CROPPING AN ABANDONED FEEDLOT TO PREVENT DEEP PERCOLATION OF NITRATE-NITROGEN

Crops of maize and alfalfa were grown on land previously used as a feedlot to prevent excess build-up and deep percolation of nitrate-nitrogen from the organic and ammonia-nitrogen accumulations resulting from such practices. Two trials were carried out: cropping on plots with and without the top 15 cms of soil being replaced by field topsoil from elsewhere. Alfalfa proved to be the more successful crop, and although nitrate build-up was greater when the surface material was not removed, both crops appear to be effective in preventing excess nitrate-nitrogen accumulation.