Is biochar-manure co-compost a better solution for soil health improvement and N2O emissions mitigation?. (October 2017)

• Record Type: Journal Article
• Authors: Yuan, Yinghong; Chen, Huaihai; Yuan, Wenqiao; Williams, David; Walker, John T.; Shi, Wei
• Is Part Of: Soil biology and biochemistry. Volume 113(2017)
• Page Start: 14
• Page End: 25
• Publication Date: 2017-10
• Subjects: Biochar -- Compost -- Nitrous oxide -- 15N site-preference -- Enzyme activity -- Bacterial denitrifier; Soil biochemistry -- Periodicals; Soil biology -- Periodicals; Sols -- Biochimie -- Périodiques; Sols -- Biologie -- Périodiques; Sols -- Microbiologie -- Périodiques; Bodembiologie; Biochemie; 631.46
• DOI: 10.1016/j.soilbio.2017.05.025
• Languages: English
• ISSNs: 0038-0717

Abstract

Abstract: Land application of compost has been a promising remediation strategy for soil health and environmental quality, but substantial emissions of greenhouse gases, especially N2 O, need to be controlled during making and using compost of high N-load wastes, such as chicken manure. 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-chicken manure co-compost (BM) and chicken manure compost (M) on soil biological properties and processes in a 120-d microcosm experiment at the soil moisture of 60% water-filled pore space. Our results showed that BM and M addition significantly enhanced soil total C and N, inorganic and KCl-extractable organic N, microbial biomass C and N, cellulase enzyme activity, abundance of N2 O-producing bacteria and fungi, and gas emissions of N2 O and CO2 . However, compared to the M treatment, BM significantly reduced soil CO2 and N2 O emissions by 35% and 27%, respectively, over the experimental period. The 15 N-N2 O site preference, i.e., difference between 15 N-N2 O in the center position (δ 15 N α ) and the end position (δ 15 N β ), was ∼17‰ for M and ∼26‰ for BM during the first week of incubation, suggesting that BM suppressed N2 O from bacterial denitrification and/or nitrifier denitrification. This inference was well aligned with the observation that soil glucosaminidase activity and nirK gene abundance were lower in BM than M treatment. Further, soil peroxidase activity was greater in BM than M treatment, implying soil organic C was more stable in BM treatment. Our data demonstrated that the biochar-chicken manure co-compost could substantially reduce soil N2 O emissions compared to chicken manure compost, via controls on soil organic C stabilization and the activities of microbial functional groups, especially bacterial denitrifiers. Highlights: Impacts of biochar-manure (BM) compost on soil N processes were studied. BM significantly reduced soil CO2 and N2 O emissions compared to manure compost. 15 N-N2 O site preference suggested N2 O reduction from bacterial denitrification. This correlated to lower nirK gene abundance but higher peroxidase activity in BM.