Michael R. Norland

Field responses to added organic matter, arbuscular mycorrhizal fungi, and fertilizer in reclamation of taconite iron ore tailing

A three season study was conducted to determine the effect of added composted yard waste, arbuscular mycorrhizal (AM) fungi, and fertilizer on plant cover, standing crop biomass, species composition, AM fungal infectivity and spore density in coarse taconite iron ore tailing plots seeded with a mixture of native prairie grasses. Plant cover and biomass, percent seeded species, mycorrhizal infectivity and spore density were greatly increased by additions of composted yard waste. After three seasons, total plant cover was also greater in plots with added fertilizer. Third season plant cover was also greater in plots amended with the higher rate (44.8 Mg ha−1) of compost than the moderate rate (22.4 Mg ha-1). Field inoculation with AM fungi also increased plant cover during the second season and infectivity during the first two seasons. Seeded native species, consisting mostly of the cover species Elymus canadensis, dominated plot vegetation during the second and third seasons. Dispersal of AM fungal propagules into nonmycorrhizal plots occurred rapidly and increased infectivity in compost-amended plots during the third season. In plots with less than 10% plant cover, AM fungal infectivity of inoculated plots was greatly reduced after the second season. The high level of plant cover and the trend of increasing proportion of mycorrhizal-dependent warm-season grasses, along with increases in infectivity, forecast the establishment of a sustainable native grass community that will meet reclamation goals.

Revegetation of coarse taconite iron ore tailing using municipal solid waste compost

Abstract On Minnesotas Mesabi Iron Range, coarse taconite iron ore tailing is often used as the principal material in the construction of dams for large tailing impoundments. Mineland reclamation rules in Minnesota require that tailing dams be vegetated to control erosion for dam stability and safety. Coarse taconite iron ore tailing is characterized chemically by an alkaline pH, low organic matter content, lack of plant-essential nutrients, and low cation-exchange capacity; physically by its coarse texture, lack of structure, low water-holding capacity, and dark color; and biologically by a lack of microorganisms. To investigate the potential of composted municipal solid waste to ameliorate these conditions and make the material more amenable to plant establishment and growth, the US Bureau of Mines implemented a series of factorial experiments at two active taconite mine sites in northeastern Minnesota. At each experimental site, vegetative cover has improved depending on the type of municipal solid waste compost used and rate of application. At site I, overall plant cover across all treatments has improved from zero prior to experimental manipulation to 72% after four years, with seven treatment combinations exceeding 90% cover. At site II, overall plant cover has improved from zero prior to experimental manipulation to 83% after four years, with 23 treatment combinations exceeding 90% cover. At both sites, total cover has progressively increased over four years and has not reached steady-state conditions. These results suggest a possible new strategy for reclaiming difficult sites through the use of municipal solid waste compost.

RESTORING WETLAND FORM AND FUNCTION TO EVERGLADES BORROW PITS

Miami Oolitic limestone is the only significant construction material in south Florida. Limestone was mined in Everglades National Park and used as subgrade in road construction, pads for permanent buildings, and berms and above ground bunkers at a Nike Missile Base site constructed followed the Cuban Missile Crisis. Deep lakes and borrow pits are not part of the natural landscape of the Everglades. The deep borrow pits are biologically unproductive and functionally impaired. Biological form and function are lost when deep lakes replace wet prairie and shallow marsh habitats. As part of an ongoing wetland restoration program in Everglades National Park, borrow pits in the Long Pine Key District of the Park are being restored to shallow marsh habitat using artificially created substrate. This poster paper describes the planning, engineering, construction, and environmental monitoring (wetland form and function) of a restored borrow pit in Everglades National Park. Additional