How intelligent soil sensors can help farmers reduce fertiliser use

21-12-2021 | By Robin Mitchell

Researchers have recently developed a smart sensor that can help farmers reduce the fertiliser they use on their crops. What problems does fertiliser abuse cause, what did the researchers develop, and could it help farmers and the environment in the future?

Why fertilisers constitute a significant problem

Of all industries on the planet, the agricultural sector is arguably the single most important one for the simple reason that it produces food. But the importance of food production goes beyond the obvious use of feeding people; making the food production process efficient allows people to spend time doing other things, including research and development. In fact, the industrial revolution in the UK can be said to have only been possible thanks to improved agricultural methods, which saw food supplies increase.

Farmers deploy many methods to increase crop yields, including increased CO2 concentrations, artificial lighting, and heating. But of all these methods, the oldest method is by far the most popular, fertilisers. Before the rise of the chemical industry, fertiliser was sourced naturally from the manure of animals and humans as it is high in nutrients and organic compounds such as nitrates. However, the development of the Haber process saw synthetic ammonia being produced at industrial scales, which can be used to cheaply make fertilisers for plants.

The use of fertilisers helps give plants all the nutrition they need to grow large and healthy, but figuring out how much a plant needs can be challenging. As such, farmers typically make rough calculations as to the quantity of fertiliser needed, add some additional amount to account for spillage and leakage, and then spray an entire field uniformly.

While this works in practice, it results in large amounts of waste leaking into rivers and oceans. When fertiliser enters the environment from runoffs, the high concentration of the fertiliser can often kill plants and small animals. Furthermore, the fertiliser that is washed into rivers, lakes and oceans can increase the growth of certain organisms and plants such as algae. While this may sound like a good thing, the truth is that this can lead to too much of one kind of life, which disrupts ecosystems.

To minimise this environmental damage, farmers need to accurately disperse fertiliser where required. However, achieving this is complex and time-consuming, which could hurt a farm's profit.

Researchers develop smart sensors for better fertiliser control

Recently researchers from Guder Research Group have developed a smart farm sensor that can be directly inserted into the soil and provide farmers with insight into the condition of their soil the nutrients, and water content. The new sensor can measure ammonia levels in the soil, which directly relates to the amount of nutrition in the soil, and this data is fed into an AI. Furthermore, this data is combined with weather data the last time the field was fertilised pH and soil conductivity to create a predictive measure of how much nitrogen is in the soil.

While other sensors can measure levels in the soil, such as ammonia, the use of AI and machine learning allows this sensor to provide better insight into the soil that it is measuring. Additionally, the use of AI helps reduce the cost of the sensor while maximising its capabilities. The low-cost nature of the sensor developed will allow farmers to use such technology in mass. This will enable farmers to better understand their farm fields, how much nutrition they need to give, and where to deposit fertiliser.

Could such technology help future farmers and the environment?

There is no doubt the excessive use of fertilisers hurts the environment, which is why there are strict regulations and controls as to what farmers are allowed to dump into rivers and onto their own fields. If the technology developed by the researchers helps to minimise the amount of fertiliser used, not only will it help to improve the environment, but there will also be less demand on the environment for obtaining the resources needed to create nitrates in the first place (i.e. more minor mining operations and habitat destruction).

The device developed by the researchers will face multiple challenges, including radiocommunication, battery lifetime, feasibility, and price. Just because the device works on a small scale on a few selected farms doesn't mean that it will be practical on a global scale, but with growing pressure from environmentalists and governments to try and improve the environment, such sensing technology may become critical in the future of food production.

Once again, this technology clearly signifies the importance of AI as it can turn cheap sensors into extremely powerful systems.


By Robin Mitchell

Robin Mitchell is an electronic engineer who has been involved in electronics since the age of 13. After completing a BEng at the University of Warwick, Robin moved into the field of online content creation, developing articles, news pieces, and projects aimed at professionals and makers alike. Currently, Robin runs a small electronics business, MitchElectronics, which produces educational kits and resources.