The bean pod mottle virus (BPMV) is a virus found in soybeans spread by the bean leaf beetle. Concerned with the health of his own field of soybeans, a soybean farmer decided to conduct a small study to compare pesticides. He had 5 acres of land, far from any trees to prevent any area getting less sunlight, that he separated into 30 plots and planted 40 soybean plants per plot. He then randomly chose 10 plots to receive his usual pesticide, 10 plots to receive a new organic pesticide, and the last 10 plots were left untreated (given no pesticide). Also, to maintain constant conditions across the field, each plot was watered equally by the same farmer and using the same equipment. Once the soybean season was over, the farmer recorded the proportion of infected soybean plants from the 40 plants in each of the 30 plots.

How much replication was used in this experiment?