Our latest soil test innovation | Hill Laboratories - NZ


Our latest soil test innovation

Date: 1 Aug 2022
Author: Hill Laboratories

In our last newsletter, we described the Hot Water Carbon (HWEC) test as a measure of the labile organic carbon pool in soils and its use as an indicator of soil health. Excitingly, Hill Laboratories are now running this HWEC test using Near Infra-Red Spectroscopy (NIRS) for routine agronomic soil samples (excluding peats), rather than the slower reference wet chemistry method.

The use of NIRS for soil tests allows quick and affordable results and has been a focus for us over the last several years. The list of soil tests we routinely run using NIRS is now quite extensive: Organic Matter (Total Carbon); Total Nitrogen; Anaerobic Mineralisable Nitrogen (AMN & AN); Total Sulphur; Extractable Organic Sulphur as well as Anion Storage Capacity.

The laboratory uses qualification statistics to monitor the prediction performance of the NIRS soil test results, and will “code-swap” to the reference method any results flagged as outliers.

There is no additional charge when this occurs, although results will be slightly delayed. Of course, the reference wet chemistry method can be carried out upon request via our quoting system. 

Our unique approach utilises our Automatic Soil Tapping Robot (ASTRO), so that every soil sample is scanned in-line and the NIRS spectra saved. In this way, we are able to retrospectively provide results for the tests listed above, if needed (provided they pass the qualification criteria).


Soil tapping robot with NIRS scanning head

To find out more about our use of NIRS for soil testing, check out this Technical Note on our website. Information on the range of soil tests we offer can also be found there.