[Effect of Application of Sewage Sludge Composts on Greenhouse Gas Emissions in Soil].

Effect of application of sewage sludge compost on the emission of greenhouse gas from soil was investigated by analyzing the dynamic characteristics and emission factor of CO ₂ , CH ₄ and N ₂ O in soil after spiking two different composts (A:compost with biochar, B:compost without biochar) with varying fertilizing amount into soil. The results indicated that emissions of CO ₂ and CH ₄ mainly occurred in the plant growth period with low fertilizer amount of biomass charcoal compost reducing CO ₂ emissions, and high application content increasing CO ₂ emissions. CH ₄ emission fluxes showed negative values, indicating that soil could adsorb CH ₄ , and the adsorbing amount for control was significantly higher than those for other treatments ( P <0.01). The absorbing amount in treatment A increased with the fertilizing amount ( P <0.05). N ₂ O emissions mainly occurred at the germination and seedling stages, and emission fluxes increased with the fertilizing amount ( P <0.01). N ₂ O was considered as the main generated greenhouse gas during agricultural process with sludge compost, and its emission factor from sludge compost soil was 1.02%-1.90% (A compost) and 1.28%-2.93% (B compost), respectively. Biochar could significantly reduce the carbon emission, as the total greenhouse gas released from soil with biochar compost was 19.49% to 35.56% less than that in soil without biochar, which was more obvious for N ₂ O emission reduction (compared with CH ₄ mitigation).