Rapid abiotic transformation of nitrate in an acid forest soil
Rapid abiotic transformation of nitrate in an acid forest soil
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DOI：
10.1023/a:1010627431722
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发表时间：
2001-01-01
期刊：
影响因子：
4
通讯作者：
Chorover, J
中科院分区：
文献类型：
--
作者：
Dail, DB;Davidson, EA;Chorover, J
硝酸盐固定到有机质中被认为需要土壤微生物的酶的催化。然而，最近的研究表明，添加到土壤中的硝酸盐被迅速固定，这一过程可能包括非生物途径。我们用N-15标记的硝酸盐和亚硝酸盐改良生活和灭菌的土壤，以研究生物和非生物固定。我们报告的快速转化硝酸盐在孵化的O层的森林土壤已被消毒，以防止微生物活性和变性的微生物酶。大约30%，40%和60%的N-15标记的硝酸盐添加到活的，辐照的，或高压灭菌的有机层土壤中消失，从可提取的无机氮池在不到15分钟。在活的和灭菌的土壤中，约5%或更少的硝酸盐以不溶性有机氮的形式回收，其余的被确定为可溶性有机氮。然而，添加N-15-亚硝酸盐，要么失去了气态N或纳入不溶性有机N的形式在活的和无菌的有机土壤。因此，表观非生物硝酸盐固定的命运和途径不同于亚硝酸盐与土壤有机质反应的更知名的机制。硝酸盐和亚硝酸盐添加到活的A-地平线土壤主要是回收的形式添加，这表明硝酸盐的快速转化为可溶性有机氮可能仅限于C-丰富的有机视野。这个温带森林土壤转化的过程中添加的硝酸盐可溶性有机氮不能用既定的机制来解释，但似乎是由于非生物过程中的有机层。
Nitrate immobilization into organic matter is thought to require catalysis by the enzymes of soil microorganisms. However, recent studies suggest that nitrate added to soil is immobilized rapidly and this process may include abiotic pathways. We amended living and sterilized soil with N-15-labeled nitrate and nitrite to investigate biotic and abiotic immobilization. We report rapid transformation of nitrate in incubations of the O layer of forest soils that have been sterilized to prevent microbial activity and to denature microbial enzymes. Approximately 30, 40, and 60% of the N-15-labeled nitrate added to live, irradiated, or autoclaved organic horizon soil disappeared from the extractable inorganic-N pool in less than 15 minutes. About 5% or less of the nitrate was recovered as insoluble organic N in live and sterilized soil, and the remainder was determined to be soluble organic N. Added N-15-nitrite, however, was either lost to gaseous N or incorporated into an insoluble organic N form in both live and sterile organic soils. Hence, the fate and pathway of apparent abiotic nitrate immobilization differs from the better-known mechanisms of nitrite reactions with soil organic matter. Nitrate and nitrite added to live A-horizon soil was largely recovered in the form added, suggesting that rapid conversion of nitrate to soluble organic-N may be limited to C-rich organic horizons. The processes by which this temperate forest soil transforms added nitrate to soluble organic-N cannot be explained by established mechanisms, but appears to be due to abiotic processes in the organic horizon.