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Title: SOIL OF THE INTENSIVE AGRICULTURE BIOME OF BIOSPHERE 2

Author
item Torbert, Henry - Allen
item Johnson, Hyrum

Submitted to: Journal of Soil and Water Conservation Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/2001
Publication Date: 1/15/2002
Citation: Torbert, H.A., Johnson, H.B. Soil of the intensive agriculture biome of Biosphere 2. Journal of Soil and Water Conservation Society. 2000. v. 56. p. 4-11.

Interpretive Summary: The Biosphere 2 is an unique facility which encloses 1.28 ha of synthetic communities (biomes) of plants and soils in a glass and metal shell, which which is being utilized for research in global change. Previous utilization of this facility resulted in excessively high atmospheric CO2 concentrations and O2 depletion. The objective of this study was to to examine the soil of the intensive agriculture biome (IAB) to both determine the effect of the previously elevated atmospheric CO2 concentration on soil processes and to determine the soil's suitability for continued global change research experimentation. In 1996, a series of soil samples from four soil depth increments were collected and analyzed from the IAB, including analysis of organic C, total N and P, C:N ratio, and dell C**13 as well as extractable lmicro and macro soil nutrients. These samples were compared to archieved soil and plant samples collected during the initial closure of the Biosphere 2 facility. When averaged across plots in each experimental bay, no significant differences were observed in soil organic C, total N and P, and C:N ratio. However, differences were found between soil nitrate and other extractable plant nutrients, indicating that careful attention will need to be paid to baseline soil nutrient data when interpreting future research. Examination of the data for global change effects on soil processes in the IAB indicated that the management systems may be a dominate factor in potential soil C sequestration, and that soil organic C content may be modified with elevated CO2 due to changes in plant biomass, which could result in increased C sequestration in soil.

Technical Abstract: The Biosphere 2 is an unique facility which encloses 1.28 ha of synthetic communities (biomes) of plants and soils in a glass and metal shell, which is being utilized for research in global change. Previous utilization of this facility resulted in excessively high atmospheric CO2 concentrations and O2 depletion. The objective of this study was to examine the soil of the intensive agriculture biome (IAB) to both determine the effect of the previously elevated atmospheric CO2 CO2 concentration on soil processes and to determine the soil's suitability for continued global change research experimentation. In 1996, a series of soil samples from four soil depth increments were collected and analyzed from the IAB, including analysis of organic C, total N and P, C:N ratio, and dell C**13 as well as extractable micro and macro soil nutrients. These samples were compraed to archived soil and plant samples collected during the initial closure of the Biosphere 2 facility. When averaged across plots in each experimental bay, no significant differences were observed in soil organic C, total N and P, and C:N ratio. However, differences were found between soil nitrate and other extractable plant nutrients, indicating that careful attention will need to be paid to baseline soil nutrient data when interpreting future research. Examination of the data for global change effects on soil processes in the IAB indicated that the management systems may be a dominate factor in potential soil C sequestration, and that soil organic C content may be modified with elevated CO2 due to changes in plant biomass, which could result in increased C sequestration in soil.