Nitrogen

Summary

It is well known that plant–soil interactions play an important role in determining the impact of global change phenomena on biodiversity and ecosystem functioning. Little is known, however, about the individual and relative importance for carbon (C) and nitrogen (N) cycling of non-random changes in plant and soil communities that result from global change phenomena, such as fertilization and agricultural intensification.

Link http://download-v2.springer.com.proxy.lib.iastate.edu/static/pdf/625/art...

Pathan et al. Plant Soil (2015) 387:413–424

Abstract

Plants and microorganisms intensely compete for nitrogen (N) at many stages of the terrestrial N cycle. In particular, the dissolved organic N (DON) pool, and competition for low molecular weight dissolved organic N (LMWDON) compounds such as amino acids and peptides (and LMW dissolved organic matter; LMWDOM as a whole) has received significant recent research interest. However, as LMWDON compounds contain both N and carbon (C), a question that remains is whether soil microorganisms are primarily taking up LMWDON mainly for the C or the N contained therein.

Bradford et al. 2014. Discontinuity in the responses of ecosystem processes and multifunctionality to altered soil community composition. PNAS 111:14478-14483

http://www.pnas.org/content/111/40/14478.abstract

Significance

The chemical composition of soil organic matter (SOM) is a key determinant of its biological stability. Our objective in this study was to evaluate the effects of various sources of supplemental N on the chemical composition of SOM in the fine (<5 μm) mineral fraction. Treatments were fallow, maize/soybean in rotation, and continuous maize receiving no fertilizer (maize0N), synthetic fertilizer N (maize + N), or composted manure (maize + manure).

Fellbaum et al. 2014 Fungal nutrient allocation in common mycorrhizal networks is regulated by the carbon source strength of individual host plants. New Phytologist pre-print

http://onlinelibrary.wiley.com/doi/10.1111/nph.12827/abstract

Summary

Common mycorrhizal networks (CMNs) of arbuscular mycorrhizal (AM) fungi in the soil simultaneously provide multiple host plants with nutrients, but the mechanisms by which the nutrient transport to individual host plants within one CMN is controlled are unknown.

Some of the papers are already posted but the whole issue might be of interests to many of us.

http://issuu.com/wblifesci/docs/scaling_root_processes_vsi

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature12901.html

Co-PI: Adina Howe, Folker Meyer, Galya Orr

Xu et al. 2013. A global analysis of soil microbial biomass carbon, nitrogen and phosphorus in terrestrial ecosystems. Global Ecology and Biogeography 22:737-749.

Main conclusions