In 2011, Longwood Gardens in Pennsylvania installed a three-hectare, 1.6-megawatt solar field. Half was previously agriculture and half was a low-quality meadow. Following panel install, four seed mixes were installed and evaluated to determine if any mix could serve as an effective, ecologically diverse seed option for solar fields in the region. Mixes were low grass (94% Festuca sp. and 6% Trifolium hybridum), cool and warm season grass (67% Festuca sp., 16% Agrostis sp., 10% Eragrostis hirsuta, 9% Dichanthelium clandestinum), warm season grass and forb (47% Chasmanthium sp., 10% Sporobolus heterolepis, 10% Eragrostis hirsuta, 16% Agrostis sp., 6% Conoclinum coelestinum, 11% Solidago sp.), and colonizing grass (45% Chasmanthium latifolium, 20% Dichanthelium clandestinum, 20% Agrostis sp., 15% Eragrostis spectabilis). All treatments were applied to both previous land use areas. Drill seeding was used between panels, areas under panels were hand seeded, and all areas had Avena sativa as a cover crop. All areas were mowed approximately three times a year when plants began to shade the panels. Three years following, most species had little or no establishment. Eragrostis hirsuta and Conoclinum coelestinum performed the best where seeded. Seven years following, treatments resulted in little differences. Generally, forbs were crowded out by grasses and forbs that did naturalize were present before treatment installation. Fully shaded areas were dominated by the invasive Microstegium vimineum. Overall, there is no one-size-fits-all solution for seeding a solar field to improve botanical biodiversity. Results indicate success depends on past land use, microclimates, and management after seeding.
Audio/Video, Conference Presentation, SER2019
Society for Ecological Restoration