Chlorophyll meter use on field grown tea: 1. The optimum leaf age and measuring positions on a leaf blade.

Abstract

In a field experiment conducted in Kenya, a Hydro N-tester chlorophyll meter was used to determine the optimum age and reading position for the measurement of chlorophyll in leaves of tea (clone 6/8). Meter readings were taken from nine positions on the top surface of the leaf blade (3 positions either near the leaf base, in the middle, and near the apex), and measurements were taken from the first, second and third and mature leaves. Chlorophyll meter readings increased with increasing leaf age; for the first, second, third and mature leaf blades, meter readings were 80, 170, 350 and 790, respectively. Errors in meter readings decreased with the increase in leaf age. Errors in chlorophyll determination were within acceptable levels when measurements were taken from the third and mature leaves. Chlorophyll levels on the midrib showed significantly higher and consistent readings than those on either side of the midrib regardless of leaf age. It is concluded that the chlorophyll meter can be reliable in estimating the chlorophyll level in tea when measurements are taken at the middle part of the blade of third leaves.