Nitrogen additions affect litter quality and soil biochemical properties in a peatland of Northeast China
Nitrogen additions affect litter quality and soil biochemical properties in a peatland of Northeast China
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DOI：
10.1016/j.ecoleng.2016.12.025
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发表时间：
2017-03-01
影响因子：
3.8
通讯作者：
Tan, Wenwen
中科院分区：
文献类型：
--
作者：
Song, Yanyu;Song, Changchun;Tan, Wenwen
氮 (N) 是许多泥炭地生态系统中的限制性养分。氮沉降增强是全球气候变化的一个主要组成部分，它影响生态系统碳 (C) 平衡，并通过改变植物和土壤特性来改变土壤碳储存。然而，人们对氮沉降增强对泥炭地生态系统的影响知之甚少。我们在中国东北大兴安岭以Eriophorum vaginatum为主的泥炭地进行了为期两年的氮添加田间试验。采用四个水平的氮处理：（1）CK（不添加氮），（2）N1（6 g N m（-2）yr（-1）），（3）N2（12 g N m（-2）yr（-1））和（4）N3（24 gN m（-2）yr（-1））。植物和土壤材料在第二个生长季节结束时收获。添加氮增加了凋落物氮和磷 (P) 含量，以及 S-葡萄糖苷酶、蔗糖酶和酸性磷酸酶活性，但降低了凋落物 C:N 和 C:P 比率。凋落物碳含量保持不变。添加氮增加了浅层土壤（0-15 厘米深）中有效的 NH4+-N 和 NO3--N 以及总革兰氏阳性 (Gram+)、革兰氏阴性 (Gram-) 和总细菌磷脂脂肪酸 (PLFA)。这些PLFA的增加伴随着土壤不稳定有机碳（微生物量碳和溶解有机碳）的减少，并且似乎加速了分解并降低了土壤碳库的稳定性。添加氮会抑制浅层土壤中的蔗糖酶和脲酶活性以及深层土壤（15-30 厘米深度）中的酸性磷酸酶活性。总之，这些发现表明，泥炭地中氮沉积的增加可能会加速凋落物的分解和不稳定碳的损失，并改变微生物的生物量和功能。 (C) 2016 Elsevier B.V. 保留所有权利。
Nitrogen (N) is a limiting nutrient in many peatland ecosystems. Enhanced N deposition, a major component of global climate change, affects ecosystem carbon (C) balance and alters soil C storage by changing plant and soil properties. However, the effects of enhanced N deposition on peatland ecosystems are poorly understood. We conducted a two-year N additions field experiment in a peatland dominated by Eriophorum vaginatum in the Da Xing'an Mountains, Northeast China. Four levels of N treatments were applied: (1) CK (no N added), (2) N1 (6 g N m(-2) yr(-1)), (3) N2 (12 g N m(-2) yr(-1)), and (4) N3 (24 gN m(-2) yr(-1)). Plant and soil material was harvested at the end of the Second growing season. N additions increased litter N and phosphorus (P) content, as well as S-glucosidase, invertase, and acid-phosphatase activity, but decreased litter C:N and C:P ratios. Litter carbon content remained unchanged. N additions increased available NH4+-N and NO3--N as well as total Gram-positive (Gram+), Gram-negative (Gram-), and total bacterial phospholipid fatty acids (PLFA) in shallow soil (0-15 cm depth). An increase in these PLFAs was accompanied by a decrease in soil labile organic C (microbial biomass carbon and dissolved organic carbon), and appeared to accelerate decomposition and reduce the stability of the soil C pool. Invertase and urease activity in shallow soils and acid-phosphatase activity in deep soils (15-30 cm depth) was inhibited by N additions. Together, these findings suggest that an increase in N deposition in peatlands could accelerate litter decomposition and the loss of labile C, as well as alter microbial biomass and function. (C) 2016 Elsevier B.V. All rights reserved.