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Your search keyword '"Guber, Andrey K."' showing total 36 results
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36 results on '"Guber, Andrey K."'

21. Effect of bovine manure on fecal coliform attachment to soil and soil particles of different sizes

Author

Guber, Andrey K., Pachepsky, Yakov A., Shelton, Daniel R., and Olivia Yu

Subjects
Soil microbiology -- Research, Bacteria, Pathogenic -- Physiological aspects, Bacteria, Pathogenic -- Food and nutrition, Biological sciences
Abstract

Research study is conducted to compare the attachment of fecal coliforms to different soils and soil fractions and to assess the effect of bovine manure on fecal coliform attachment to soil and soil functions. It is found that the attachment to the coated sand particle is similar to the attachment to silt and clay.

Published
2007

22. X‐ray computed tomography to predict soil N2O production via bacterial denitrification and N2O emission in contrasting bioenergy cropping systems.

Author

Kravchenko, Alexandra N., Guber, Andrey K., Quigley, Michelle Y., Koestel, John, Gandhi, Hasand, and Ostrom, Nathaniel E.

Subjects
*DENITRIFICATION, *ORGANIC compounds, *PLANT diversity, *CARBON in soils, *SOIL moisture
Abstract

While renewable biofuels can reduce negative effects of fossil fuel energy consumption, the magnitude of their benefits depends on the magnitude of N2O emissions. High variability of N2O emissions overpowers efforts to curb uncertainties in estimating N2O fluxes from biofuel systems. In this study, we explored (a) N2O production via bacterial denitrification and (b) N2O emissions from soils under several contrasting bioenergy cropping systems, with specific focus on explaining N2O variations by accounting for soil pore characteristics. Intact soil samples were collected after 9 years of implementing five biofuel systems: continuous corn with and without winter cover crop, monoculture switchgrass, poplars, and early‐successional vegetation. After incubation, N2O emissions were measured and bacterial denitrification was determined based on the site‐preference method. Soil pore characteristics were quantified using X‐ray computed microtomography. Three bioenergy systems with low plant diversity, that is, corn and switchgrass systems, had low porosities, low organic carbon contents, and large volumes of poorly aerated soil. In these systems, greater volumes of poorly aerated soil were associated with greater bacterial denitrification, which in turn was associated with greater N2O emissions (R2 = 0.52, p < 0.05). However, the two systems with high plant diversity, that is, poplars and early‐successional vegetation, over the 9 years of implementation had developed higher porosities and organic carbon contents. In these systems, volumes of poorly aerated soil were positively associated with N2O emissions without a concomitant increase in bacterial denitrification. Our results suggest that changes in soil pore architecture generated by long‐term implementation of contrasting bioenergy systems may affect the pathways of N2O production, thus, change associations between N2O emissions and other soil properties. Plant diversity appears as one of the factors determining which microscale soil characteristics will influence the amounts of N2O emitted into the atmosphere and, thus, which can be used as effective empirical predictors. Long‐term implementation of bioenergy systems with contrasting plant diversity influences microscale pore architecture, which then affects predictors of N2O production and emission. [ABSTRACT FROM AUTHOR]

Published
2018
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