Research article - Peer-reviewed, 2016
Phosphorus fertilisation under nitrogen limitation can deplete soil carbon stocks: evidence from Swedish meta-replicated long-term field experiments
Poeplau, Christopher; Bolinder, Martin; Kirchmann, Holger; Kätterer, ThomasAbstract
Increasing soil organic carbon (SOC) in agricultural soils can mitigate atmospheric CO2 concentration and also contribute to increased soil fertility and ecosystem resilience. The role of major nutrients in SOC dynamics is complex, due to simultaneous effects on net primary productivity (NPP) that influence crop residue carbon inputs and in the rate of heterotrophic respiration (carbon outputs). This study investigated the effect on SOC stocks of three different levels of phosphorus and potassium (PK) fertilisation rates in the absence of nitrogen fertilisation and of three different levels of nitrogen fertiliser in the absence of PK fertiliser. This was done by analysing data from 10 meta-replicated Swedish long-term field experiments (> 45 years). With N fertilisation, SOC stocks followed yield increases. However, for all PK levels, we found average SOC losses ranging from 0.04 +/- 0.09 Mg ha(-1) yr(-1) (ns) for the lowest to 0.09 +/- 0.07 Mg ha(-1) yr(-1) (p = 0.008) for the highest application rate, while crop yields as a proxy for carbon input increased significantly with PK fertilisation by 1, 10 and 15 %. We conclude that SOC dynamics are mainly output-driven in the PK-fertilised regime but mostly input-driven in the N-fertilised regime, due to the much more pronounced response of NPP to N than to PK fertilisation. It has been established that P rather than K is the element affecting ecosystem carbon fluxes, where P fertilisation has been shown to (i) stimulate heterotrophic respiration, (ii) reduce the abundance of arbuscular mycorrhizal fungi and (iii) decrease the crop root : shoot ratio, leading to higher root-derived carbon input. The higher export of N in the PK-fertilised plots in this study could (iv) have led to increased N mining and thus mineralisation of organic matter. More integrated experiments are needed to gain a better understanding of the relative importance of each of the above-mentioned mechanisms leading to SOC losses after P addition.Keywords
Arctic charr; Heritability; GxE interactions; Growth; Skin pigmentation; AquaculturePublished in
Biogeosciences2016, volume: 13, number: 4, pages: 1119-1127
Publisher: COPERNICUS GESELLSCHAFT MBH
Authors' information
Poeplau, Christopher
Swedish University of Agricultural Sciences, Department of Ecology
Poeplau, Christopher
Thünen Institute (vTI)
Swedish University of Agricultural Sciences, Department of Ecology
Swedish University of Agricultural Sciences, Department of Soil and Environment
Swedish University of Agricultural Sciences, Department of Ecology
UKÄ Subject classification
Agricultural Science
Soil Science
Publication Identifiers
DOI: https://doi.org/10.5194/bg-13-1119-2016
URI (permanent link to this page)
https://res.slu.se/id/publ/76040