Comparison of stirring and vortex mixing for the extraction of available nutrients from soil using a laboratory robot

Abstract

We investigated the efficiency with which a laboratory robot is able to extract available nutrients from soil contained in tubes. We have shown that for vortex mixing, the volume of soil and extractant are of critical importance. In cases where the soil/extractant volumes are small (e.g. 2 mL soil: 10 mL extractant), extraction of all the nutrients investigated was good. However, keeping the ratio the same, but increasing the volumes to 6 mL soil:30 mL extractant leads to an overall decrease in extracting efficiency. Using a paddle stirrer to mix the soil and extractant together results in the same extraction efficiency across the range of soil/ extractant volumes.

Notes

Correspondence to M. N. Quigley.