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United States Department of Agriculture

Agricultural Research Service

Title: Carbon Dioxide Enrichment and Nitrogen Fertilization Effects on Cotton(gossypium Hirsutum L.) Plant Residue Chemistry and Decomposition

Authors
item Booker, Fitzgerald
item Shafer, Steven - USDA
item Caimiao, Wei - PENN STATE
item Horton, Stephanie - STATE OF NORTH CAROLINA

Submitted to: Plant and Soil
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 21, 1999
Publication Date: March 1, 2000
Citation: Booker, F.L., Shafer, S.R., Caimiao, W., Horton, S. 2000. Carbon dioxide enrichment and nitrogen fertilization effects on cotton(Gossypium hirsutum L.) plant residue chemistry and decomposition. Plant and Soil 220:89-98.

Interpretive Summary: Increased atmospheric carbon dioxide (CO2) concentration will likely cause changes in plant growth and composition that might affect soil decomposition processes. Microbial decomposition of dead plant matter in soils is of immense ecological importance, for it is through decomposition that carbon is recycled to the atmosphere as CO2, and nitrogen (N) and other nutrients are converted to forms available for plants. Factors that affect plant growth and composition, such as elevated atmospheric CO2 might indirectly affect decomposition rates, and thus affect the global carbon cycle and ecosystem nutrient cycling. The objective of this study was to test whether effects of CO2 enrichment in combination with N fertility on tissue chemistry of cotton altered microbial decomposition rates. Cotton plants were exposed to two concentrations of CO2 (ambient and twice ambient) and two levels of N fertilization (sufficient and low) within greenhouse chambers for 8 wks. Respiration rates of a sandy soil mixed with tissues from the various treatments were suppressed 16% by elevated CO2 and low N fertilization during the early phase of decomposition. This occurred because elevated CO2 and low soil N decreased tissue N concentration and increased tissue C:N ratio. Cumulative soil respiration after 44 d of incubation was not significantly different among treatments. Although late-phase respiration was not changed in soil containing cotton plant residues treated with elevated CO2, the increased production of biomass expected with atmospheric CO2 enrichment should add to the level of C stored in soils.

Technical Abstract: Increased atmospheric carbon dioxide (CO2) concentration will likely cause changes in plant growth and composition that might affect soil decomposition processes. The objective of this study was to test whether effects of CO2 enrichment in combination with nitrogen (N) fertility on tissue chemistry of cotton altered microbial decomposition rates measured in a laboratory incubation experiment. Cotton plants were exposed to two concentrations of CO2 (ambient and twice ambient) and two levels of N fertilization (sufficient and low) within greenhouse chambers for 8 wks. Leaf, stem and root tissue were assayed for total non-structural carbohydrates, lignin, proanthocyanidins, carbon (C) and N. Respiration rates of a sandy soil mixed with tissues from the various treatments were suppressed 16% by elevated CO2 and low N fertilization treatments during the early phase of decomposition. In general, treatment effects of elevated CO2 and low soil N fertility on tissue N concentration and C:N ratio were the most important factors affecting initial decomposition rates. Cumulative soil respiration after 44 d of incubation was not significantly different among treatments. Although late-phase respiration was not changed in soil containing cotton plant residues treated with elevated CO2, the increase production of biomass should add to the level of C stored in soils.

Last Modified: 10/23/2014
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