Soil moisture is monitored through the water content in the soil. The soil-matrix potential is gauged by determining the force necessary to bring up water to the plant roots from the soil. Tensiometers and blocks for resistance of electricity are employed for this purpose. These sensors are useful for a variety of soils and they are very cost effective in the sense that they do not cost more than a hundred dollars a piece.
Tensiometers may necessitate the presence of a person to read the gauging on field, while the blocks for resisting electricity don’t require any kind of maintenance. There is a limitation as they may not be able to provide accurate data on wet soil conditions.
Content of water in the soil is measured both gravimetrically and volumetrically, while gravimetric monitoring does not use any kind of sensors and depend only on traditional manual practices. On the other hand volumetric measurement uses both sensors and manual efforts, which is the most popular method.
Selecting a proper soil sensor can be a difficult proposition. If you are sure of what you want, the process of selection becomes easy. You have to decide whether you require the data instantly and wherever you are placed, or whether you want samples in various places of the field or only in just a few areas, the depth at which you want the content to be measured and such other factors will determine the kind of sensors to deploy.
There are various types like in-ground sensors which are tethered to data loggers as well as portable in-ground sensors. In-ground wireless sensors are cheap and can be trusted for accurate data measurements. The soil sensors usually cost around $200 as a package, and additional sensors will cost around $75 each.
These sensors are equipped with cables running underground, so during certain operations on the field such as aerating they have to be removed and re-installed.