Figure 1 shows results from groundwater nitrate samples taken along the groundwater fence in the fall after crop harvest. The left half of the fence observed groundwater originating from a portion of the field that received 100 kg/ha of N applied at side-dress time to a corn crop. The right half were observations from the same corn crop receiving twice as much N fertilizer (200 kg/ha). While corn harvest showed no significant yield difference between the two plots, the water quality leaving the root zone was significantly better on the side of the field receiving the recommended 100 kg/ha of fertilizer N.

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