Proximal sensing technologies on soils and plants in the Eyre Peninsula
Irregular and infrequent winter rainfall patterns coupled with low soil fertility provide a challenging environment for growers in the Upper Eyre Peninsula (UEP). Proximal sensing (PS) technologies have the potential to support growers’ nutrient management decisions by monitoring in-season variations in soil water content together with water and nutrient status of the crop. The development of small, portable PS devices has now allowed the use of this technology in the field, enabling PS to be utilised by growers in their paddocks. In this research, two years of UEP nutrition trials have been combined to calibrate PS (SR-3500 spectroradiometer from Spectral Evolution) for crop nutrient content, and one year of data has been examined for soil moisture and nutrient content. PS absorbance data predicted soil moisture and nitrogen with reasonable accuracy (R2 = 0.6-0.8) at depths (0-10, 10-30, 30-90 cm) on the upper Eyre Peninsula in 2018. In-crop PS reflectance data at stem elongation (Growth Stage 31 = GS31, Zadoks et al., 1974) predicted (R2 = 0.5-0.8) the amount of crop macronutrients, including but not limited to nitrogen, phosphorus, potassium and sulphur. Further experimental data are required to use soil absorbance and crop reflectance as a means of predicting nutrient content, because some environmental parameters can confound the results.

Authors: Fabio Arsego | Helena Oakey
Keywords: PS (proximal sensing), Upper Eyre Peninsula (UEP), crop and soil nutrients
Spectral Evolution is a leading manufacturer of field-portable UV-Vis-NIR remote sensing spectroradiometers and spectrometers for applications including geological remote sensing, ground-truthing, spectral remote sensing, environmental and climate research, crop and soil research, vegetative studies, forestry and canopy studies, radiometric calibration transfer, upwelling and downwelling measurement and more. Our UV-Vis-NIR spectrometers and spectroradiometers provide the best combination of high resolution and high sensitivity resulting in the most precise field portable instruments available on the market.
Spectral Evolution UV-Vis-NIR spectroradiometers provide:
- Fast, full-spectrum UV-Vis-NIR measurements – 350-2500 nm with just one scan
- Superior reliability in the field with 100% diode array optics with no moving parts
- Wireless Bluetooth® Connection
- Lithium-ion rechargeable batteries for field use
- Lightweight and rugged
- Rugged handheld tablet for field use running DARWin™ LT on Windows 10 with digital camera, and GPS
- Field switchable optics for varying target sizes and measurement modes
All Spectral Evolution UV-Vis-NIR spectroradiometers include our exclusive DARWin™ SP Data Acquisition and Analysis software for one-touch, full range spectroscopic analysis of samples. DARWin™ SP automatically saves data as ASCII files for use with 3rd party software without post-processing.