城市污泥堆肥对土壤温室气体排放的短期影响

采用田间试验，施用2种城市污泥堆肥（含生物质炭和不含生物质炭），通过静态暗箱-气相色谱法研究污泥堆肥土地利用过程温室气体排放特征，探讨施用污泥堆肥的短期影响作用.结果表明，在观测时间内，N₂O排放主要集中在前3周，约占总排放量的87.9%~95.6%.N₂O排放量均随污泥堆肥施用量的增加而增加（P<0.05），裸地N₂O排放量高于种植作物处理.施用含生物质炭污泥堆肥能减少土壤N₂O排放，且随着施用量的增加，N₂O减少量越大（P<0.05）.CH₄排放量较低，在试验前期和后期主要为负，总体表现为吸收CH₄.各处理吸收CH₄主要集中在第18d以后，其CH₄吸收量占总吸收量的52.1%~66.7%.施用含生物质炭污泥堆肥处理CH₄吸收量比不含生物质炭污泥堆肥处理低35.2%~62.2%，同时，裸地CH₄吸收量明显高于种植作物处理（P<0.05）.CO₂排放也主要集中在18d以后，约占排放总量的50.5%~61.8%.种植作物能促进CO₂的排放，种植作物处理是裸地的1.34~1.57倍.在观测时间内，污泥堆肥土地利用是CH₄的弱吸收汇，是N₂O和CO₂的排放源，施加污泥堆肥能显著增加土壤N₂O和CO₂的排放.施用生物质炭污泥堆肥短期内能够减少温室气体总排放量，温室气体减排量达到20.41%~62.51%.

Short-term effects of sewage sludge compost application on emissions of greenhouse gases from soil

Two different sewage sludge composting products (with and without biochar) were applied in field to study short-term impacts of their application on the greenhouse gases (CH₄, CO₂ and N₂O) emission from soil. The results indicated that N₂O emissions mainly occurred in the first three weeks, with the emission amount accounting for 87.9%~95.6% of the total emissions during the observation period. The emission amount of N₂O increased with the application amount of compost (P<0.05), and N₂O emission from bare land was higher than that of crop plants treatment. The application of sludge composting can lead to the reduction of the N₂O emissions from soil, and the N₂O reduction amount increased with the increase of the fertilizing amount (P<0.05). CH₄ emission fluxes showed negative values in the early and late stages of the experiment, indicating that soil could adsorb CH₄. The absorption of CH₄ took place mainly after 18 days, accounting for 52.1%~66.7% of the total absorping amounts. The absorping amount of CH₄ in soil with biochar compost was 35.2% to 62.2% less than that in soil without biochar, and higher absorping amount of CH₄ appeared in bare land when compared with the land with planting crops (P<0.05). CO₂ emissions mainly occurred after 18days, accounting for 50.5%~61.8% of the total emission. The planting crops can promote the CO₂ emission in soil, which was 1.34~1.57 times that of the bare land. Thus, it can be speculated that land application of compost was a weak sink of CH₄ and a source of N₂O and CO₂ emissions during the observation period. The application of sludge composting can lead to the increase of the emissions of N₂O and CO₂ in soil. Sludge compost with biochar in short-term could reduce the N₂O and CO₂ emissions from soil, and the biochar played an important role in reducing the greenhouse gas emissions, as the emission amounts from soil with biochar compost was 20.41% to 62.51% less than that in soil without biochar.