Single and multiple trace metal excess effects on three different plant species

Abstract

Three crops of plants (corn (Zea mays L. cv. Golden Cross N.C.). barley (Hordeum vulgare L. cv. Atlas), soybeans (Glycine max L. cv. Hawkeye and PI54619–5–1) were grown in succession in flats of Yolo loam soil which had received in μg/g soil 0, 13 Li, 200 Zn, 200 Cu, 75 Co, 100 Ni, and 100 Cd both singly and in various combinations. The three plant species with two cultivars of soybeans reacted differently to the trace metals. Protective (competitive), additive and synergistic effects were all present. The treatments slightly modified soil pH but this did not explain all effects. Barley was most tolerant of the trace metals and yield depression occurred only when all six trace metals were applied simultaneously and this probably because of metal induced P deficiency.

Key words:

• Interactions
• synergistic effects
• additive zinc
• copper
• cobalt
• lithium
• nickel
• cadmium