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Effects of elevated atmospheric CO2 concentrations, clipping regimen and differential day/night atmospheric warming on tissue nitrogen concentrations of a perennial pasture grass.

Volder A, Gifford RM, Evans JR - AoB Plants (2015)

Bottom Line: Both warming treatments increased leaf N concentrations under ambient CO2 concentrations, but did not significantly alter leaf N concentrations under elevated CO2 concentrations.Nitrogen resorption from leaves was decreased under elevated CO2 conditions as well as by more frequent clipping.Overall, the effects of CO2, warming and clipping treatments on aboveground tissue N concentrations were much greater than on belowground tissue.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Sciences, University of California - Davis, Davis, CA, USA avolder@ucdavis.edu.

No MeSH data available.


Effect of atmospheric CO2 concentration (A), clipping frequency (B) and warming treatment (C) on fine root N concentrations at three harvest dates and three depths. HN = +2.2/+4.0 °C day/night, CW = +3.0 °C continuous warming. Different letters indicate statistically significant differences within a harvest date at P < 0.05 using Student's t LSD test.
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PLV094F6: Effect of atmospheric CO2 concentration (A), clipping frequency (B) and warming treatment (C) on fine root N concentrations at three harvest dates and three depths. HN = +2.2/+4.0 °C day/night, CW = +3.0 °C continuous warming. Different letters indicate statistically significant differences within a harvest date at P < 0.05 using Student's t LSD test.

Mentions: Fine root N concentrations decreased strongly with depth in the soil on all three harvest dates (Fig. 6, Table 2). Elevated atmospheric CO2 had no systematic effect on fine root N concentration, although there was a small significant decline under high CO2 in March 2003, in the 20–30 cm soil depth (Fig. 6A). Increased clipping frequency had no overall effect on fine root N concentration but did increase fine root N concentration in just the 0–10 cm soil layer in March 2003 (Fig. 6B). Overall, averaged across CO2, clipping frequency and harvests, warming was without effect on root N concentration. However, small effects of warming varied with depth and date and were limited to the shallower (0–10 and 10–20 cm) soil depths (Fig. 6C). In February 2002, high night-time warming led to slightly increased fine root N concentration compared with continuous warming in the 0–10 and 10–20 cm soil depths, while in March 2003, continuous warming led to higher fine root N concentrations in the continuous warming treatment compared with ambient warming in the 0–10 cm soil depth (Fig. 6C). At the final harvest (March 2003), where we also collected deeper soil cores, fine root N concentration decreased further with soil depth below 50 cm. There was a strong atmospheric CO2 concentration × depth interaction effect , Table 2) where elevated atmospheric CO2 levels reduced fine root N concentrations at the 10–20, 20–30 and 50–60 cm core depths, but not in the 0–10 and 80–90 cm core depths (Fig. 7). There were no additional effects of clipping frequency or air warming on fine root N of roots growing below 50 cm soil depth (Fig. 7B and C).Table 2.


Effects of elevated atmospheric CO2 concentrations, clipping regimen and differential day/night atmospheric warming on tissue nitrogen concentrations of a perennial pasture grass.

Volder A, Gifford RM, Evans JR - AoB Plants (2015)

Effect of atmospheric CO2 concentration (A), clipping frequency (B) and warming treatment (C) on fine root N concentrations at three harvest dates and three depths. HN = +2.2/+4.0 °C day/night, CW = +3.0 °C continuous warming. Different letters indicate statistically significant differences within a harvest date at P < 0.05 using Student's t LSD test.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
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PLV094F6: Effect of atmospheric CO2 concentration (A), clipping frequency (B) and warming treatment (C) on fine root N concentrations at three harvest dates and three depths. HN = +2.2/+4.0 °C day/night, CW = +3.0 °C continuous warming. Different letters indicate statistically significant differences within a harvest date at P < 0.05 using Student's t LSD test.
Mentions: Fine root N concentrations decreased strongly with depth in the soil on all three harvest dates (Fig. 6, Table 2). Elevated atmospheric CO2 had no systematic effect on fine root N concentration, although there was a small significant decline under high CO2 in March 2003, in the 20–30 cm soil depth (Fig. 6A). Increased clipping frequency had no overall effect on fine root N concentration but did increase fine root N concentration in just the 0–10 cm soil layer in March 2003 (Fig. 6B). Overall, averaged across CO2, clipping frequency and harvests, warming was without effect on root N concentration. However, small effects of warming varied with depth and date and were limited to the shallower (0–10 and 10–20 cm) soil depths (Fig. 6C). In February 2002, high night-time warming led to slightly increased fine root N concentration compared with continuous warming in the 0–10 and 10–20 cm soil depths, while in March 2003, continuous warming led to higher fine root N concentrations in the continuous warming treatment compared with ambient warming in the 0–10 cm soil depth (Fig. 6C). At the final harvest (March 2003), where we also collected deeper soil cores, fine root N concentration decreased further with soil depth below 50 cm. There was a strong atmospheric CO2 concentration × depth interaction effect , Table 2) where elevated atmospheric CO2 levels reduced fine root N concentrations at the 10–20, 20–30 and 50–60 cm core depths, but not in the 0–10 and 80–90 cm core depths (Fig. 7). There were no additional effects of clipping frequency or air warming on fine root N of roots growing below 50 cm soil depth (Fig. 7B and C).Table 2.

Bottom Line: Both warming treatments increased leaf N concentrations under ambient CO2 concentrations, but did not significantly alter leaf N concentrations under elevated CO2 concentrations.Nitrogen resorption from leaves was decreased under elevated CO2 conditions as well as by more frequent clipping.Overall, the effects of CO2, warming and clipping treatments on aboveground tissue N concentrations were much greater than on belowground tissue.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Sciences, University of California - Davis, Davis, CA, USA avolder@ucdavis.edu.

No MeSH data available.