Figure 4.

Box plots showing the reported data from the literature on the effects of crops within a rotation on water quality, specifically for subsurface nitrate-N losses. The 10th percentile is represented by the lower whisker, the 25th percentile is represented by the bottom of the box, the median is represented by the line in the middle of the box, the 75th percentile is represented by the top of the box, and the 90th percentile is represented by the top whisker (C = corn (Zea mays [L.]), S = soybean (Glycine max [L.] Merr.), A = alfalfa (Medicago sativa [L.]), W = winter wheat (Triticum aestivum [L.]), and O = oat (Avena sativa [L.]). There were 21 studies that reported nitrate losses for C, 12 for S, 6 for A, 1 for W, and 2 for O, for each crop either independently or within a larger rotation system.