Plant and Soil

, Volume 371, Issue 1, pp 675–691

Effects of differential grazing on decomposition rate and nitrogen availability in a productive mountain grassland

Authors

    • Instituto Multidisciplinario de Biología Vegetal, (CONICET-Universidad Nacional de Córdoba)
  • Ana María Cingolani
    • Instituto Multidisciplinario de Biología Vegetal, (CONICET-Universidad Nacional de Córdoba)
    • Facultad de Ciencias Exactas, Físicas y NaturalesUniversidad Nacional de Córdoba
  • Natalia Pérez Harguindeguy
    • Instituto Multidisciplinario de Biología Vegetal, (CONICET-Universidad Nacional de Córdoba)
    • Facultad de Ciencias Exactas, Físicas y NaturalesUniversidad Nacional de Córdoba
  • Marcelo Cabido
    • Instituto Multidisciplinario de Biología Vegetal, (CONICET-Universidad Nacional de Córdoba)
    • Facultad de Ciencias Exactas, Físicas y NaturalesUniversidad Nacional de Córdoba
Regular Article

DOI: 10.1007/s11104-013-1831-9

Cite this article as:
Vaieretti, M.V., Cingolani, A.M., Pérez Harguindeguy, N. et al. Plant Soil (2013) 371: 675. doi:10.1007/s11104-013-1831-9

Abstract

Background and aims

Grazing may influence nutrient cycling in several ways. In productive mountain grasslands of central Argentina cattle grazing maintain a mosaic of different vegetation patches: lawns, grazed intensively and dominated by high quality palatable plants, and open and closed tussock grasslands dominated by less palatable species. We investigated if differences in the resources deposited on soil (litter and faeces) were associated with litter decomposition rates and soil nitrogen (N) availability across these vegetation patches.

Methods

We compared the three vegetation patches in terms of litter and faeces quality and decomposability, annual litterfall and faeces deposition rate. We determined decomposition rates of litter and faces in situ and decomposability of the same substrates in a common garden using “litter bags”. We determined soil N availability (with resin bags) in the vegetation patches. Also, we performed a common plant substrates decomposition experiment to assess the effect of soil environment on decomposition process. This technique provides important insights about the soil environmental controls of decomposition (i.e. the sum of soil physicochemical and biological properties, and microclimate), excluding the substrate quality.

Results

The litter quality and faeces deposition rate were higher in grazing lawns, but the total amounts of carbon (C) and nitrogen (N) deposited on soil were higher in tussock grasslands, due to higher litterfall in these patches. The in situ decomposition rates of litter and faeces, and of the two common plant substrates were not clearly related to either grazing pressure, litterfall or litter quality (C, N, P, lignin, cellulose or hemicellulose content). In situ litter decomposition rate and soil ammonium availability were correlated with the decomposition rates of both common plant substrates. This may suggest that difference in local soil environment among patch types is a stronger driver of decomposition rate than quality or quantity of the resource that enter the soil.

Conclusions

Our results show that, although high grazing pressure improves litter quality and increases faeces input, the reduction in biomass caused by herbivores greatly reduces C and N input for the litter decomposition pathway. We did not find an accelerated decomposition rate in grazing lawns as proposed by general models. Our results point to soil environment as a potential important control that could mask the effect of litter quality on field decomposition rates at local scale.

Keywords

Nutrient cycling Litter quality Litter quantity Grazing lawns Tussock grasslands

Supplementary material

11104_2013_1831_MOESM1_ESM.doc (148 kb)
ESM 1 (DOC 147 kb)

Copyright information

© Springer Science+Business Media Dordrecht 2013