施用不同污泥堆肥品对土壤温室气体排放的影响

通过田间试验，分别施加两种不同的污泥堆肥品（A：含生物质炭堆肥品，B：不含生物质炭堆肥品）和不同施肥量，分析土壤CO₂、CH₄和N₂O动态变化特征和排放系数，研究施用污泥堆肥品对土壤温室气体排放的影响.结果表明，土壤CO₂和CH₄排放主要集中在生长期，生物质炭堆肥品低施用量能减少CO₂排放，而高施肥量增加CO₂排放.CH₄排放主要为负值，总体表现为土壤吸收CH₄，对照处理吸收量远高于其他处理（P<0.01），A组处理CH₄吸收量随施肥量的增加而增加（P<0.05）.N₂O排放集中在发芽期和幼苗期，施肥量越高，排放量越大（P<0.01）.污泥堆肥品农用过程排放的温室气体主要是N₂O，施用A、B两种污泥堆肥品的土壤N₂O排放系数分别为1.02%~1.90%和1.28%~2.93%.生物质炭堆肥品具有显著的碳减排效果，其温室气体排放量比不含生物质炭堆肥品的土壤低19.49%~35.56%，且对于N₂O的减排效果较CH₄更为显著.

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 CO₂, CH₄ and N₂O 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 CO₂ and CH₄ mainly occurred in the plant growth period with low fertilizer amount of biomass charcoal compost reducing CO₂ emissions, and high application content increasing CO₂ emissions. CH₄ emission fluxes showed negative values, indicating that soil could adsorb CH₄, 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). N₂O emissions mainly occurred at the germination and seedling stages, and emission fluxes increased with the fertilizing amount (P<0.01). N₂O 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 N₂O emission reduction (compared with CH₄ mitigation).