How IoT Sensors Help Farmers Monitor Soil Conditions
A farmer can walk through a field and see whether crops look healthy, but important changes are often happening below the crop canopy before they become visible. Soil may be drying faster in one section than another, irrigation water may not be reaching the intended root zone, soil temperature may be affecting germination, or electrical conductivity may change as salts or dissolved nutrients accumulate.
Traditional field inspection, soil sampling and laboratory analysis remain important tools for understanding these conditions. The problem is that they do not always provide continuous information from the field. A soil sample collected today tells the farmer something about the sampled location and time. It does not continuously show what is happening in that soil tomorrow afternoon after irrigation, rainfall or a period of intense heat.
This is where Internet of Things, or IoT, soil monitoring systems can become useful. Sensors installed in the field can collect measurements such as soil moisture and temperature and, depending on the system, other properties such as electrical conductivity or pH. A connected device can transmit those readings to a local gateway, phone, computer or cloud platform, allowing farmers and farm managers to observe changes without physically visiting every monitoring point.
The important point is that IoT does not make the soil healthier by itself. Its value comes from turning conditions that are difficult to observe continuously into usable information for irrigation, crop management, fertigation, field scouting and farm decision-making.
IoT sensors and laboratory soil testing serve different purposes.
Traditional soil testing provides a detailed analytical snapshot from collected samples. IoT sensors can provide repeated measurements from fixed field locations.
One does not necessarily replace the other.
| Approach | Main strength | Main limitation |
|---|---|---|
| Laboratory soil testing | Detailed analysis of selected soil properties | Samples represent particular locations and collection times |
| Manual field observation | Low technology requirement and direct field context | Subjective and difficult to record continuously |
| Portable soil probe | Immediate field measurements | Coverage depends on operator and sampling strategy |
| Fixed soil sensor | Continuous monitoring at selected points | Represents only the monitored locations |
| IoT-connected sensor | Continuous measurements plus remote access and alerts | Requires additional communication, power and data infrastructure |
| Remote sensing | Wider spatial coverage | Often provides indirect or model-based information rather than direct soil measurements |
The strongest farm-management system may combine several of these methods.
The physical sensor does not necessarily require internet access to measure soil conditions.
The internet or another communication network becomes important when the farmer wants remote access, cloud storage, online dashboards or alerts delivered over long distances.
A system can sometimes store data locally when connectivity is unavailable and transmit the information later. The specific capability depends on the hardware and software.
This is particularly important when evaluating technology for farms in areas where mobile coverage is inconsistent.
For farms in Nigeria and other parts of Africa, connectivity should be assessed at the actual field location rather than assumed from coverage in the nearest town. Power availability, SIM or network compatibility, battery performance, solar installation, technical support and replacement parts can all affect whether a connected system remains operational.
The main benefit is better visibility into changing field conditions.
Instead of relying entirely on occasional observations, farmers can develop a record of how soil conditions change over time. This can support irrigation scheduling, field scouting and identification of unusual conditions.
Connected systems can also reduce the need for staff to physically visit every monitoring location simply to collect a reading. Alerts can draw attention to conditions that require investigation.
For larger farms, this can become particularly useful when fields are geographically dispersed.
Research and agricultural extension guidance support the use of soil moisture information as one tool for improving irrigation management, while also emphasizing appropriate placement, interpretation and maintenance.
The potential benefits therefore include better information, more timely decisions, improved monitoring of field variability and more systematic farm records. They should not be interpreted as guaranteed water savings or yield increases.
Walk the field. Check plants, irrigation equipment, soil conditions and weather. Sensor data should complement farm knowledge rather than replace it.
If the system provides useful information and leads to better decisions, expand it to additional management zones. If it does not change farm decisions, adding more sensors may simply increase costs and maintenance.
Hypothetical Example: A Commercial Vegetable Farm
Consider a hypothetical commercial vegetable farm divided into several irrigation blocks.
The farm manager notices that irrigation duration is based largely on a fixed schedule. Some blocks have heavier soil, while others contain lighter soil. Crop growth also varies across the farm.
Instead of installing sensors everywhere, the manager establishes representative management zones. Soil moisture sensors are installed at selected depths in each zone, while a weather station provides local weather information.
The sensor readings show that one lighter-soil zone is drying faster than a heavier-soil zone. The farm manager uses this information alongside crop observations and irrigation records to adjust management.
Later, one irrigation block shows an unusual moisture response after an irrigation event. Rather than immediately assuming that the crop needs more water, the manager checks the irrigation system for pressure, flow and distribution problems.
The important lesson is that the sensors do not make the decisions themselves. They provide information that helps the farm manager investigate conditions and make better-informed decisions.
Hypothetical Example: A Small Tomato Farm
A hypothetical small tomato farmer using drip irrigation may not need a complex cloud platform with dozens of sensors.
A simpler arrangement could include a soil moisture sensor or portable probe, a basic irrigation record and rainfall observations.
The farmer could monitor soil moisture at representative points and compare the readings with crop development and irrigation history.
If the system helps the farmer avoid unnecessary irrigation or identify when the root zone is becoming too dry, it may provide useful value without requiring a large technology investment.
This is why farm size alone should not determine technology adoption. The value of the information and the cost of obtaining it are more important.
Is IoT Soil Monitoring Right for Every Farm?
No.
A farm with reliable rainfall, little irrigation and low soil variability may have limited need for continuous connected soil monitoring.
A small farm may find manual monitoring or periodic soil testing more economical.
A commercial irrigated farm with expensive water, multiple management zones and variable soil conditions may have a stronger reason to invest in continuous monitoring.
The decision should be based on the cost of the agricultural problem being managed, the quality of information required and the practical ability of the farm team to use that information.
What Farmers Should Ask an IoT Sensor Supplier
Before purchasing, farmers should ask:
- What exactly does the sensor measure?
- Does it measure the property directly or estimate it?
- What soil types has it been tested under?
- What calibration procedure is required?
- At what depths can it operate?
- How often does it record data?
- How long does the power supply normally support the system under the intended operating conditions?
- What communication networks are supported?
- What happens if the network fails?
- Is data stored locally?
- Can the farm export its data?
- Is there a recurring software or connectivity charge?
- Who owns the collected data?
- What maintenance is required?
- How often should the sensors be checked?
- Are replacement parts available locally?
- Is technical support available in the farmer’s region?
- Can the system integrate with irrigation controllers?
- What happens when a sensor fails?
- Can the system be expanded later?
These questions help the farmer evaluate the entire system rather than simply comparing sensor prices.
The Future of IoT Soil Monitoring in Agriculture
IoT soil monitoring is moving toward systems that combine several data sources rather than relying on one sensor.
Connected soil measurements can increasingly be combined with weather stations, satellite imagery, crop observations, irrigation records and farm-management software. Machine learning can then be used in some systems to identify patterns or support predictions.
Recent research continues to explore sensor fusion, edge computing, machine learning and connected soil-monitoring systems. At the same time, researchers continue to identify challenges involving sensor calibration, connectivity, data quality, interoperability and cost.
This suggests that the practical direction of the technology is not simply “more sensors.” The more useful development is better integration of reliable measurements into farm decisions.
For farmers, that means the future value of IoT soil monitoring will depend not only on sensor hardware but also on agronomic interpretation, data quality, connectivity, affordability and local technical support.
Frequently Asked Questions
What are IoT soil sensors?
IoT soil sensors are field sensors that measure soil or environmental conditions and connect their readings to a data system. Depending on the device, they may monitor soil moisture, temperature, electrical conductivity, pH or other parameters.
What is the main use of IoT soil sensors in farming?
One of the most practical uses is monitoring soil moisture to support irrigation decisions. Farmers can also use connected measurements to observe soil temperature, electrical conductivity and other conditions where suitable sensors are available.
Can IoT sensors tell farmers when to irrigate?
They can provide information that supports irrigation scheduling, particularly when soil moisture is monitored at representative locations and depths. The farmer still needs to consider crop requirements, soil conditions, rainfall, irrigation-system performance and other factors.
Do IoT soil sensors need internet?
The sensor itself can measure soil conditions without internet access. Internet or another communication network is generally needed for remote dashboards, cloud storage or alerts, although some systems can store data locally until connectivity becomes available.
Are IoT soil sensors suitable for small farms?
They can be, particularly when irrigation or another soil-management problem has a significant effect on production. Small farms may prefer a simpler sensor or monitoring service instead of installing a large connected network.
Can soil sensors replace laboratory soil testing?
Generally, they should not automatically be treated as replacements. Continuous field sensors and laboratory soil analysis provide different types of information. Important fertilizer and soil amendment decisions may still require representative laboratory testing.
How accurate are IoT soil sensors?
Accuracy varies according to sensor technology, soil properties, installation, calibration, temperature, salinity and other operating conditions. Farmers should evaluate the measurement method and verification procedure rather than assuming that every digital sensor provides laboratory-level accuracy.
Are IoT soil sensors worth the cost?
They can be worthwhile when better soil information leads to valuable management improvements. The decision depends on farm size, crop, irrigation system, soil variability, sensor cost, connectivity, maintenance and the importance of the problem being addressed.
