Foliar Analysis Test

The foliar analysis test is a tool for monitoring the nutritional composition of the leaf.

This composition of percentage by weight of each element, in addition to being a function of the fertility of the substrate and the availability of nutrients, will be a function of the different species sampled.

Thus, for example, potassium in the leaf tissue of the Paspalum is in greater proportion than in the Agrostis.

We can see the general nutrient ranges in leaf tissues (Jones, 1980):

Element Ranges (%/ppm)

1. N 2.75 - 3.5
2. P 0.3 - 0.55
3. K 1 - 2.5
4. Ca 0.5 - 1.25
5. Mg 0.2 - 0.6
6. S 0.2 - 0.45
7. Fe 35 - 100 ppm
8. Mn 25 - 150 ppm
9. Zn 20 - 55 ppm
10. Cu 5 - 20 ppm
11. B 10 - 60 ppm

At low concentrations (c), leaf growth is proportional to leaf concentration up to maximum yield (d), where an increase in concentration does not give more yield, and therefore nutrient input would be wasted. At the limit it would lead to toxicities (e). At excessively low concentration levels, the correlation is inverse (a-b).