Growth of Rye Grass and Fescue as Affected by Lead‐Cadmium‐Fertilizer Interaction

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AbstractRye grass (Lolium perenne L.) and red fescue (Festuca rubra L.) were grown from seed in fertilized (NPK, 12:6:6) and unfertilized Flanagan silt loam soil treated with Pb (0, 10, 100, 1,000, 5,000, 10,000 µg g−1), Cd (0, 0.1, 1, 10, 50, 100 µg g−1), or a combination of Pb plus Cd at a ratio of 100 Pb:1 Cd. Plant growth and heavy metal content of plants were measured at the end of three, consecutive, 10‐day periods. Growth of Pb‐treated plants did not begin to decrease until treatment concentrations reached 1,000 µg g−1 Pb or above. Above a treatment concentration of 1,000 µg g−1 Pb with or without added Cd, growth was reduced sharply in a log‐linear fashion with increasing treatment concentrations. Some reduction in growth of plants treated with Cd alone occurred for fertilized rescue above 10 µg g−1 Cd but not for rye until treatments above 50 µg g−1. No reduction in growth was found for nonfertilized plants treated with Cd alone at the highest soil concentration (100 µg g−1). Reduction in growth for plants treated with Pb + Cd was no lower than that of plants treated with Pb alone. While fertilization stimulated growth at treatment concentrations < 1,000 µg g−1, it did not ameliorate the effects of Pb at higher concentrations. Fertilization reduced Pb content and uptake in rye (P < 0.001) but not in fescue. The Cd content of fertilized plants was greater (P < 0.05) than that of nonfertilized plants. Cadmium content of plants treated with Pb + Cd was greater (P < 0.05) than that of plants treated with Cd alone, while there was no difference in Pb content between Pb and Pb + Cd treatments.