Biotic and Abiotic Nitrogen Retention in a Variety of Forest Soils
Biotic and Abiotic Nitrogen Retention in a Variety of Forest Soils
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DOI：
10.2136/sssaj2000.6441503x
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发表时间：
2000-07
影响因子：
2.9
通讯作者：
Dale W. Johnson;W. Cheng;I. Burke
中科院分区：
文献类型：
--
作者：
Dale W. Johnson;W. Cheng;I. Burke
研究了灭菌（非生物）和非灭菌（生物）O 和 A 层中的氮 (N) 固定，以确定生物和非生物过程在森林生态系统氮保留中的相对重要性。我们从华盛顿、内华达、加利福尼亚、田纳西和北卡罗来纳州的多个森林地点收集了样本，这些地点具有不同的土壤类型、植被、氮状况和土壤酸度。这些地点包括固定N 2 和非N 2 固定物种的相邻林分以及由于给定位置的斜坡位置而具有不同N状态的地点。我们用(15 NH 4 ) 2 SO 4 处理了每个地点的O 和A 层样品：通过添加HgCl 2 实现灭菌，事实证明这非常有效。我们发现所有土壤中非生物和生物氮固定水平都很高。加利福尼亚州和内华达州贫氮地区的生物氮固定量比其他地区要高得多，并且与总体氮浓度成反比。生物固定化与所有位点的 pH 值和碱饱和度直接相关，但我们假设这些相关性是由这些参数与氮浓度之间的相关性引起的。非生物氮固定在不同位点上的变化小于生物氮固定，并且与氮浓度或 pH 无关。非生物氮固定的总氮固定百分比变化很大（6-90%），并且与氮浓度正相关。这些结果表明，非生物氮固定在各种土壤类型中都是一个重要的过程。在氮饱和度增加的土壤类型中，生物氮固定量减少，非生物氮固定量占总氮固定量的比例更大。
Nitrogen (N) immobilization in sterilized (abiotic) and non-sterilized (biotic) O and A horizons was studied to determine the relative importance of biotic and abiotic processes in N retention in forest ecosystems. We collected samples from a variety of forest locations in Washington, Nevada, California, Tennessee, and North Carolina with differing soil types, vegetation, N status, and soil acidity. Included among these sites were adjacent stands of N 2 -fixing and non-N 2 -fixing species and sites of differing N status due to slope position at a given location. We treated O and A horizon samples from each site with ( 15 NH 4 ) 2 SO 4 : sterilization was achieved by adding HgCl 2 , which proved to he highly effective. We found significant levels of both abiotic and biotic N immobilization in all soils. Biotic N immobilization was much greater in the N-poor sites in California and Nevada than in the other sites and was inversely related to N concentration overall. Biotic immobilization was directly related to pH and base saturation among all sites, but we hypothesize that these correlations resulted from a correlation between those parameters and N concentration. Abiotic N immobilization varied less than biotic N immobilization across sites and was unrelated to N concentration or pH. The percentage of total N immobilization as abiotic N immobilization varied considerably (from 6-90%), and was positively correlated with N concentration. These results suggest that abiotic N immobilization can be a significant process in a variety of soil types. Across soil types with increasing N saturation, biotic N immobilization decreases and abiotic N immobilization accounts for a greater proportion of total N immobilization.