The model which I would like to share with all of  you was made by Miss Priyanka Chourasia. This tenth grader presently studies in Guru Govind Singh Khalsa Public High School, India . She had from Ghama , a remote area of Madhya Pradesh, India. Priyanka had shown how soil moisture can prove to be useful for farmers and help them in watering crops. It is nice to see that children from remote areas are also aware of the solutions to many problems. In her model as shown  below the system to indicate soil moisture was shown in which 2 LED lights were fitted the red light glowed when there is no moisture in the soil and the blue light glowed when moisture is present in the soil. Her model is really helpful especially in countries like India, where agriculture is the major source of income. I?ll share with you a few more model in the upcoming reports .

Soil moisture sensor or indicator measure the volumetric water content in soil. Since the direct gravimetric measurement of free soil moisture requires removing, drying, and weighting of a sample, soil moisture indicator  measure the volumetric water content indirectly by using some other property of the soil, such as electrical resistance or  dielectric constant  to measure presence of  moisture content. The relation between the measured property and soil moisture must be calibrated and may vary depending on environmental factors such as soil type, temperature, or electric conductivity.  

In the high level Soil moisture sensors refer to sensors that estimate volumetric water content. There other type of such instrument made of sensors measure another property of moisture in soils called water potential these sensors are usually referred to as soil water potential sensors.

Application :- This type of instrument is used mainly for agriculture for effective utilization of save water .

In Agriculture , the measuring soil moisture is important for agricultural applications to help farmers manage their irrigation systems more efficiently. Knowing the exact soil moisture conditions on their fields, not only are farmers able to generally use less water to grow a crop, they are also able to increase yields and the quality of the crop by improved management of soil moisture during critical plant growth stages. ^{citation needed}

For effective irrigation, in urban and suburban areas, landscapes and residential lawns are using soil moisture sensors to interface with an irrigation controller. Connecting a soil moisture sensor to a simple irrigation clock will convert it into a effective  irrigation controller that stop  irrigation cycles when the soil is already wet.  

In the age of 15,  Priyanka has  tried to develop the system linked with Digital reading of the moisture level and link with valve to supply  water as per actual requirement of soil. The circuit diagram and related photographs are posted here which may help our friends to   develop such instrument .