Division 2.2.2 Yield

Effects on yield are determined on the basis of two measurement variables, frond number and one other measurement variable (total frond area, dry weight or fresh weight) present in each test vessel at the start and end of the test. For dry weight or fresh weight, the starting biomass is determined on the basis of a sample of fronds taken from the same batch used to inoculate the test vessels (see second paragraph in section 1.7.3). For each test concentration and control, calculate a mean value for yield along with variance estimates. The mean percentage inhibition in yield (% I_y) may be calculated for each treatment group as follows:

$$\%I_y=\frac{(b_C\mathrm{ – }{b}_T)}{b}C\mathrm{\times \; 100}$$

where:

— % I_y:

percentage reduction in yield

— b_C:

final biomass minus starting biomass for the control group

— b_T:

final biomass minus starting biomass in the treatment group