Evaluation of soil nitrogen status in japanese agricultural lands with reference to land use and soil types
Evaluation of soil nitrogen status in japanese agricultural lands with reference to land use and soil types
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参考土地利用和土壤类型评估日本农田土壤氮状况
DOI：
10.1080/00380768.2004.10408506
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发表时间：
2004
影响因子：
2
通讯作者：
T. Kosaki
中科院分区：
文献类型：
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作者：
S. Sano;J. Yanai;T. Kosaki
从日本各地收集的农业土壤的氮含量的特点是根据形式和有效性，并参考土地利用和土壤类型。总共收集了147个耕层土壤样品，其中80个来自稻田，67个来自高地，包括各种土壤类型。土壤氮分为无机可提取态氮（Iex-N）、固定态铵态氮（Ifix-N）、有机可矿化态氮（Omin-N）和有机稳定态氮（Osta-N）4个组分。在分析中，通过干燃烧法测定总氮含量。lex-N含量通过用2 mol L-1 KCl溶液提取来测定，lfix-N含量通过在去除有机-N之后用HF-HCl溶液提取来测定。Omin-N含量基于长期培养方法被评估为潜在可矿化N，并且Osta-N含量被计算为总-N含量与上述三个部分的含量之间的差。全氮平均含量为2,593 mg kg-1，其中lex-N、lfix-N、Omin-N和OstaN的含量分别为37、124、159和2,273 mg kg-1。有效态氮（Iex-N和Omin-N）平均占全氮的7.6%，稳定态氮（Ifix-N和Osta-N）平均占全氮的92.4%。假设耕层深度为15 cm，容重为1.0 Mg m-3，则全氮、lex-N、lfix-N、Omin-N和Osta-N的量分别为3，890、56、186、239和3，411 kg ha-1。可利用部分的数量（295 kg ha-1）与年总氮输入量（266 kg ha-1）相当，而稳定部分的数量（3，597 kg ha-1）则大十倍以上。与土地利用方式有关，水稻土的lex-N含量（32 mg kg-1，1.4%）低于高地土壤（43 mg kg-1，1.8%），而Omin-N含量（200 mg kg-1，8.9%）高于高地土壤（108 mg kg-1，4.4%）。由于土地利用没有差异，观察到在稳定的N部分。与此相反，由于土壤类型的差异，这是没有观察到的有效部分，清楚地观察到在稳定的部分（Ifix-N和Osta-N），乐。lfix-N含量在非火山性土壤中（156 mg kg-1，10.0%）高于火山性土壤（54 mg kg-1，1.6%），而Osta-N含量在火山性土壤中（3，639 mg kg-1，93.0%）高于非火山性土壤（1，632 mg kg-1，80.1%）。粘粒和Alo含量解释了土壤固氮含量的42.4%，Alo含量解释了土壤速效氮含量的48.1%。这些结果表明，在日本的农业土壤中，有效氮组分的强烈影响的土地利用，而稳定的N组分主要是由土壤类型，应考虑在农业实践中的土壤N管理和N动态在农业领域。
Abstract The nitrogen content of agricultural soils collected from throughout Japan was characterized according to the form and availability, and with reference to land use and soil types. In total, 147 plow layer soil samples were collected—80 from paddy fields and 67 from upland fields to include various soil types. Soil N was separated into four fractions: inorganic extractable-N (Iex-N), fixed NH4 +-N (Ifix-N), organic mineralizable-N (Omin-N), and organic stable-N (Osta-N). In the analysis, the total-N content was determined by the dry combustion method. The lex-N content was determined by extraction with a 2 mol L-1 KCI solution and the lfix-N content by extraction with a HF-HCI solution after removal of organic-No The Omin-N content was evaluated as the potentially mineralizable N based on a long-term incubation method and the Osta-N content was calculated as the difference between the contents of total-N and the above-mentioned three fractions. The average total-N content was 2,593 mg kg-1, of which the contents of lex-N, lfix-N, Omin-N, and OstaN were 37, 124, 159, and 2,273 mg kg-1, respectively. Thus the available fraction (Iex-N and Omin-N) accounted for 7.6%, and the stable fraction (Ifix-N and Osta-N) for 92.4% of totalN on the average. Assuming that the plow layer depth was 15 cm and the bulk density was 1.0 Mg m-3 , the amounts of total-N, lex-N, lfix-N, Omin-N, and Osta-N were 3,890, 56, 186, 239, and 3,411 kg ha-1 , respectively. The amount of the available fraction (295 kg ha-1) was comparable to the total annual N input (266 kg ha-1), whereas the amount of the stable fraction (3,597 kg ha-1) was more than ten times larger. In relation to land use, the lex-N content was lower (both absolute and relative contents) in paddy soils (32 mg kg-1, 1.4%) than in upland soils (43 mg kg-1, 1.8%), whereas the Omin-N content was higher in paddy soils (200 mg kg-1, 8.9%) than in upland soils (108 mg kg-1, 4.4%). No differences due to land use were observed in the stable N fraction. In contrast, differences due to soil types which were not observed in the available fraction were clearly observed in the stable fraction (Ifix-N and Osta-N), Le. the lfix-N content was higher in non-volcanic soils (156 mg kg-1, 10.0%) than in volcanic soils (54 mg kg-1, 1.6%) whereas the Osta-N content was higher in volcanic soils (3,639 mg kg-I, 93.0%) than in non-volcanic soils (1,632 mg kg-1, 80.1%). Accordingly, the 42.4% of variance of the lfix-N content was explained by the clay and Alo contents and 48.1% of variance of the Osta-N content by the Alo content. These findings showing that, in Japanese agricultural soils, the available N fraction was strongly affected by the land use, whereas the stable N fraction was mainly determined by the soil types, should be taken into account in the management of soil N in agricultural practices and N dynamics in agricultural fields.