The effect of elevated atmospheric carbon dioxide concentration on the contribution of residual legume and fertilizer nitrogen to a subsequent wheat crop
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This study investigated the residual contribution of legume and fertilizer nitrogen (N) to a subsequent crop under the effect of elevated carbon dioxide concentration ([CO2]).
Field pea (Pisum sativum L.) was labeled in situ with 15N (by absorption of a 15N-labeled urea solution through cut tendrils) under ambient and elevated (700 μmol mol–1) [CO2] in controlled environment glasshouse chambers. Barley (Hordeum vulgare L.) and its soil were also labeled under the same conditions by addition of 15N-enriched urea to the soil. Wheat (Triticum aestivum L.) was subsequently grown to physiological maturity on the soil containing either 15N-labeled field pea residues (including 15N-labeled rhizodeposits) or 15N-labeled barley plus fertilizer 15N residues.
Elevated [CO2] increased the total biomass of field pea (21 %) and N-fertilized barley (23 %), but did not significantly affect the biomass of unfertilized barley. Elevated [CO2] increased the C:N ratio of residues of field pea (18 %) and N-fertilized barley (19 %), but had no significant effect on that of unfertilized barley. Elevated [CO2] increased total biomass (11 %) and grain yield (40 %) of subsequent wheat crop regardless of rotation type in the first phase. Irrespective of [CO2], the grain yield and total N uptake by wheat following field pea were 24 % and 11 %, respectively, higher than those of the wheat following N-fertilized barley. The residual N contribution from field pea to wheat was 20 % under ambient [CO2], but dropped to 11 % under elevated [CO2], while that from fertilizer did not differ significantly between ambient [CO2] (4 %) and elevated [CO2] (5 %).
The relative value of legume derived N to subsequent cereals may be reduced under elevated [CO2]. However, compared to N fertilizer application, legume incorporation will be more beneficial to grain yield and N supply to subsequent cereals under future (elevated [CO2]) climates.
KeywordsElevated [CO2] 15N labeling Below-ground legume N Residual legume N Residual fertilizer N
- Department of Primary Industries (2008) Organic farming: wheat production and marketing. Agriculture Notes. AG1075. Department of Primary Industries, Victoria, Australia. http://www.dpi.vic.gov.au/agriculture/farming-management/organic-farming/organic-crops-and-pastures/wheat-production-and-marketing. Accessed 5 February 2012
- IPCC (2007) Summary for policymakers. In: Climate Change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge and New YorkGoogle Scholar
- Isbell RF (1996) The Australian Soil Classification. Australian Soil and Land Survey Handbook. CSIRO Publishing, MelbourneGoogle Scholar
- Jones DB (1941) Factors for converting percentages of nitrogen in foods and feeds into percentages of protein. US Department of Agriculture Circular No. 183, Washington, DCGoogle Scholar
- McNeill AM (2001) Stable isotope techniques using enriched 15N and 13 C for studies of soil organic matter accumulation and decomposition in agricultural studies. In: Unkovich M, Pate J, McNeill A, Gibbs D (eds) Stable isotope techniques in the study of biological processes and functioning of ecosystems. Kluwer, Dordrecht, pp 195–218CrossRefGoogle Scholar