Inorganic nitrogen supply and dissolved organic nitrogen abundance across the US Great Plains

• Published in: PloS one Vol. 9; no. 9; p. e107775
• Main Authors: Mobley, Megan L, Cleary, Matthew J, Burke, Ingrid C
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 22.09.2014; Public Library of Science (PLoS)
• Subjects: Annual precipitation; Biology and Life Sciences; Carbon; Chlorides; Climate change; Dissolved organic nitrogen; Earth Sciences; Ecology; Ecology and Environmental Sciences; Ecosystem; Ecosystems; Grasses; Grasslands; Mean annual precipitation; Mineralization; Natural resources; Net Primary Productivity; Nitrogen; Nitrogen - analysis; Organic nitrogen; Organic soils; Physical Sciences; Plant sciences; Poaceae; Potassium chloride; Prairies; Precipitation; Primary production; Productivity; Soil - chemistry; Soil sciences; Soil surfaces; Studies; United States; New York; Great Plains; Wyoming; United States > US; Colorado
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0107775

Across US Great Plains grasslands, a gradient of increasing mean annual precipitation from west to east corresponds to increasing aboveground net primary productivity (ANPP) and increasing N-limitation. Previous work has shown that there is no increase in net N mineralization rates across this gradient, leading to the question of where eastern prairie grasses obtain the nitrogen to support production. One as-yet unexamined source is soil organic N, despite abundant literature from other ecosystems showing that plants take up dissolved soil organic N. This study measured KCl-extractable dissolved organic N (DON) in surface soils across the grassland productivity gradient. We found that KCl-extractable DON pools increased from west to east. If available to and used by plants, this DON may help explain the high ANPP in the eastern Great Plains. These results suggest a need for future research to determine whether, in what quantities, and in what forms prairie grasses use organic N to support primary production.