The ability of the plant rhizosphere to decompose diesel range organic (DRO) compounds in soil was studied in a growth chamber. A sandy loam soil was contaminated with 2% (w/w) commercial diesel fuel, and was treated with: (a) mixed NPK fertilizer; (b) urea; (c) glucose; and (d) control (i.e., no additives). Soil was sown with either a grass mix (Poa, Phleum, and Agrostis), a legume mix (Pisum sativum and Trifolium pratense); or no vegetation; and incubated.