To help farmers adapt to changing soil conditions, they are using water and soil sensors, such as soil moisture sensors, to detect how much moisture is in the soil. In the past, farmers collected soil and water conditions from the field by scouting and collecting soil and plant samples. The samples are sent to a laboratory for testing, and the results can take precious weeks.

Application of sensor

Today, because of recent developments in soil and water monitoring, the critical information is being received in real-time measurements from the field, helping farmers make faster, more accurate crop production decisions.

Farmers are now using sensors to monitor particular sectors of the field, enabling them to react quickly to changes in the land and crops. The use of smaller and less-complex sensors is making quick response possible. This allows farmers to turn soil sensor readings, weather, and historical crop data into actionable perception by seeing the bigger picture.

Soil is never consistent across a field and this inconsistency is often amplified at the sensor level. Multiple sensors can statistically improve the accuracy and track the active changes, which are variable across a field. A wet area in the spring may become dry later as the crop grows and uses up the water. Sensor-based measurements are providing more specifics, such as moisture levels, fertilizer effectiveness, and plant reaction to variable conditions, including temperature and light. These sensor measurements permit farmers to take action when a field condition, such as low water levels, produces a stress reaction.

Soil Moisture Sensors in Agriculture

Soil moisture sensors estimate the volume of water content based on the dielectric constant of the soil. The dielectric constant indicates the soil’s capability to transmit electricity. As the water content of the soil increases, the dielectric constant of the soil increases, because the dielectric constant of water is much larger than the other soil components, including air. Therefore, the measurement of the dielectric constant gives a predictable assessment of water content.

Most soil sensors are single-point sensors. They take a measurement at a single location. A single point sensor can measure soil moisture and temperature, or soil moisture, temperature and salinity. The sensor can be completely buried in the soil. Some sensors measure volumetric water content for the length of the sensor.

Soil water potential sensor measure soil moisture across a vertical soil profile, covering a range of one foot to four feet. Soil water potential sensor comprise of multiple single-point sensors contained in an elongated enclosure.

It’s important to measure soil moisture at multiple depths in order to optimize irrigation, as it indicates the penetration of water all through the root zone. The main benefit of using a soil profiling probe is the reduction of costs of installing multiple single-point sensors, and the requirement to dig a large hole to bury them at the proper depths.

Sensors that measure the volumetric water content are typically referred to as soil moisture sensors. Soil volumetric water content sensors measure the water content of soil. These sensors can be used to estimate the amount of stored water in a profile or how much irrigation is required to reach a desired amount of water in the soil. These sensors can be used for quick measurements or installed for long-term measurements.

Soil sensors are permanently buried and are left for continuous long-term monitoring if they are connected to a data logger, or wireless remote telemetry, or on-demand monitoring using a handheld reader. They can remain buried indefinitely, depending on the durability of the sensor and the cable. Portable soil sensors provide the user an instantaneous reading of soil moisture in a battery-powered, self-contained unit that can be carried anywhere. Readings are shown on an integrated display, or on the user’s smartphone, which communicates with the sensor unit through Bluetooth or WiFi.

Summary

The amount of moisture or soil water is important to know because soil water performs as a carrier of food nutrients needed for plant growth. Soil water is a nutrient by itself. The yield of a crop is most often influenced by the amount of water available rather than the deficit of other food nutrients. Water regulates soil temperatures. Microorganisms require water for their metabolic activities, while helping in the chemical and biological activities of the soil. Finally, water is essential for photosynthesis. Therefore, soil moisture sensors are critical for Agriculture.