Soil type and bearing hype

Research by Mckinsey identified the sheer volume of produce that doesn’t make it from field to fork — and noted that cutting this figure in half could produce enough food to feed a billion extra people. To improve on this damning statistic, the agriculture industry is fighting back with a data driven approach to optimise farming, known as precision agriculture.

This high-tech farming management concept uses technology to analyse the conditions of fields at a very high resolution, enabling watering, fertilising and harvesting to be considered intelligently, on a plant-by-plant basis.

One example of precision agriculture technology is soil variance scanners. These scanners measure the electrical conductivity of soil by using magnets to determine soil type.  

Using this scanner, the humble tractor can be transformed into a data-driven farming machine.  The tractor tows the scanner, which has direct contact with the soil to measure its properties. The wheels of these scanners need to turn smoothly, as the device is required to be dragged across hectares of land with little friction. This makes bearing choice in these rotational parts crucial.

For every metre of field, farmers are primarily concerned with two things, how much water is available and how fertile is the soil. Establishing different soil types using scanners can provide actionable information on these factors. Changes in electrical conductivity indicates the soil type, for example, a clay soil has a much higher electrical conductivity than sandy soil.

Clay soil is able to retain a high nutrient saturation, whereas a sandy soil reaches nutrient saturation at a lower level. By identifying this variation, farmers can apply water and fertiliser to areas that need it, while saving these resources on areas that don’t. Using data from a soil variance scanner, management zones can be created to maximise crop yields.

Design challenges

Engineers in precision agriculture businesses are developing new and novel devices while making older agri-tech concepts more effective and profitable.

Soil variance scanners are a good example of long-standing technology that is still making headway. However, this doesn’t necessarily mean the design of these devices cannot be improved. As these devices use magnets to measure electrical conductivity, using metallic components is not an option, this includes stainless steel bearings in the scanner’s wheels.

For these devices, design engineers must source non-conductive bearings that are corrosion resistant and can take on the high-moisture environment of a farmer’s field.

Plastic bearings may seem like the obvious choice, as it is often the same material used in the scanner’s axle and wheels. Unfortunately, this bearing material has been known to wear too quickly.

A longer-lasting alternative is full ceramic bearings. With full ceramic bearings, both the rings and balls are made entirely from ceramic. These bearings are often confused with more commonly used hybrid bearings, made of steel rings and ceramic balls. Full ceramic bearings are ideal because of their non-conductive properties, alongside the material’s rigidity.

When choosing bearings for precision farming technology, there are different variants of ceramic to consider. Zirconia is a popular choice due to its high density and wide temperature range. Full ceramic bearings will generally accept 65 to 75 percent of the load of a steel bearing — essential for use in heavyweight farming machinery.

What’s more, the longer lifespan of ceramic bearings, when compared to plastic alternatives, will greatly reduce the maintenance of precision agriculture technology, such as soil scanners. Unlike plastic bearings, full ceramic bearings require little maintenance, therefore bearing replacement intervals are much longer.

Keeping soil scanners and other agri-tech equipment out in the field can only help to prevent post-harvest losses and allow farmers to produce enough food to feed the ever-growing population.

For more information on SMB Bearings’ full ceramic bearings and other bearings suitable for use in precision farming equipment, visit smbbearings.com or email sales@smbbearings.com.