Scenario: Soil Compaction

It is conjectured that when fields are overgrazed by cattle there will be a substantial reduction in the available grass during the subsequent grazing season due to the compaction of the soil.A horticulturist at the state agricultural experiment station designs a study to evaluate the conjecture.Twenty-one plots of land of nearly the same soil texture and suitable for grazing are selected for the study.Three grazing regimens selected for evaluation are randomly assigned to 7 plots each.The three grazing regimens are Continuous grazing, Three-week grazing and then one-week no grazing, and Two-week grazing and two-week no grazing. After the 21 plots are subjected to the grazing regimens for four months, the researcher randomly selects 10 soil cores from each plot and measures the bulk density (g/cm³) in each soil core.The mean soil density of the 10 cores from each plot is given in the following table:

\f\fGrazing Regimen Soil Density (g/cm3) Continuous grazing 2.05 3.05 3.12 1.59 3.83 1.53 1.44 Three-week grazing, one-week no grazing 1.20 1.48 3.54 1.03 1.45 1.40 2.68 Two-week grazing, two-week no grazing 1.23 1.66 1. 70 1.29 1.26 1.05 2.35\f\f\f\f\f