TY - JOUR

T1 - N14C

T2 - a plant-soil nitrogen and carbon cycling model to simulate terrestrial ecosystem responses to atmospheric nitrogen deposition

AU - Tipping, Edward

AU - Rowe, E. C.

AU - Evans, Claire D.

AU - Mills, Robert T. E.

AU - Emmett, Bridget A.

AU - Chaplow, J. S.

AU - Hall, Jeremy R.

PY - 2012/12

Y1 - 2012/12

N2 - The dynamic model N14C simulates changes in the plant-soil dynamics of nitrogen and carbon, brought about by the anthropogenic deposition of nitrogen. The model operates with four plant functional types; broadleaved and coniferous trees, herbs and dwarf shrubs. It simulates net primary production (NPP). C and N pools, leaching of dissolved organic carbon and nitrogen (DOC, DON) and inorganic nitrogen, denitrification, and the radiocarbon contents of organic matter, on an annual timestep. Soil organic matter (SOM) comprises three pools, undergoing first-order decomposition reactions with turnover rates ranging from c. 2 to c. 1000 years. Nitrogen immobilisation by SOM occurs if inorganic N remains after plant uptake, and leaching of inorganic N occurs if the immobilisation demand is met. SOM accumulates in the deeper soil by transport and sorption of DOM. Element soil pools accumulate with N inputs by fixation from 12,000 years ago until 1800, when anthropogenic N deposition begins. We describe the parameterisation of N14C with data from 42 published plot studies carried out in northern Europe, plus more general information on N deposition trends, soil radiocarbon, N fixation and denitrification. A general set of 12 parameters describing litter fractionation. N immobilisation, growing season length, DOC and DON leaching, denitrification and NH4 retention was derived by fitting the field data. This provided fair agreements between observations and simulations, which were appreciably improved by moderate (+/-20%) adjustments of the parameters for specific sites. The parameterised model gives reasonable blind predictions of ecosystem C and N variables from only temperature, precipitation, N deposition, and vegetation type. The results suggest an approximate doubling of NPP due to N deposition, although the majority of the sites remain N-limited. For a given N deposition, leaching rates of inorganic N at conifer and shrub sites exceed those at broadleaf and herb sites. (C) 2012 Elsevier B.V. All rights reserved.

AB - The dynamic model N14C simulates changes in the plant-soil dynamics of nitrogen and carbon, brought about by the anthropogenic deposition of nitrogen. The model operates with four plant functional types; broadleaved and coniferous trees, herbs and dwarf shrubs. It simulates net primary production (NPP). C and N pools, leaching of dissolved organic carbon and nitrogen (DOC, DON) and inorganic nitrogen, denitrification, and the radiocarbon contents of organic matter, on an annual timestep. Soil organic matter (SOM) comprises three pools, undergoing first-order decomposition reactions with turnover rates ranging from c. 2 to c. 1000 years. Nitrogen immobilisation by SOM occurs if inorganic N remains after plant uptake, and leaching of inorganic N occurs if the immobilisation demand is met. SOM accumulates in the deeper soil by transport and sorption of DOM. Element soil pools accumulate with N inputs by fixation from 12,000 years ago until 1800, when anthropogenic N deposition begins. We describe the parameterisation of N14C with data from 42 published plot studies carried out in northern Europe, plus more general information on N deposition trends, soil radiocarbon, N fixation and denitrification. A general set of 12 parameters describing litter fractionation. N immobilisation, growing season length, DOC and DON leaching, denitrification and NH4 retention was derived by fitting the field data. This provided fair agreements between observations and simulations, which were appreciably improved by moderate (+/-20%) adjustments of the parameters for specific sites. The parameterised model gives reasonable blind predictions of ecosystem C and N variables from only temperature, precipitation, N deposition, and vegetation type. The results suggest an approximate doubling of NPP due to N deposition, although the majority of the sites remain N-limited. For a given N deposition, leaching rates of inorganic N at conifer and shrub sites exceed those at broadleaf and herb sites. (C) 2012 Elsevier B.V. All rights reserved.

KW - Atmospheric deposition

KW - Carbon

KW - Leaching

KW - NPP

KW - Nitrogen

KW - Radiocarbon

KW - Soil

KW - Turnover

KW - DISSOLVED ORGANIC-CARBON

KW - TEMPERATE FOREST ECOSYSTEMS

KW - LITTER DECOMPOSITION

KW - NATURAL ECOSYSTEMS

KW - EUROPEAN FORESTS

KW - FOLIAR NITROGEN

KW - GLOBAL PATTERNS

KW - N-DEPOSITION

KW - MATTER

KW - SATURATION

U2 - 10.1016/j.ecolmodel.2012.08.002

DO - 10.1016/j.ecolmodel.2012.08.002

M3 - Journal article

VL - 247

SP - 11

EP - 26

JO - Ecological Modelling

JF - Ecological Modelling

SN - 0304-3800

ER -