长效碳酸氢铵对土壤硝化-反硝化过程和NO与N2O排放的影响

室内实验(25℃和50%WFPS)比较研究了碳酸氢铵(普碳)和长效碳酸氢铵(长碳)对粘质土壤(粘土)和壤质土壤(壤土)硝化反硝化过程和NO与N₂O排放的影响.长碳中的DCD在粘土中的硝化抑制作用很弱,在壤土中显著,与普碳处理相比,NH₄⁺持续时间分别延长7d和33d.15d内,施普碳(100μgN·g^-1)情况下,粘土和壤土NO排放量分别占施N量的0.60%和1.06%,分别是相应土壤N₂O排放量的30和12倍.施长碳后,粘土和壤土NO排放量分别减少67%和95%,N₂O排放量分别减少64%和55%.有氧培养39d后,外加硝酸盐(200μgKNO₃-N·g^-1),接着淹水厌氧培养7d,壤土长碳处理较普碳处理反硝化总损失减少50%,但N₂O排放量增加113%.

Effect of modified ammonium bicarbonate on nitrification-denitrification process and NO and N2O emission

Compared with ammonium bicarbonate(AB),the effect of modified ammonium bicarbonate (MAB) on nitrification and denitrification processes and NO and N₂O emissions in a clay soil (C soil) and a loam soil (L soil) was studied in laboratory (25℃ and 50% WFPS).The inhibition effect of DCD from MAB on nitrification was relatively small in C soil,but considerably great in L soil.Compared with AB,MAB extended 7 days and 33 days for retaining NH₄⁺.During 15 days,the NO emission from C soil and L soil respectively accounted for 0.60% and 1.06% of applied N under AB application (100μg N·g^-1 ),which were as 30 and 12 times as the N₂O emission from corresponding soils.After applying MAB,the emission of NO from C soil and L soil decreased by 67% and 95%,and the emission of N₂O decreased by 64% and 95%,respectively.After 39 days of aerobic incubation,then anaerobically flooded incubation with nitrate addition (200μg KNO₃-N·g^-1 ) for 7 days,the total loss of denitrification in MAB in L soil was 50% less,and N₂O emission was 113% more than in AB in same soil.