CLARK, RALPH B., SHEILA K. ZETO, RICHARD W. ZOBEL.
U.S. Department of Agriculture, Agricultural Research Service, Appalachian Soil & Water Conservation Research Laboratory, PO Box 400, Beaver WV 25813-0400 USA.
Panicum virgatum was grown in pH 4 and 5 soil inoculated with eight arbuscular mycorrhizal isolates [Glomus (G.) clarum, G. diaphanum, G. etunicatum, G. intraradices, Gigaspora (Gi.) albida, Gi. margarita, Gi. rosea, and Acaulospora (A.) morrowiae] to determine shoot acquisition of N, P, S, B, Ca, Mg, K, Mn, Fe, Zn, Cu, and Al. Compared to nonmycorrhizal (nonAM) plants, mycorrhizal plants had as high as 14-fold increases in P in pH 4 soil and as high as 3.5-fold increases in pH 5 soil. Enhanced P depended on AM isolate, and was not related to enhanced dry matter (DM). Acquisition trends for mineral nutrients were similar for AM plants grown in pH 4 and 5 soil, but differences among AM isolates were usually greater for plants grown in pH 4 than in pH 5 soil. The AM plants with enhanced DM generally had higher shoot concentrations of S, K, and Cu; similar Ca, Mg, and Zn; and lower B, Mn, Fe, and Al than nonAM. Shoot N concentration depended on AM isolate; nonAM had N as high as AM plants with highest DM. Lower shoot Al, Mn, and Fe concentrations were particularly noted for AM plants grown in pH 4 soil. Shoot mineral nutrient contents per unit root length (enhancements and reductions) varied considerably with each AM isolate. Some AM isolates were highly effective in enhancing mineral nutrients and reducing toxic elements to plants for overcoming acidic soil mineral deficiencies and toxicities.