Performance of Alfalfa Clones in Crude Oil Contaminated Soils

W.L. Rooney¹, C.C. Wiltse¹, Z. Chen² , A.P. Schwab¹, and M.K. Banks²
Depts. of ¹Agronomy and ²Civil Engineering
Kansas State University, Manhattan, KS 66506

Phytoremediation of crude oil contaminated soils may be the most economical means of cleaning contaminated soils. In studies to compare the phytoremediation potential of different species, alfalfa was effective in the remediation of crude oil contaminated soil. Given the highly heterozygous nature of alfalfa, it is likely that variability exists for performance of individual alfalfa plants in crude oil contaminated soil. The objectives of this study were to determine if agronomic varies in contaminated soil between selected alfalfa clones, and (2) to determine if differences exist between clones for TPH degradation rates in the soil. In a twelve month greenhouse experiment, agronomic and soil contaminant data were collected for twenty alfalfa genotypes from the cultivar 'Riley'. Significant variability was detected between genotypes grown in contaminated soil for forage yield, plant height and maturity at clipping. Forage yield in the contaminated soil was only 33% of the forage yield of the same clones in uncontaminated soil. Total petroleum hydrocarbon degradation was highly correlated with total forage yield and TPH levels were lower in vegetated pots than in unvegetated controls. The results indicate that overall growth and vigor are reduced in contaminated soil, but that suitable variability exists among genotypes in contaminated soil that selection for improved performance is feasible. High correlations between plant growth and TPH degradation rates indicate that selection for enhanced degradation may be accomplished by selection of the plants with the highest forage yields.

1995 Central Alfalfa Improvement Conference Proceedings