Soil compaction and arbuscular mycorrhizae affect seedling growth of three grasses

Abstract

Soil compaction is a limitation to establishment of native forest species on reclaimed surface- mined lands in Appalachia. Previously, non-na- tive forage species such as tall fescue (Sche- donorus arundinaceus (Schreb.) Dumort., nom. cons.) have been planted because they easily established on reclaimed mine soil. There is now interest in establishing robust native prairie spe- cies to enhance biodiversity and provide greater potential for root activity in the compacted soil. We conducted a 10-week glasshouse study com- paring growth of “Pete” eastern gamagrass (Trips- acum dactyloides L.), “Bison” big bluestem (An- dropogon gerardii Vitman), and “Jesup MaxQ” tall fescue at soil bulk densities (BD) of 1.0, 1.3, and 1.5 g·cm−3. We also examined effects of ar- buscular-mycorrhizal fungi (AMF) on plant growth in relation to compaction. Sources of AMF were a reclaimed surface coal mine soil and a native tallgrass prairie soil. Shoot and root biomass of tall fescue and big bluestem were reduced at 1.5 BD while eastern gamagrass growth was not af- fected. Growth of big bluestem and eastern ga- magrass was greater with AMF than without, but similar between AMF sources. Tall fescue growth was not enhanced by AMF. Overall, tall fescue biomass was 3 times greater than eastern ga- magrass and 6 times greater than big bluestem when comparing only AMF-colonized grasses. Eastern gamagrass and big bluestem are both slower to establish than tall fescue. Eastern ga- magrass appears to be more tolerant of com- paction, while big bluestem appears somewhat less tolerant.