Cattle Manure Biochar could Reduce Earthworm Greenhouse Gas Emissions in Forest Soil

Soil, particularly agricultural & forest soils, is responsible for approximately 20% and 62 % of global carbon dioxide (CO2) and nitrous oxide (N2O) emissions, respectively. As a result, it is critical to investigate long-term management strategies for reducing soil CO2 and N2O emissions.

Soil fauna, particularly earthworms, can have a significant impact on soil biogeochemical processes and greenhouse gas emissions. In addition, raising beef cattle produces a large amount of cow manure, which, if not properly handled, pollutes surface and groundwater and emits large amounts of greenhouse gases during storage and processing.

Pyrolysis can be used to convert cow manure into biochar, which can be used to remove pollutants and improve soil fertility. Soil amendment with cow manure biochar can reduce greenhouse gas emissions while also improving soil quality.

The amount of biochar added had an impact on earthworm activity, which in turn had an impact on soil CO2 and N2O emissions. One of the most common earthworm species in North America is Aporrectodea turgida. However, little is known about this earthworm's contribution to CO2 and N2O fluxes in agricultural and forest soils, as well as its interaction with biochar.

Through an incubation experiment, a team of researchers from the University of Alberta, Beijing Forestry University, and Tsinghua University investigated the effects of cow manure biochar and earthworms on soil CO2 and N2O emissions, as well as soil physicochemical properties. Frontiers of Environmental Science & Engineering published the findings.

They discovered that adding cow manure biochar to agricultural soil increased CO2 and N2O emissions while reducing CO2 and N2O emissions in forest soil. CO2 and N2O emissions from both soils were also aided by earthworms. Earthworm activity in the forest soil could be offset by adding 10% cattle manure biochar, which would reduce CO2 and N2O emissions as well as NO3-N and DON concentrations.

The activities of earthworms, such as respiration, burrowing, feeding, and excretion, not only affect soil physical structure (e.g., improved aeration) but also promote microbial activity, which results in increased CO2 and N2O emissions. It also has a significant impact on the pH of forest soil.

While biochar increases the activity of N2O reductase within denitrifying soil microbial and promotes soil nitrification and denitrification, it has an impact on CO2 and NO2 emissions. Furthermore, the interaction of cattle manure biochar with earthworms has a significant impact on soil NH4+-N levels.

As a result, high rates of manure biochar application, as suggested by the researchers, should be a viable management option for reducing CO2 and N2O emissions and improving soil biochemical properties in forest soil.

(Source: Phys.org)