Animal manure has been increasingly adopted as a more sustainable substitute for synthetic fertilizers but might result in increased dissolved organic C (DOC) and phosphate (PO ) leaching and elevated greenhouse gas emissions from soil. Biochar may reduce nutrient loss from manure-amended soils, but large-scale application has been hindered, in part, by its high cost. Minimum cost alternatives, such as incomplete coal combustion residue (char), may provide a more viable option to farmers, but char needs to be analyzed in comparison to high-temperature pine biochar before recommendations can be made. We valuated losses of soil C, N, and P, as well as plant yields and changes in microbial biomass, in two contrasting soils amended with dairy slurry or swine lagoon wastewater and with biochar or coal char over 105 d. Dissolved organic C leaching decreased with addition of biochar or char (0.6-27% or 1.6-36%), independent of soil texture and manure type. Leaching of PO was reduced by biochar (15-24%) and char (38-50%) in the silt loam. Soil N leaching increased after char application (likely due to our high application rate) but was unaffected by biochar. Char reduced CO emissions from the sandy loam by 9.7-54%, whereas both biochar and char increased CO emissions in the silt loam by 38-48% during plant root senescence. Depending on soil characteristics, char may outcompete biochar with respect to reduction of PO and DOC leaching. Unlike biochar, some char-N is available, and this should be accounted for when considering application rates.
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http://dx.doi.org/10.1002/jeq2.20327 | DOI Listing |
Environ Sci Technol
January 2025
Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States.
The electrochemical properties of chars have been recently described, positioning chars as active participants in microbial redox processes through functional groups, aromatic structures, redox-active metals, and radicals. While bench-scale studies have advanced mechanistic understanding of char's behavior and potential effects, translating these findings to complex ecosystems remains challenging. This is mainly due to the complexities of microbial communities and the unique properties of various ecosystems.
View Article and Find Full Text PDFJ Environ Manage
December 2024
Key Laboratory of Energy Thermal Conversion and Control, Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, 210096, PR China.
Bioresour Bioprocess
December 2024
Production Systems Unit, Grasslands and Sustainable Agriculture Group, Natural Resources Institute Finland (Luke), Maaninka, FI-71750, Finland.
Thermal processes are emerging as promising solutions to recovering phosphorus and other nutrient elements from anaerobic digestates. The feasibility of nutrient element recovery depends largely on the fates of nutrient elements and heavy metals during thermal processing. This study assesses the partitioning of macronutrients (N, P, K, Na, Ca and Mg) and heavy metals (Zn, Cu, and Mn) between condensed and gaseous phases during thermal conversion of cattle slurry digestates in gas atmospheres of pyrolysis, combustion, and gasification processes.
View Article and Find Full Text PDFJ Hazard Mater
November 2024
Energy and Resources Institute, Charles Darwin University, Ellengowan Drive, Purple 12.01.08, Casuarina, NT 0810, Australia. Electronic address:
Contamination of chars with dioxin-like polychlorinated biphenyls (dl-PCB) significantly limits their use and hinders their deployment in the circular bioeconomy, specifically in applications that may lead to dietary exposure. Here, for the first time, we review the levels of contamination of chars produced from pyrolysis and hydrothermal carbonisation (HTC) with dl-PCB congeners. We conduct a detailed and critical examination of the role played by the processing parameters, such as temperature and residence time, and the reaction mechanisms, to detoxify the biomass under an oxygen-free atmosphere during its valorisation.
View Article and Find Full Text PDFJ Environ Manage
December 2024
Biological Systems Engineering, Washington State University, Pullman, WA, 99163, USA. Electronic address:
Land application of dairy manure is the most common practice for disposal of this waste. Agricultural fields surrounding concentrated animal feeding operations (CAFOs) often have high levels of N and P because of manure over-application. However, its low bulk density limits the amount of manure that can be profitably transported for use as fuel or fertilizer.
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