Nursery Nitrogen Loading Improves Field Performance of Bareroot Oak Seedlings Planted on Abandoned Mine Lands

Abstract

Abstract Although mine reclamation sites are important targets for ecological restoration, they are generally difficult to regenerate successfully. We evaluated the importance of nursery nutrient loading as a new approach to enhance forest restoration on abandoned mine lands. Northern red oak (Quercus rubra) and White oak (Q. alba) seedlings were nitrogen (N) loaded for 18 weeks at a bareroot nursery in southern Indiana, United States. Fertility treatments followed conventional or modified exponential functions to synchronize N supply with plant demand. Subsequently, nursery‐grown seedlings were outplanted the following year onto a mine reclamation site in southwestern Indiana to evaluate effects of nursery N loading on first‐year field performance. Nursery N loading promoted total plant dry mass production 25–129% in Red oak and 50–184% in White oak compared to unfertilized plants. Nitrogen loading increased N content 88–145% and potassium (K) content 16–71% for Red oak and N content 124–250% and K content 16–93% for White oak relative to controls. When outplanted, N loading resulted in high seedling survival (>84%) and increased total plant dry mass production 14–30% for Red oak and 23–52% for White oak. Nitrogen loading increased plant N uptake 14–102% in Red oak and 32–105% in White oak under field conditions. Exponential N loading demonstrates potential as a viable technique to improve seedling outplanting performance and reclamation success in Indiana and elsewhere.