Rivka Fidel

Interests

Teaching

Soil science, environmental science, sustainable agriculture, and critical zone science

Research

Soil science, soil carbon, soil nitrogen, soil biogeochemistry, biochar, sustainable soil management, soil greenhouse gas emissions

Courses

Scholarly Contributions

Chapters

• Graber, E. R., Tsechansky, L., Fidel, R., Thompson, M. L., & Laird, D. A. (2017). Determining acidic groups at biochar surfaces via the Boehm titration. In Biochar: A Guide to Analytical Methods(pp 121-137). CSIRO.

Journals/Publications

• Hoglund, S. R., Rathke, S. J., Fidel, R. B., & Blankinship, J. C. (2023). Contrasting effects of biochar application rate in an alkaline desert cropland soil. Journal of Arid Environments, 215, 105011.
• Rahman, Z. U., Khan, H., Khan, B., Khalid, S., Humphrey, O. S., Fidel, R. B., Ahmad, S., & Ahmad, I. (2021). Faecal and nitrate contamination in the groundwater of Mardan district, Pakistan.. Environmental Geochemistry and Health, 1-10. doi:10.1007/s10653-021-00848-8
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  This study aimed to determine the status of groundwater contamination with faecal coliform and nitrate in the rural areas of Mardan district, Pakistan. Both analytes require regular monitoring according to the National Environmental Quality Standards (NEQS) of Pakistan. Groundwater samples (n = 100) were collected from 25 villages across four zones. Samples were analysed for physicochemical parameters including pH, electrical conductivity (EC), Escherichia coli (E. coli) contamination, nitrite, and nitrate ( $${\mathrm{NO}}_{2}^{ - }$$ and $${\mathrm{NO}}_{3}^{ - }$$ ). Whilst the average concentrations of $${\mathrm{NO}}_{3}^{ - }$$ in the water samples were within the permissible limits of 50 mg L−1 set by the World Health Organisation (WHO) and NEQS two villages exceeded the safety limits. Non-carcinogenic health risks of $${\mathrm{NO}}_{3}^{ - }$$ were estimated in terms of average daily dose (ADD) and hazard quotient (HQ). The HQ values for $${\mathrm{NO}}_{3}^{ - }$$ were > 1 for children signifying potential health risks; however, the adult population had HQ < 1 which indicates no risk. Groundwater samples tested positive for E. coli contamination in 13 villages, suggesting that residents may be living at risk of various microbial diseases due to drinking of contaminated water. The findings of this study provide valuable baseline data for groundwater researchers, policymakers, and the local public health department.
• Khan, A. Z., Ding, X., Khan, S., Ayaz, T., Fidel, R., & Khan, M. A. (2020). Biochar efficacy for reducing heavy metals uptake by Cilantro (Coriandrum sativum) and spinach (Spinaccia oleracea) to minimize human health risk. Chemosphere, 244. doi:https://doi.org/10.1016/j.chemosphere.2019.125543
• Fidel, R. B., David, L. A., & Timothy, P. B. (2019). Effect of Biochar on Soil Greenhouse Gas Emissions at the Laboratory and Field Scales. Soil Systems. doi:https://doi.org/10.3390/soilsystems3010008
• Bonin, C. L., Fidel, R. B., Banik, C., Laird, D. A., Mitchell, R., & Heaton, E. A. (2018). Perennial biomass crop establishment, community characteristics, and productivity in the upper US Midwest: Effects of cropping systems seed mixtures and biochar applications. EUROPEAN JOURNAL OF AGRONOMY, 101, 121-128.
• Fidel, R., Spokas, K. A., & Laird, D. A. (2018). Sorption of ammonium and nitrate to biochars is electrostatic and pH-dependent. Scientific Reports.
• Fidel, R. B., Laird, D. A., & Parkin, T. B. (2017). Impact of Biochar Organic and Inorganic Carbon on Soil CO2 and N2O Emissions. JOURNAL OF ENVIRONMENTAL QUALITY, 46(3), 505-513.
• Fidel, R. B., Laird, D. A., & Parkin, T. B. (2017). Impact of six lignocellulosic biochars on C and N dynamics of two contrasting soils. GLOBAL CHANGE BIOLOGY BIOENERGY, 9(7), 1279-1291.
• Fidel, R. B., Laird, D. A., Thompson, M. L., & Lawrinenko, M. (2017). Characterization and quantification of biochar alkalinity. CHEMOSPHERE, 167, 367-373.
• Fidel, R., Archontoulis, S., Babcock, B., Brown, R. C., Dokoohaki, H., Hayes, D., Laird, D. A., Miguez, F., & Wright, M. M. (2017). Commentary on "Current economic obstacles to biochar use in agriculture and climate change mitigation' regarding uncertainty, context-specificity and alternative value sources. CARBON MANAGEMENT, 8(2), 215-217.
• Fidel, R. B., Laird, D. A., & Thompson, M. L. (2013). Evaluation of Modified Boehm Titration Methods for Use with Biochars. JOURNAL OF ENVIRONMENTAL QUALITY, 42(6), 1771-1778.

Poster Presentations

• Fidel, R. (2019, July). Biochar carbon: can chemical lability predict biological lability?. US Biochar Initiative. Ft. Collins, CO.

Others

• Fidel, R. B. (2015, October). Biochar properties and impact on soil CO2 and N2O emissions. Iowa State University. https://dx.doi.org/10.31274/ETD-180810-4398
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  Doctoral dissertationAbstract:Biochar application to soil has been proposed as a means to sequester carbon and mitigate anthropogenic greenhouse gas (GHG) emissions. However, biochar directly influences soil GHG emissions in a complex-interactive manner that remains poorly understood, and hence further understanding of biochar-soil interactions is needed to evaluate biochar’s efficacy as a tool for greenhouse gas mitigation. The goals of this dissertation are to (1) quantify the organic and inorganic alkalis of several biochars, (2) quantify the impact of biochar properties on GHG emissions from diverse soils, and (3) identify mechanisms by which biochar properties influence GHG emissions from soils. To achieve these goals, biochar alkalis and thermochemical properties were analyzed, and three laboratory incubations as well as two field studies and one greenhouse study were conducted, employing eight biochars, two field sites, and four cropping systems. It was found that biochar properties are highly diverse, and effects on GHG emissions varied with respect to biochar properties and soil properties. Both carbonates and bicarbonate-extractable organic carbon in biochar contributed directly to very short term CO2 emissions but did not influence N2O emissions. Effects of biochar on N2O emissions were found to be more complex, with biochar increasing, decreasing or not affecting emissions depending on the context. Results highlight perturbation of N transformations, direct sorption of N, and enhanced water retention as potential mechanisms of biochar’s influence on N2O emissions and suggest that multiple mechanisms likely operate simultaneously.
• Fidel, R. B. (2012, August). Evaluation and implementation of methods for quantifying organic and inorganic components of biochar alkalinity. Iowa State University. https://www.proquest.com/openview/f176b3d271111c80ecfc1617b9d08473/1?pq-origsite=gscholar&cbl=18750
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  Master's ThesisStart of Abstract:When used as a soil amendment, biochar has the potential to increase soil pH and provide several other benefits to soil quality, but scientific understanding of the mechanisms by which biochar influences the acid-base chemistry of soil is incomplete. Integral to this understanding is knowledge of the components of biochar alkalinity. However, methods for quantifying the components of biochar alkalinity vary greatly among biochar studies. Components of biochar alkalinity have been shown to include organic functional groups, carbonates, and other inorganic alkalis. Unfortunately, studies quantifying all three of these components are lacking, and of the studies that quantify at least one component, different methods are used from study to study. One method of particular concern is the Boehm titration, which was originally developed for quantifying reactive organic functional groups of carbon blacks and activated …