添加硝化抑制剂、秸秆及生物炭对亚热带农田土壤N2O排放的影响

为了筛选适合亚热带农田土壤性质和气候条件的N_2O减排调控措施,采用室内培养试验研究了添加硝化抑制剂、秸秆和生物炭三种调控措施对亚热带红壤(JX)和紫色土(SC)农田土壤N_2O排放的影响。结果表明,在添加硝化抑制剂(三氯甲基吡啶)的初期阶段(24 h),可显著降低两种土壤N_2O的排放,尤其是SC土壤,抑制程度可达62%。而生物炭的添加可显著增加JX土壤的N_2O排放,但在SC土壤中虽有升高趋势却不显著。添加秸秆对土壤N_2O排放的影响与秸秆类型和性质、土壤质地和理化性质,以及添加的时长有关。短时条件内(24 h),苜蓿和水稻秸秆可显著增加SC土壤N_2O排放,而添加甘蔗渣后N_2O排放虽有增加但不显著;JX土壤中添加水稻秸秆可显著刺激N_2O排放,但苜蓿和甘蔗渣则显著降低了其排放。添加秸秆较长时间后,苜蓿和水稻秸秆对土壤N_2O排放的影响程度下降,而甘蔗渣在6个月后仍能显著降低SC土壤N_2O的排放。研究表明,在对土壤进行调控时,若以减少N_2O排放为目的,应当根据土壤类型和性质选择合适的措施。

Effects of nitrification inhibitor, crop residues, and biochar applications on N2O emissions by subtropical agricultural soils

The effects of a nitrification inhibitor(nitrapyrin), crop residues, and rice straw-derived biochar applications on N₂O emissions by an acidic agricultural soil from Jiangxi Province(JX) and an alkaline agricultural soil from Sichuan Province(SC) were investigated using a laboratory incubation experiment. The results showed that nitrapyrin significantly reduced N₂O emissions in both soils during the first stage(24 h) after addition, especially in the SC soil where the N₂O emission was reduced by 62%. Biochar application significantly enhanced N₂O emission in the JX soil, but its effects in the SC soil were not significant. In contrast, the effects of crop residue incorporation on soil N₂O emissions depended on the type and characteristics of the crop residues, the physicochemical properties of the soil, and how long the residues had been incorporated into the soil. Over the short term(24 h), alfalfa and rice straw significantly enhanced N₂O emissions, whereas bagasse addition did not lead to any significant increases in N₂O emissions from the SC soil. The N₂O emissions in the JX soil were significantly enhanced by rice straw application, but significantly inhibited by alfalfa and bagasse applications. Increasing the duration of incorporation weakened the effects of alfalfa and rice straw on N₂O emissions, whereas the inhibition effect of bagasse on N₂O emissions could be maintained for 6 months. Overall, these results highlight the necessity to connect N₂O mitigation strategies with soil types and properties when attempting to reduce N₂O emissions.