An abandoned feedlot was cropped to corn (Zea mays L.) and alfalfa (Medicago sativa L.) to prevent excess buildup and deep percolation of NO3-N from the organic and NH4-N accumulations from the feedlot operation. To eliminate part of the N and salt accumulations, 15 cm of surface material was removed from half the plots and replaced with field soil. Alfalfa production was 14.1 and 11.8 metric tons/ha, and corn forage production was 8.0 and 6.7 metric tons/ha, from the intact surface and removed surface treatments, respectively. Nitrogen uptake was two and one-half to three times greater for alfalfa than for corn, which was reflected by the NO3-N content of the respective soil profiles. Nitrate-N content of the corn forage exceeded 2000 ppm (above the acceptable limit for livestock consumption), whereas the alfalfa averaged only 857 ppm, which would allow using it as a feed without ensiling. Nitrate buildup in the soil profiles was greater when the surface material remained in place; our results indicated that with proper cropping, however, either method would prevent excess NO3-N accumulation.