不同种类氮肥对土壤释放N2O的影响

用培养试验模拟研究了在正常水分 ( 2 2 % )、干旱 ( 1 2 % )和高含水量 ( 32 % )条件下 ,普通碳酸氢铵 (普碳 )、尿素及新型肥料长效碳酸氢铵 (长碳 )对土壤释放N2 O的影响 ;同时考察了土壤NO-3 的形成时间和形成量 .结果表明 ,农田中施加的无机氮肥是大气中N2 O的重要来源 ,而长碳与普碳和尿素相比 ,不但可以明显延后N2 O释放高峰期出现时间 ,而且大多数情况下可以显著减少其释放量 (P <0 .0 1 ) .在 5个月的监测期内 ,与普碳和尿素相比其减少N2 O释放的比例分别为 80 .2 3和 88.41 % ( 1 2 %含水量 ) ,40 .0 0和2 7.59% ( 2 2 %含水量 ) ,无减少作用和 45.88% ( 32 %含水量 ) .本研究结果提示长碳具有作为农田生态系统N2 O减排措施的巨大潜力 ,同时暗示在农业中用长碳代替目前普遍应用的普碳 ,可以减少地下水中NO-3 引起的污染 .

Effect of different nitrogen fertilizers on N_2O emission from soil.

Incubation experiments were made to study the effects of ammonium bicarbonate(AB), urea and modified ammonium bicarbonate(MAB) on N 2O emission from soil and NO - 3 formation in soil (under low(12%), normal(22%) and high (32%) soil moisture conditions). The results showed that the inorganic nitrogen fertilizers applied in fields were the important source of atmospheric N 2O. In most situations, MAB not only greatly delayed the occurrence of N 2O emission peak, but also reduced the amount of N 2O emission significantly (P<0.01), compared with AB and urea. In comparison with AB and urea, the amounts of N 2O emission were reduced by 80.23 and 88.41% (low moisture, 12%),40.00 and 27.59% (normal moisture, 22%) and little reduction and 45.88% (high moisture, 32%), respectively, during a period of 5 month incubation when MAB was applied. It is indicated that MAB was a promising N fertilizer from the aspect of reducing N 2O emission from agroecosystem. The results also implied that applying MAB instead of AB which is used widely in China at present, might reduce the NO - 3 pollution of the underground water.