thus, susceptible to compaction. The optimum moisture content of soil during soil tillage contributes to the reduction of soil compaction.

The objective of the innovation activity was to develop a digital sensor prototype for measuring soil electrical conductivity and for the exchange of data to provide dynamical data about the following parameters:

• Salinity level of soil (the content of nutrients)
• Volumetric wetness of soil
• Soil temperature

Knowledge on these parameters will help agricultural producers to carry out fertilisation, soil tillage and sowing in time. 

“It may take months to get the results of soil tests from the laboratory. The reason for the development of the soil sensor is directly related to the wish of farmers to get information about the soil without any delay, to be able to plan fieldwork based on reliable information.” Roosi Soosaar, the project manager

Project outcomes

Sensors keep providing information about moisture, salinity level and temperature of the soil all year round. Data conveniently reaches from the field to the server and to the user´s computer. Sensors are perfectly capable of identifying changes in the temperature of the soil. In order to register data on moisture and salinity of the soil, sensors should get very good contact with the soil solid phase. Therefore, the results largely depend on the installation of the sensors.

The sensors developed in the project can successfully identify relative changes in the moisture of the soil over time; however, the accuracy is not always sufficient for assessing the absolute values and therefore, additional measurements and calibrations of different soils should be carried out. The sensitivity of soil salinity identification is modest, particularly in case of dry soils; additionally, the contact with the soil solid phase is deficient. To act operatively in crop production fields based on the received information, it is necessary to keep on working on the accuracy of the sensors.