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Biochar application increases sorption of nitrification inhibitor 3,4-dimethylpyrazole phosphate in soil

Keiblinger, KatharinaM., Zehetner, Franz, Mentler, Axel, Zechmeister-Boltenstern, Sophie
Environmental science and pollution research international 2018 v.25 no.11 pp. 11173-11177
agricultural land, ammonium, biochar, climate change, emissions, feedstocks, hydrophobicity, models, nitrates, nitrification inhibitors, nitrous oxide, nutrient use efficiency, oxidation, phosphates, pyrolysis, soil, soil fertility, sorption, temperature
Biochar (BC) application to soils is of growing interest as a strategy to improve soil fertility and mitigate climate change. However, BC-induced alterations in the soil N cycle are currently under debate. BC has recently been shown to accelerate the emissions of N₂O via the biotic ammonium oxidation pathway, which results in lower nitrogen use efficiency and environmentally harmful losses of NO₃ and/ or N₂O. To avoid these potential losses, the use of nitrification inhibitor (NI) could provide a useful mitigation strategy for BC-amended agricultural fields. Here, we tested the sorption behavior of a model NI, the synthetic 3,4-dimethylpyrazole phosphate (DMPP) on 15-month-aged soil-BC mixtures. We saw that BC additions increased DMPP sorption to varying extents depending on BC feedstock type and pyrolysis temperature. The highest sorption was found for BC pyrolyzed at a lower temperature. BC effects on soil physico-chemical characteristics (i.e., hydrophobicity) seem to be important factors.