Soil nutrition can be ascertained via two different methods:
- Physical soil sampling and laboratory analysis
- Sensors that penetrate the soil (for specific nutrition outputs and/or nutrition lead indicators)
Physical Soil Sampling & Laboratory Analysis
The below video explains the soil sampling process.
Precision Agriculture P/L sampling vehicle
Typically, samples can be analysed in a laboratory for pH, Cation Exchange Capacity (CEC), Exchangeable Sodium Percentage (ESP) and phosphorous (Colwell and Olsen). These all then feed into precision agriculture decisions via variable rate applications of fertiliser, nutrients, and water.
Sensors
Recently companies such as Soil Optix are developing and commercialising high-resolution topsoil mapping solutions. The Gamma radiation-based sensor is mounted on a vehicle approximately 60cm of the ground. Once the sensor is mounted data will be collected when travelling up to 20km/h in 12-metre swath widths. This sensor can measure natural geological properties emitted from the soils decay, such as Caesium-137, Uranium-238, Thorium-232 and Potassium-40. These sensors are complemented physical soil sampling, during sensor calibration to each property location.
Key Points
- Precision Agriculture – soil sampling is an important and critical input for variable rate applications of fertiliser and nutrients.
- Soil sampling results can be used for an entry-level to precision agriculture even without fully automated and integrated spreaders.