Biochar and Manure from Cattle Fed Biochar as Agricultural Amendments Alter CH4 Oxidation in a Gray Luvisol

Abstract

Greenhouse gases (GHG) emissions from agricultural practices contribute 14% of anthropogenic emissions to the atmosphere, and novel practices to reduce these emissions, including feeding cattle a modified diet, are of interest. This study examines how additions of manure from cattle fed a regular diet or a diet supplemented with 2% biochar, and biochar at 5 or 10 Mg ha−1, impact GHG emissions in a Gray Luvisol agricultural field experiment. Emissions of CH4 and N2O were monitored, and soil samples were collected to analyze exchangeable NPKS, microbial biomass, total C and N, electrical conductivity, and pH. Wheat (Triticum aestivum) was planted, and grain yield measured. We calculated the yield-based emission factor (EFyield) and cumulative area-based GHG emissions emission factor (EFarea). The results showed an up to 98.5% change in the inhibition of CH4 oxidation from biochar-manure + biochar at 5 and 10 Mg ha−1 compared to the CT. The biochar in biochar-manure may have acted as a biocide to methanotrophs, causing a reduction in the release of CH4 over time. Yet, there were no significant differences in N2O emissions amongst treatments. Therefore, biochar-manure + biochar at 5 and 10 Mg ha−1 applications may impact total GHG emissions and improve grain productivity and protein content compared to BM alone.