Agri Con tests small scale pH value measurement with sensor | 08.06.2010

Are there going to be online sensors for sub-area specific maintenance fertilisation in the future? Agri Con is currently testing a pH value sensor. If this method functions and produces comparable measurement results, as are currently determined in the laboratory, a pH value map would be available for liming straight after the measurement.

Small scale pH value differences could also be recorded in much more detail with roughly 10 individual samples per hectare. As to how far the measurement system, which comes from the USA, is comparable with the procedure that has been used here up to now, is currently being investigated.

The pH value sensor takes a soil sample during the field crossing. This is brought to two pH value electrodes, which carry out the measurement. The measurement is then recorded together with the GPS coordinate. The electrodes are then cleaned with water so that the measurement can be continued with the next soil sample.

The field trials for the evaluation of this method have not yet been completed and will still take some time.

However, it is clear that the pH values can vary tremendously on a small-scale (see map on the left). It is also known that sub-optimal pH values can be associated with large losses of yield. These differences within a field are determined nowadays with small scale soil sampling and are then adequately taken into account with sub-area specific maintenance fertilisation.

Agri Con will take up this topic once more in the DLG field days this year. The trial fields will be used to show how much pH values vary even on small areas and which consequences this has for the crop stand.

Further questions about the pH value sensor, as well as variable liming, P and K fertilisation can be answered by Martin Schneider, Product management Mapping.