In continuation of the ICAR-SBI Soil Moisture Indicator (SMI) one of the licensee M/s SKR Agrotech, Nagpur, has developed an improvised the SMI named the device as Digital Soil Moisture Sensor (DSMS). SMI technology is simple and soil moisture displayed as colour light indication but recent times, there is a demand from certain farmers for an SMI with digital display with or without digital communication to android mobile like using GSM. ICAR-SBI has tested and validated the SKR Agrotech version of SMI in a PPP project by using different types of soils under controlled laboratory condition. A comparison of DSMS moisture values and actual soil moisture values was made for different soil types and it was seen that there is a very high correlation between DSMS moisture values and actual moisture values estimated in the lab. It was found this DSMS would be preferable for farmers who desire to have digital display and android compatibility.

Technical Description

Model No.1- DSMS (Economic)

            DSMS comprises microcontroller based sensor rod and a casing. There are either two metal sensor rods (two individual rods spaced at distance of about 5 cm) or a combined rod.  The casing houses an electronic printed circuit board with an integrated circuit, electronic components, a provision for lithium battery and a control switch. To assess the soil moisture, the stainless-steel sensor rods are to be inserted into the soil. The resistance between the sensor rods depends on the moisture content in the soil between the rods. Lower the soil moisture higher will be the resistance and vice versa. When a direct current voltage is applied between the sensor rods, there will be a voltage change in relation to the soil moisture. This altered voltage is fed to the signal input of the integrated circuit. The integrated electronic circuits translate conductivity into soil moisture content through OLED display and displays quantitative moisture percentage. The electronic circuit is designed in such a way to display moisture levels digitally. The moisture level indication will be as quantitative analysis of water holding capacity in 0 to 100 % range. A provision is given in the electronic circuit for fine-tuning the device to suit different soil conditions like sandy, clay and loamy.

Technical description of Model No.2- DSMS (with GSM Module)

Similar to Model 1 but has additional feature with GSM module.