Infrared Spectroscopy − Moving from the Laboratory to the Field.

Infrared spectroscopy has been shown to be a powerful technique in its ability to predict a range of soil and plant properties. With the advancement of this technology, hand held versions of both NIR and MIR spectrometers are now available which can be used in the field. Two examples of where IR technology could be important in supporting agronomic decisions is the prediction of Phosphorus Buffering Index at a paddock level and the assessment of crop nitrogen status in situ. Recent studies have shown that both parameters were adequately predicted with the use of hand held instruments in the field. MIR predicted PBI values across a small section of a paddock with an accuracy of R² = 0.90. Portable NIR instruments were able to predict the N content of wheat at two growth stages with an accuracy of R² = 0.94. The performance of IR in predicting PBI and crop N content in the field was less than for processed samples in the laboratory but results are promising at an agronomic level.