Fig. 4. One-to-one graph of the number of seed per square meter in the ZeroN treatment (x axis) plotted against the number of seed per square meter in the PlusN treatment (y axis) across all management practices (years, cultivars, herbicide, and Mn treatments) and irrigation environments (irrigated and nonirrigated). The data points represent 35 paired (ZeroN vs. PlusN) samples (i.e., 70 observations with four replications each).