Reclamation Effects on Mycorrhizae and Productive Capacity of Flue Gas Desulfurization Sludge
- G. W. T. Wilson,
- B. A. D. Hetrick * and
- A. P. Schwab
Ten years after portions of a dewatered flue-gas desulfurization sludge pond has been reclaimed by seeding and fertilizing, the productive capacity of reclaimed sites was higher than abandoned sites. Mycorrhizal symbiosis may be partly responsible for the increased productive capacity of the reclaimed sites, as indicated by the observation that the reclaimed sites had 2.4 times the number of mycorrhizal spores, 5.1 times the root colonization, and 2.2 to 28 times the inoculum potential of the abandoned sludge. In reclaimed sludge, 82 to 100% of all plants became mycorrhizal compared with 30 to 67% of plants in abandoned sludge. Through regression analysis, it was predicted that the reclaimed sludge sites would have a greater productive capacity than the abandoned sludge sites, even if all plants were mycorrhizal. To determine whether these differences in productive capacity were caused by differences in inoculum level, ecotypic variation in inocula, or host plant adaptation to the indigenous inoculum, inocula from an undisturbed soil, pot culture, and the sludges were compared on five host plants grown in the sludges and a prairie soil. While host, soil, and mycorrhizal status (with or withouot mycorrhizae) did affect herbage yield, inoculum source did not. In undisturbed soil, reclaimed sludge, and abandoned sludge, mycorrhizal C3 plants were 7, 71, and 90% larger, and C4 plants were 1300, 1100, and 600%6 larger than nonmycorrhizal plants, respectively. These studies demonstrate that reclamatio6n efforts stimulate recovery and productive capacity of disturbed sites, and that mycorrhizal symbiosis is an integral component in site recovery from disturbance.
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