Maize Fertilizer Experiments on the Islands of St. Vincent and Antigua

A series of experiments was designed to study the effect of concentration of three components of fertilizer on the growth of maize. All experiments contained 36 plots in four blocks of nine plots each. Half of the blocks contained the treatments 000 022 202 220 111 (twice) 113 131 311 and the other half 002 020 200 222 111(twice) 113 131 311 where the three digits represent levels of nitrogen, phosphorus and potassium, respectively, in the fertilizer applications. The treatments 000, 002, 020, 022, 200, 202, 220, 222 and 111 were included to search the usual range of fertilizer applications for an optimum; 113, 131 and 311 were added to provide clues in case the optimum lay outside the expected range (Springer, 1972). If this design is regarded as an incomplete block design, there is no great difficulty obtaining a reasonable partition of the treatment sum of squares.