Promoting Forest Recovery on a Surface Mine Site With Nutritional Amendments

Abstract

Selected nutrient amendments were evaluated for their capacity to enhance growth and nutrition of Jeffrey pine (Pinus jeffreyi Grev. & Balf.) seedlings 3 yr after planting on an acidic Sierra Nevada surface mine. The amendments were applied by topdressing at four rates each and consisted of Forestcote 22-4-6 + Minors, a controlled release formulation; Free Flow 29-3-4 and Hydro Agri 21-7-14, two conventional fertilizers with the former featuring urea as the predominant N source while that for the latter was exclusively ammoniacal and nitrate forms; and Milorganite 6-2-0 + Iron, an organic amendment derived from municipal biosolids. The Forestcote and Free Flow formulations proved most adept at reinvigorating seedling growth while Hydro Agri and Milorganite were the least stimulatory. The lowest application rates employed were inadequate but the most advantageous rate differed somewhat by formulation. Foliar analysis revealed that fertilized seedlings had more N and P but less Mn and Al than the control. Enhanced N nutrition especially, but also that of P, probably accounted for most of the growth stimulation by the amendments, as availability of both in the soil was limiting. Of the two metallic elements, reduced Mn was likely most critical because concentrations encountered here were exceedingly elevated overall, including that in the soil, although soil Al was high also. These results suggest that a variety of nutritional amendments can be employed in forest restoration on surface mine sites and those similarly degraded, including sites for which dry climates greatly influence the selection of remedial practices.

Keywords:

• forest restoration
• reforestation
• mine reclamation
• forest fertilization
• forest nutrition
• phytotoxicity
• Pinus jeffreyi

Acknowledgments

Financial support for this research was provided by the Nevada Agricultural Experiment Station and the McIntire-Stennis Cooperative Forestry Research Program. The author thanks J. Chacon, R. Fecko, G. Fernandez, W. Frederick, C. McCarthy, and J. Spurlock for their assistance.