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Is biochar-manure co-compost a better solution for soil health improvement and N2O emissions mitigation?
Citation:
Yuan, Y., H. Chen, W. Yuan, D. Williams, J. Walker, AND w. Shi. Is biochar-manure co-compost a better solution for soil health improvement and N2O emissions mitigation? BIOGEOCHEMISTRY. Springer, New York, NY, 113:14-25, (2017).
Impact/Purpose:
Composting, a waste treatment technology, transforms organic material into stabilized compost, which can provide numerous benefits to soil fertility/quality and thus agricultural productivity (Chadwick et al., 2011; Chan et al., 2007; Lehmann et al., 2006). Land application of compost often enlarges the content of soil organic matter, promotes the formation of soil aggregates, and increases the availability of soil nutrients (Bacilio et al., 2003; Stamatiadis et al., 1999). It can also increase soil microbial biomass and the activity of enzymes involved in nutrient mobilization (Bedada et al., 2014; Hernández et al., 2014). Compost has been found to be as effective as synthetic fertilizers in supplying nutrients to crops and thus improving grain yields; yet, it is more cost-effective and environmentally-friendly (Ahmad et al., 2007; Leite et al., 2010).
Description:
Land application of compost has been a promising remediation strategy for soil health and environmental quality, but substantial emissions of greenhouse gases, especially N2O, need to be controlled during making and using compost. Biochar as a bulking agent for composting has been proposed as a novel approach to solve this issue, due to large surface area and porosity, and thus high ion exchange and adsorption capacity. Here, we compared the impacts of biochar-manure co-compost (BM) and manure compost (M) on soil biological properties and processes in a microcosm experiment. Our results showed that BM and M addition significantly enhanced soil total C and N, inorganic and organic N, microbial biomass C and N, cellulase enzyme activity, abundance of N2O-producing bacteria and fungi, and gas emissions of N2O and CO2. However, compared to the M treatment, BM significantly reduced soil CO2 and N2O emissions by 35% and 27%, respectively, over the experimental period. The 15N-N2O site preference was ~ 17‰ for M and ~ 27‰ for BM, suggesting that BM suppressed N2O from bacterial denitrification and nitrifier denitrification. Soil glucosaminidase activity and nirK gene abundance were lower in BM than M treatments. However, soil peroxidase activity and the abundance of ammonium oxidizing archaea were greater in BM than M treatments. Our data demonstrated that biochar-manure co-compost could substantially reduce soil N2O emissions from manure compost via controls on soil organic C stabilization and the activities of microbial functional groups, especially bacterial denitrifiers.
