Recent excessive use of fertilizers containing nitrate has caused acidification of the soil around tea fields,
leading to environmental pollution, and this has become
a serious problem. However, it could not be determined
with certainty whether the roots would release the organic
acids needed to naturally acidify the soil as done
by most plants, even though an acidic soil is suitable for
the growth of tea plants, because soil cultivation has disturbed
the conditions for investigating the specific role of
roots in detail.