A MODIFIED AUGMENTED DESIGN (TYPE 2) FOR RECTANGULAR PLOTS

A modified augmented design (type 2) is presented for the situation where subplots are long and narrow (rectangular plots). The arrangement of the whole plots is the same as in the type 1 modified augmented design, but the subplots are laid out in rows within whole plots. The number of subplots per whole plot is 5, where the centre plot is the control plot. Twelve sets of data generated from three hypothetical fertility maps were used to investigate (i) the choice of adjustment method based on ANOVA of control plots and (ii) the estimated relative efficiencies of the methods. The results showed that the choice of adjustment method based on ANOVA is satisfactory and, although the estimates of relative efficiency differed from the population values, the ranking of the estimates and that of population values was nearly identical.Key words: Augmented design, non-replicated experiment, control of soil heterogeneity