Soil properties as key predictors of global grassland production : Have we overlooked micronutrients?

Radujković, D. and Verbruggen, E. and Seabloom, E.W. and Bahn, M. and Biederman, L.A. and Borer, E.T. and Boughton, E.H. and Catford, J.A. and Campioli, M. and Donohue, I. and Ebeling, A. and Eskelinen, A. and Fay, P.A. and Hansart, A. and Knops, J.M.H. and MacDougall, A.S. and Ohlert, T. and Olde Venterink, H. and Raynaud, X. and Risch, A.C. and Roscher, C. and Schütz, M. and Silveira, M.L. and Stevens, C.J. and Van Sundert, K. and Virtanen, R. and Wardle, G.M. and Wragg, P.D. and Vicca, S. (2021) Soil properties as key predictors of global grassland production : Have we overlooked micronutrients? Ecology Letters, 24 (12). pp. 2713-2725. ISSN 1461-023X

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Abstract

Fertilisation experiments have demonstrated that nutrient availability is a key determinant of biomass production and carbon sequestration in grasslands. However, the influence of nutrients in explaining spatial variation in grassland biomass production has rarely been assessed. Using a global dataset comprising 72 sites on six continents, we investigated which of 16 soil factors that shape nutrient availability associate most strongly with variation in grassland aboveground biomass. Climate and N deposition were also considered. Based on theory-driven structural equation modelling, we found that soil micronutrients (particularly Zn and Fe) were important predictors of biomass and, together with soil physicochemical properties and C:N, they explained more unique variation (32%) than climate and N deposition (24%). However, the association between micronutrients and biomass was absent in grasslands limited by NP. These results highlight soil properties as key predictors of global grassland biomass production and point to serial co-limitation by NP and micronutrients.