SoilOptix® Blog

Measuring Soil Fertility with IoT – Smart Agriculture 

Smart agriculture is focused on soil, crop, and weather conditions. IoT sensors can measure the soil temperature, volumetric water content, sodium (N), potassium (K), phosphorous (P), photosynthetic radiation, oxygen levels, and soil water potential. The data from IoT sensors are transmitted back to the central point for measuring soil fertility, visualization, and trend analysis. The resultant data is used to optimize farming operations, identify trends, and enhance crop yield quality. IoT in agriculture is called Smart farming, and IoT is the primary component of Precision Farming.

measuring soil fertility

What Can be Measured with Smart Agriculture/IoT Sensors?

A lot of factors determine the fertility of the soil. Smart agriculture is focused on weather, soil, and crop conditions. Considering the importance of irrigation and weather, most of the smart farming solutions are coupled with Smart Water (Turbidity, Pollution, and Nutrients) and Smart Environment (Air Quality) to gain a complete solution. Measuring soil fertility with IoT sensors includes measuring the following features:

Soil Temperature

Soil temperature is a crucial aspect of belowground plants. This influences root growth, decomposition, respiration, and mineralization of nitrogen. IoT sensors estimate soil temperature by measuring the air temperature and other factors, but the most accurate measurement is using a probe buried in the soil. Based on the root structure of the plant, the probes can be installed at different depths. The surface soil temperature is measured with a different type of IoT sensor that uses IR technology.

Soil Moisture

Soil moisture content is a crucial element that determines soil fertility. Measuring soil moisture is a part of measuring soil fertility. The moisture content of the soil can be monitored using buried probes and electrodes. Soil moisture content have a crucial role in plant growth and groundwater recharge.

Soil moisture content is crucial for a lot of reasons:

1. Water in the soil serves as a crucial nutrient for every crop and nutrient.

2. Water is a critical element of photosynthesis.

3. Crop yield is highly affected by the availability of water in the soil.

4. Soil water is a crucial carrier of soluble food nutrients for plant growth.

5. Soil water also helps to regulate soil temperatures.

6. Solar Radiation

IoT sensors measure different types of solar radiation that are crucial in photosynthesis. Solar radiation can have a real impact on crop growth. IoT enables monitoring the solar levels to understand the correlations and trends. In soil radiation measurement, IoT can measure photosynthetically active radiation, UV, and shortwave.


Wind, rainfall/precipitation, humidity, and atmospheric pressure play a crucial role in crop growth. The smart agriculture systems support different advanced weather stations. The weather stations and soil sensors offer a 360-degree view of the farming operation. IoT weather stations measure the following:

1. Temperature

2. Precipitation

3. Humidity

4. Wind speed

5. Wind direction

6. Air pressure

7. Nitrogen, Phosphorous & Potassium (NPK) Soil Sensors

Nitrogen, potassium, and phosphorous sensors are new to the market, but they offer a method where the key soil nutrients can be measured using IoT sensors. NPK IoT sensors use different technologies, but a time-domain reflectory moisture sensor is a common method used by these sensors.

The combined NPK sensors can measure the following:

1. Potassium

2. Nitrogen

3. Phosphorous

4. pH

5. EC

6. Moisture

7. Temperature

When it comes to measuring soil fertility, measuring the NPK levels is extremely crucial. However, it is important to note that the NOK sensors are in the development phase. Therefore, the accuracy of the sensors might vary. The IoT sensors for agriculture measure vapor pressure and soil oxygen levels. If you are looking for the best support in measuring soil fertility, contact SoilOptix® today! Visit for details.