Can additional N fertiliser ameliorate the elevated CO2‐induced depression in grain and tissue N concentrations of wheat on a high soil N background?. (7th April 2017)

• Record Type: Journal Article
• Authors: Tausz, M.; Norton, R. M.; Tausz‐Posch, S.; Löw, M.; Seneweera, S.; O'Leary, G.; Armstrong, R.; Fitzgerald, G. J.
• Is Part Of: Journal of agronomy and crop science. Volume 203:Number 6(2017)
• Page Start: 574
• Page End: 583
• Publication Date: 2017-04-07
• Subjects: climate change -- crop nutrition -- dryland agriculture -- grain protein -- nitrogen fertiliser; Agronomy -- Periodicals; Crop science -- Periodicals; 630.5
• DOI: 10.1111/jac.12209
• Languages: English
• ISSNs: 0931-2250

Abstract

Abstract: Elevated CO2 stimulates crop yields but leads to lower tissue and grain nitrogen concentrations [N], raising concerns about grain quality in cereals. To test whether N fertiliser application above optimum growth requirements can alleviate the decline in tissue [N], wheat was grown in a Free Air CO2 Enrichment facility in a low‐rainfall cropping system on high soil N. Crops were grown with and without addition of 50–60 kg N/ha in 12 growing environments created by supplemental irrigation and two sowing dates over 3 years. Elevated CO2 increased yield and biomass (on average by 25%) and decreased biomass [N] (3%–9%) and grain [N] (5%). Nitrogen uptake was greater (20%) in crops grown under elevated CO2 . Additional N supply had no effect on yield and biomass, confirming high soil N. Small increases in [N] with N addition were insufficient to offset declines in grain [N] under elevated CO2 . Instead, N application increased the [N] in straw and decreased N harvest index. The results suggest that conventional addition of N does not mitigate grain [N] depression under elevated CO2, and lend support to hypotheses that link decreases in crop [N] with biochemical limitations rather than N supply.