Leaf Tissue Tests vs Soil Tests

1 November 2008

Leaf tissue tests provide a "snapshot" of plant nutrient status at the time of testing. This differs from a soil test that is designed to predict the soil’s ability to supply nutrients over a period of time.

As a result a plant and soil test from the same area will often show different patterns of deficiency and excess.

Remember that leaf analysis only reflects nutrients the soil mineral balance allows the plant to extract.  An excess of any element in the soil will always reduce the uptake of others. e.g. high magnesium will reduce the plant uptake of potassium and boron even if they are both at good levels in the soil.

The Golden Rule is “never formulate a soil fertiliser program based on a leaf test without information from a soil test as well”.

Leaf tissue results can be used to formulate foliar fertiliser programs that will feed the plant directly and bypass any soil imbalances.

Therefore always use a soil analysis for fertilising the soil and leaf analysis for immediate correction of plant deficiencies with foliars.