Crops grow best at a suitable pH. Different crops have different optimum pH. Low pH often causes problems because toxic aluminium salts become soluble, and some pathogens can thrive. Higher pH can often lead to nutrient lock up and free lime can have an effect on quality. The main causes of pH variability are soil texture and previous liming technique. The latter tends to be more noticable than the former. The United Kingdom is made up from many different types of parent soil material. The exact method employed to correct uneven pH will depend upon the natural acidity of the soils and the crops being grown on them. Liming is generally done on a rotational basis, and a fully thought out and planned sampling and application process should be considered as a high priority in any precision farming system.
This image shows how the trace element availability changes with increasing pH. The target pH that we recommend is between 6.2 -6.4, as this is where most elements are readily available.