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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Soil, Water & Air Resources Research » Research » Publications at this Location » Publication #365944

Research Project: Managing Energy and Carbon Fluxes to Optimize Agroecosystem Productivity and Resilience

Location: Soil, Water & Air Resources Research

Title: Soil carbon dioxide emissions in a sorghum field: Row position and growth stage effects

item KUANG, XIANYAN - Alabama A & M University
item XIAO, RONG - Alabama A & M University
item XIAO, XINHUA - Alabama A & M University
item YUAN, QUNYING - Alabama A & M University
item Sauer, Thomas - Tom
item DAVIS, DEDRICK - Alabama A & M University

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2020
Publication Date: 2/8/2021
Citation: Kuang, X., Xiao, R., Xiao, X., Yuan, Q., Sauer, T.J., Davis, D. 2021. Soil carbon dioxide emissions in a sorghum field: Row position and growth stage effects. Agrosystems, Geosciences & Environment. 4(1). Article e20138.

Interpretive Summary: Carbon dioxide (CO2) emissions from the soil indicate how fast organic matter is decomposing and how soil and crop management affect the decomposition rate. In this study, soil CO2 emissions were measured at different distances from the crop row in two types of sorghum grown in north Alabama. The results showed that CO2 emissions change by time of year and positions for grain sorghum but differences among position were not as large for biomass sorghum. These results suggest that CO2 from the crop roots contributed more to CO2 emissions from the biomass sorghum crop which is larger and thought to have a larger root system. These results are of interest to growers and scientists interested in increasing soil organic matter as the choice of crop and measurement location are important factors to consider when evaluating a potential cropping system.

Technical Abstract: Soil CO2 emission (SCE) as a soil health indicator is known to be impacted by multiple factors, yet few reports exist on whether and how row position and growth stage affect SCE especially in the context of different crop types. Sorghum is an ideal row crop candidate in the Southeast U.S., with both grain sorghum and biomass sorghum being two common types grown. The objective of this study was to monitor SCE dynamics in a field grown with grain sorghum and biomass sorghum in northern Alabama and to examine the effects of row position and growth stage on SCE. SCEs were measured (bi-) weekly using a closed chamber survey system during the entire growth period. The results showed that SCE increased steadily during the vegetative stage and then declined afterwards until maturity for both sorghum types. Significant differences in SCE were observed between row positions, with in-row SCE greater than inter-row SCE during the entire growing season under grain sorghum production. Such a difference occurred only during the vegetative stage under biomass sorghum production. Additionally, a significantly higher response of SCE to soil temperature during the vegetative stage was observed under biomass sorghum production but this pattern did not exist under grain sorghum production. SCE in this study was affected by row position and growth stage differently for the sorghum crop types. It is speculated that these observations might be attributed to the different spatiotemporal dynamics of roots as a composite source of SCE during sorghum growth and development. This study provides/adds evidence that SCE can be affected by multiple factors including row position, growth stage, and crop type in addition to soil temperature and moisture. This study has implications for SCE estimation techniques that should not be oversimplified but need to take row position and growth stage into consideration.