Biotic and abiotic processes of nitrogen immobilization in the soil-residue interface
Biotic and abiotic processes of nitrogen immobilization in the soil-residue interface
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DOI：
10.1016/j.soilbio.2004.02.024
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发表时间：
2004-07-01
影响因子：
9.7
通讯作者：
Kosaki, T
中科院分区：
文献类型：
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作者：
Moritsuka, N;Yanai, J;Kosaki, T
腐烂的植物残留物和土壤之间的界面是土壤无机氮微生物固定的热点。最近对森林和草原土壤的研究表明，植物残留物的存在也可以诱导无机氮的快速非生物固定。因此，我们研究了（1）氮固定如何随距土壤-残留物界面的距离而变化，以及（2）农业土壤中是否发生非生物固定。使用一个盒子来评估土壤-残渣界面中氮固定的时空变化，该盒子能够从 4 毫米厚的残渣室 (RC) 中以 2 毫米的增量对土壤进行采样。 RC内均匀填入含有磨碎的植物残渣（米糠、稻草或山毛榉叶）的稻土，填充量为50 g干物质kg(-1)。周围隔间的土壤中没有残留物。在25℃有氧培养5、15和30天后，对每个隔室中的土壤进行分析。 5 天后，在所有残留物处理中，从 RC 延伸至少 10 毫米的土壤中，无机氮发生显着消耗，表明无机氮向 RC 广泛扩散。对于米糠、稻草和山毛榉叶处理，RC 10 毫米内的消耗量分别为 5.0、4.3 和 3.4 mg。另一方面，米糠和稻草处理的 RC 中微生物氮显着增加（分别为 11 mg 和 5.5 mg），而山毛榉叶处理的 RC 中微生物氮则不显着（0.06 mg）。每个RC 10 毫米内的无机氮减少量分别增加了221%（米糠）、129%（稻草）和1.7%（山毛榉叶）。此后，氮矿化率超过了固定化率，无机氮水平在15天（米糠）和30天（稻草和山毛榉叶）时几乎恢复到原来的水平。这些结果表明，在米糠和稻草附近的土壤中，生物固定化占主导地位，在山毛榉叶附近的土壤中，生物固定化占主导地位。培养 5 天后，山毛榉叶子附近的微生物和可溶性有机氮没有显着增加，进一步表明非生物过程导致无机氮转化为不溶性有机氮。(C) 2004 Elsevier Ltd. 保留所有权利。
The interface between decaying plant residues and soil is a hotspot for microbial immobilization of soil inorganic N. Recent studies on forest and grassland soils have demonstrated that rapid abiotic immobilization of inorganic N is also induced by the presence of plant residues. We, therefore, examined (1) how N immobilization varies with distance from the soil-residue interface and (2) whether abiotic immobilization occurs in agricultural soils. Spatiotemporal changes of N immobilization in the soil-residue interface were evaluated using a box that enabled soil to be sampled in 2 mm increments from a 4 mm-thick residue compartment (RC). The RC was filled with paddy soil containing ground plant residue (rice bran, rice straw or beech leaves) uniformly at a rate of 50 g dry matter kg(-1). Soil in the surrounding compartments contained no residue. After aerobic incubation for 5, 15 and 30 days at 25 degreesC, soils in each compartment were analyzed. After 5 days, significant depletion of inorganic N occurred throughout a volume of soil extending at least 10 mm from the RC in all residue treatments, suggesting extensive diffusion of inorganic N towards the RC. The depletion within 10 mm of the RC amounted to 5.0, 4.3 and 3.4 mg for rice bran, rice straw and beech leaf treatment, respectively. On the other hand, microbial N had increased significantly in the RC of the rice bran and rice straw treatments (11 mg and 5.5 mg, respectively) and insignificantly in the RC of the beech leaf treatment (0.06 mg). This increase amounted to 221% (rice bran), 129% (rice straw) and 1.7% (beech leaves) of the decrease in inorganic N within 10 mm of each RC. Thereafter the rate of N mineralization exceeded that of immobilization, and inorganic N levels had recovered almost to their original level by 15 days (rice bran) and 30 days (rice straw and beech leaves). These results suggested the predominance of biotic immobilization in soil near rice bran and rice straw and of abiotic immobilization in soil near beech leaves. No significant increase in both microbial and soluble organic N in the vicinity of beech leaves after incubation for 5 days further suggested that the abiotic process was responsible for the transformation of inorganic N into the insoluble organic N. (C) 2004 Elsevier Ltd. All rights reserved.