Calcium Depletion and Nutrient Recycling Processes

image of soil profile in Hubbard Brook plotsYears of acid deposition have depleted base cations from soils of the northeastern United States, influencing forest productivity and susceptibility to other stressors. We are using whole-watershed and plot-scale Ca fertilization experiments to investigate consequences for microbial activity and nutrient recycling processes. Our work has shown interesting interactions between Ca and P availability and N recycling processes, suggesting that depletion of available Ca constrains the ability of northern hardwood forest trees to control the loss of N from the ecosystem. In upcoming work we will test the general idea that Ca promotes N and C sequestration via plant- and fungal-mediated processes in the organic horizon.

Related publications:

Fahey, T.J., A.K. Heinz AK, J.J. Battles, M.C. Fisk, C.T. Driscoll, J.D. Blum, C.E. Johnson. 2016. Fine root biomass declined in response to restoration of soil calcium in a northern hardwood forest. Canadian Journal of Forest Research 46: 738-744.

Balaria, A., C.E.Johnson, P.M. Groffman, and M.C. Fisk. 2014. Effects of calcium silicate treatment on the composition of forest floor organic matter in a northern hardwood forest stand. Biogeochemistry 122: 313-326.

Groffman, P.M, and M.C. Fisk. 2011. Calcium constrains plant control over forest ecosystem nitrogen cycling. Ecology 92: 2035-2042.

Minick, K.J., M.C. Fisk, and P.G. Groffman. 2011. Calcium and phosphorus interact to reduce mid-growing season net nitrogen mineralization potential in organic horizons in a northern hardwood forest. Soil Biology and Biochemistry 42: 271-279.

Fisk, M.C., T.J. Fahey, and P.M. Groffman. 2010. Carbon resources, soil organisms, and nitrogen availability: landscape patterns in a northern hardwood forest. Forest Ecology and Management 260: 1175-1183.