Aerobic composting with hydrothermal carbonization aqueous phase conditioning: Stabilized active gaseous nitrogen emissions.

The losses of reactive gaseous nitrogen (N), including ammonia (NH) and nitrous oxide (NO), represent a pressing environmental issue during composting. However, the impact of hydrothermal carbonization aqueous phase (HAP) on compost gaseous N emissions and the underlying mechanisms remain largely unexplored. Herein, Quercus acutissima leaves-derived HAP and its modified HAP (MHAP) were added to the chicken manure compost at 5 % (w/w) and 10 % (w/w) applied rates to observe changes in NH and NO fluxes, compost properties and bacterial communities.

Manure-derived hydrochar superior to manure: Reducing non-point pollution risk by altering nitrogen and phosphorus fugacity in the soil-water system.

Hydrothermal carbonization (HTC) technology is an emerging technology for the disposal of manure-based wet wastes. However, the effects of manure-derived hydrochar inputs to agricultural soils on nitrogen (N) and phosphorus (P) morphology and conversion in soil-water systems remain largely unexplored. In this study, pig and cattle manure (PM and CM), and their derived hydrochar (PCs and CCs) were applied to agricultural soils, with changes in nutrient morphology and enzyme activities related to N and P transformation in the soil-water systems observed through flooded incubation experiments.

Hydrochar amendments stimulate soil nitrous oxide emission by increasing production of hydroxyl radicals and shifting nitrogen functional genes in the short term: A culture experiment.

The application of waste biomass-derived hydrochar to soil may cause extremely intensive nitrous oxide (NO) fluxes that can challenge our current mechanistic understanding of the global nitrogen cycle in the biosphere. In this study, two waste biomasses were used to prepare cyanobacterial biomas-derived hydrochar (CHC) and wheat straw-derived hydrochar (SHC) for short-term incubation experiments to identify their effects and mechanisms of waste biomass-derived hydrochar on soil NO efflux, with time-series samples collected for NO efflux and soil analysis. The results showed that CHC and SHC caused short-term bursts of NO effluxes without nitrogen inputs.

How does biochar aging affect NH volatilization and GHGs emissions from agricultural soils?

Biochar has been considered as a potential tool to mitigate soil ammonia (NH) volatilization and greenhouse gases (GHGs) emissions in recent years. However, the aging effect of biochar on soils remains elusive, which introduces uncertainty on the effectiveness of biochar to mitigate global warming in a long term. Here, a meta-analysis of 22 published works of literature with 217 observations was conducted to systematically explore the aging effect of biochar on soil NH and GHGs emissions.