Plant carbon substrate supply regulated soil nitrogen dynamics in a tallgrass prairie in the Great Plains, USA: results of a clipping and shading experiment

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Abstract

Aims

Land use management affects plant carbon (C) supply and soil environments and hence alters soil nitrogen (N) dynamics, with consequent feedbacks to terrestrial ecosystem productivity. The objective of this study was to better identify mechanisms by which land-use management (clipping and shading) regulates soil N in a tallgrass prairie, OK, USA.

Methods

We conducted 1-year clipping and shading experiment to investigate the effects of changes in land-use management (soil microclimates, plant C substrate supply and microbial activity) on soil inorganic N (

Methods

JOURNAL/jpec/04.02/01388114-201112000-00005/math_5MM1/v/2017-10-16T154700Z/r/image-png

Methods

and

Methods

JOURNAL/jpec/04.02/01388114-201112000-00005/math_5MM2/v/2017-10-16T154700Z/r/image-png

Methods

), net N mineralization and nitrification in a tallgrass prairie.

Important Findings

Land-use management through clipping and/or shading significantly increased annual mean inorganic N, possibly due to lowered plant N uptake and decreased microbial N immobilization into biomass growth. Shading significantly increased annual mean mineralization rates (P < 0.05). Clipping slightly decreased annual mean N nitrification rates whereas shading significantly increased annual mean N nitrification rates. Soil microclimate significantly explained 36% of the variation in

Important Findings

JOURNAL/jpec/04.02/01388114-201112000-00005/math_5MM3/v/2017-10-16T154700Z/r/image-png

Important Findings

concentrations (P = 0.004). However, soil respiration, a predictor of plant C substrate supply and microbial activity, was negatively correlated with

Important Findings

JOURNAL/jpec/04.02/01388114-201112000-00005/math_5MM4/v/2017-10-16T154700Z/r/image-png

Important Findings

concentrations (P = 0.0009), net N mineralization (P = 0.0037) and nitrification rates (P = 0.0028) across treatments. Our results suggest that change in C substrate supply and microbial activity under clipping and/or shading is a critical control on

Important Findings

JOURNAL/jpec/04.02/01388114-201112000-00005/math_5MM5/v/2017-10-16T154700Z/r/image-png

Important Findings

, net N mineralization and nitrification rates, whereas clipping and shading-induced soil microclimate change can be important for

Important Findings

JOURNAL/jpec/04.02/01388114-201112000-00005/math_5MM6/v/2017-10-16T154700Z/r/image-png

Important Findings

variation in the tallgrass prairie.

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