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Nitrogen dynamics in grain crop and legume pasture systems under elevated atmospheric carbon dioxide concentration: A meta-analysis.
- Source :
- Global Change Biology; Sep2012, Vol. 18 Issue 9, p2853-2859, 7p, 1 Chart, 4 Graphs
- Publication Year :
- 2012
-
Abstract
- Understanding nitrogen (N) removal and replenishment is crucial to crop sustainability under rising atmospheric carbon dioxide concentration ([ CO<subscript>2</subscript>]). While a significant portion of N is removed in grains, the soil N taken from agroecosystems can be replenished by fertilizer application and N<subscript>2</subscript> fixation by legumes. The effects of elevated [ CO<subscript>2</subscript>] on N dynamics in grain crop and legume pasture systems were evaluated using meta-analytic techniques (366 observations from 127 studies). The information analysed for non-legume crops included grain N removal, residue C : N ratio, fertilizer N recovery and nitrous oxide (N<subscript>2</subscript>O) emission. In addition to these parameters, nodule number and mass, nitrogenase activity, the percentage and amount of N fixed from the atmosphere were also assessed in legumes. Elevated [ CO<subscript>2</subscript>] increased grain N removal of C<subscript>3</subscript> non-legumes (11%), legumes (36%) and C<subscript>4</subscript> crops (14%). The C : N ratio of residues from C<subscript>3</subscript> non-legumes and legumes increased under elevated [ CO<subscript>2</subscript>] by 16% and 8%, respectively, but the increase for C<subscript>4</subscript> crops (9%) was not statistically significant. Under elevated [ CO<subscript>2</subscript>], there was a 38% increase in the amount of N fixed from the atmosphere by legumes, which was accompanied by greater whole plant nodule number (33%), nodule mass (39%), nitrogenase activity (37%) and %N derived from the atmosphere (10%; non-significant). Elevated [ CO<subscript>2</subscript>] increased the plant uptake of fertilizer N by 17%, and N<subscript>2</subscript>O emission by 27%. These results suggest that N demand and removal in grain cropping systems will increase under future CO<subscript>2</subscript>-enriched environments, and that current N management practices (fertilizer application and legume incorporation) will need to be revised. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 13541013
- Volume :
- 18
- Issue :
- 9
- Database :
- Complementary Index
- Journal :
- Global Change Biology
- Publication Type :
- Academic Journal
- Accession number :
- 78321960
- Full Text :
- https://doi.org/10.1111/j.1365-2486.2012.02758.x