Solutions For 9780131905429 Chapter 3.3 Problem 1AD

To increase the fertility of the soil, several farmers grow crops like rye and plough them under the soil to increase the soil fertility. Ploughing under legumes like peas, vetch etc helps fix atmospheric nitrogen in the soil because they have rhizobium bacteria in their root nodules. The following graph shows the average yield of corn grown on fields ploughed with rye, vetch etc, and one land was left barren before growing corn.

Note: Double line on the y-axis indicates that the graph does not start with zero. This is done to fit the graph to scale.