氮添加对沙质草地氨挥发及硝态氮淋溶的影响

Effects of nitrogen addition on ammonia volatilization and nitrate leaching of a sandy grassland

采用密闭室法和离子交换树脂袋法,研究了科尔沁沙质草地不同处理(水添加、氮添加、水氮添加)氨挥发的损失量和硝态氮的淋溶量。结果表明:氮添加处理和水氮添加处理显著促进了氨挥发(P<0.05),最大氨挥发速率显著高于对照;氮添加处理和水氮添加处理的氨挥发累积量为111.80和148.64mg·m-2,分别占氮添加量的1.1%和1.5%;水氮同时添加条件下,氨挥发累计量显著高于氮添加处理(P<0.05),水添加处理和对照相比没有显著差异(P>0.05);水氮添加处理显著增加了土壤深度20cm处的硝态氮淋溶量(P<0.05),氮添加处理和水氮添加处理的硝态氮淋溶量分别是对照的1.96和4.22倍,然而在土壤深度40cm处各处理硝态氮淋溶量差异不显著(P>0.05);可见,氮添加和水氮添加均促进了土壤的氨挥发,对硝态氮的淋溶没有显著影响。

With enclosed and static chambers and ion exchange resin bags, this paper studied the effects of water addition （ W）, nitrogen addition （ N）, and water and nitrogen addition （WN） on the ammonia volatilization and nitrate leaching of a sandy grassland in southeastern Keerqin Sandy Land, taking no water and nitrogen addition as the control （CK）. Treatments N and WN promo- ted the ammonia volatilization significantly, and the maximum ammonia volatilization rate was sig- nificantly higher than that of the control （P〈0. 05）. The cumulative amount of ammonia volatili- zation in treatments N and WN was 111.80 mg·m^-2 and 148.64 mg·m^-2, accounting for 1.1% and 1.5 % of the nitrogen added, respectively. The cumulative amount of the ammonia volatilization was significantly higher in treatment WN than in treatment N （ P〈0. 05 ） , but had no significant difference between treatments W and CK. Treatments N and WN increased the leaching amount of nitrate-N at 20 cm soil depth significantly （P〈0.05）, being 1.96 and 4. 22 times of the CK, respectively. No significant difference was observed in the leaching amount of nitrate-N at 40 cm soil depth among the treatments W, N, WN, and CK （P〉0. 05）. The results suggested that both nitrogen addition and water and nitrogen addition promoted the ammonia vol- atilization, but had little effects on the nitrate leaching of the sandy grassland.