Small changes in water levels and groundwater nutrients alter nitrogen and carbon processing in dune slack soils

Abstract

Article (refereed) -postprintRhymes, J.; Jones, L.; Wallace, H.; Jones, T.G.; Dunn, C.; Fenner, N. 2016. Small changes in water levels and groundwater nutrients alter nitrogen and carbon processing in dune slack soils.Contact CEH NORA team at noraceh@ceh.ac.ukThe NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner.© 2016 Elsevier Ltd. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This version available http://nora.nerc.ac.uk/514381/ NERC has developed NORA to enable users to access research outputs wholly or partially funded by NERC. Copyright and other rights for material on this site are retained by the rights owners. Users should read the terms and conditions of use of this material at http://nora.nerc.ac.uk/policies.html#access NOTICE: this is the author's version of a work that was accepted for publication in Soil Biology and Biochemistry. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Soil Biology and Biochemistry (2016), 99. 28-35. 10.1016/j.soilbio.2016 www.elsevier.com/ 1 This is an author-created version of the article:Rhymes, J., Jones, L., Wallace, H., Jones, T.G., Dunn, C., Fenner, N. (2016). Small changes in water levels and groundwater nutrients alter nitrogen and carbon processing in dune slack soils. Soil Biology and Biochemistry 99, 28-35. http://dx.doi.org/10.1016/j.soilbio.2016.04.018 The published version can be found at:http://www.sciencedirect.com/science/article/pii/S0038071716300554Small changes in water levels and groundwater nutrients alter nitrogen and carbon processing in dune slack soils abstraction and from eutrophication. The biological effects caused by the interactions of these pressures are poorly understood, particularly on soil processes. We used a mesocosm experiment and laboratory assays to study the impact of lowered water tables, groundwater nitrogen contamination, and their synergistic effects on soil microbial processes and greenhouse gas emissions. This study showed that just a 10 cm decrease in water table depth led to a reduction in denitrification and to a corresponding increase in soil nitrogen content. Meanwhile N2O emissions occurred for longer durations within dune slack soils subject to higher concentrations of groundwater nitrogen contamination. The results from extracellular enzyme assays suggest that decomposition rates increase within drier soils shown by the increase in β-glucosidase activity, with further sensitivity to groundwater nitrogen contamination shown by the increase in phenol oxidase activity. Dune slack soils with a 10 cm lower water table had signific...

Groundwater Depth Affects Phosphorus But Not Carbon and Nitrogen Concentrations of a Desert Phreatophyte in Northwest China

“…In this study, the soil C, N, and P concentrations at 11.0 m were significantly higher than those at 2.5 and 4.5 m in 2015 and 2016 ( Figures 2A – F ). This result is consistent with previous findings, which revealed an increase in soil N concentration with declining groundwater depth in dune slack soils ( Rhymes et al, 2016 ). An increase in soil N concentration at deep groundwater depth is likely caused by a reduction in soil moisture content, which can inhibit denitrification rates, leading to increased N retention and eutrophication effect ( Rhymes et al, 2016 ).…”

“…This result is consistent with previous findings, which revealed an increase in soil N concentration with declining groundwater depth in dune slack soils ( Rhymes et al, 2016 ). An increase in soil N concentration at deep groundwater depth is likely caused by a reduction in soil moisture content, which can inhibit denitrification rates, leading to increased N retention and eutrophication effect ( Rhymes et al, 2016 ). Similarly, we believed that dry soil with declining groundwater depth affects the movement and cycle of soil C and P, resulting in increased retention and eutrophication effect in soil C and P. Hence, soil C and P concentrations were higher at 11.0 m than at 2.5 and 4.5 m.…”

Soil C and N dynamics and hydrological processes in a maize-wheat rotation field subjected to different tillage and straw management practices

“…It is well known that soil water, C and N processes have very close interactions in soil and plant systems (Rhymes et al, 2016). Soil moisture, for example, can significantly affect plant growth and ecosystem productivity (Haghverdi et al, 2017), microbial activities (Singh et al, 2011), and greenhouse gas (GHG) emissions (Kumar et al, 2016).…”

Substantial uptake of atmospheric and groundwater nitrogen by dune slacks under different water table regimes

“…Uptake may consist of a combination of nitrogen incorporation into plant tissues, binding and uptake by the soil and microbes, and losses through denitrification. Denitrification has been found to significantly increase with N availability (Adema et al, 2005;Rhymes et al, 2016). The use of 15 N labelling to trace the fate of N would help quantify the relative magnitude of these pathways in future studies.…”

“…Table 1 -Artificial groundwater recipe compound weights added to 20L of deionised water. Table extracted from Rhymes et al (2016).…”