Data Set Citation:
When using this data, please cite the data package:
Shibata H and Kurokawa H.
Soil nitrogen mineralization and nitrification rates at elevation gradients
JaLTER-Hakkoda.2.1 (https://db.cger.nies.go.jp/JaLTER/metacat/metacat/JaLTER-Hakkoda.2.1/jalter-en)
General Information:
Title:Soil nitrogen mineralization and nitrification rates at elevation gradients
(ja) 標高傾度での土壌窒素無機化・硝化速度
Identifier:JaLTER-Hakkoda.2.1
Abstract:
Characteristics of soil nitrogen mineralization and nitrification rates by elevation and rate variation with soil temperature along elevation were investigated in Hakkoda Mountain. A total of six study sites were established at 200 m elevation intervals in the elevation range of 400 to 1,400 m above sea level. Net nitrogen mineralization and nitrification rates were determined at each study site by elevation using the burried-bag and resin-core methods. In addition, soil nitrogen mineralization and nitrification rates were determined in situ transplant incubation experiments at each elevation using soil samples collected at 600 m and 1,000 m elevation. (ja) 八甲田山において、標高別の土壌窒素無機化・硝化速度の特性、標高に沿った地温の違いによる速度変化を調べた。標高400〜1,400mの範囲で、標高200mおきに計6地点を調査地に設定した。各調査地においてバリード・バッグ法とレジンコア法を用いて標高別の正味窒素無機化・硝化速度を求めた。また、標高600 mおよび1,000 mで採取した土壌を用いて、各標高における現地移動培養実験を行い、土壌窒素無機化・硝化速度を測定した。
Keywords:
  • nitrogen cycle
    (ja) 窒素循環
  • soil microorganisms
    (ja) 土壌微生物
  • global warming
    (ja) 地球温暖化
  • in situ incubation
    (ja) 現地培養実験
  • elevation gradient
    (ja) 標高傾度
Data Table, Image, and Other Data Details:
Metadata download: Ecological Metadata Language (EML) File
Data Table:Soil nitrogen mineralization and nitrification rates incubated in the field at different elevation / 標高別に現地で培養した土壌窒素無機化・硝化速度 ( View Metadata | Download File download)
Data Table:Net NH4 and NO3 production rates in transplant incubation experiments / 移動培養実験での正味NH4およびNO3生成速度 ( View Metadata | Download File download)

Involved Parties

Data Set Owners:
Individual: Hideaki Shibata (ja) 柴田英昭
Organization:Hokkaido University
(ja) 北海道大学
Position:Professor
(ja) 教授
Address:
N9 W9, Kita-ku,
Sapporo, Hokkaido 060-0809 Japan
(ja) 日本 060-0809 北海道 札幌市
(ja)北区北9条西9丁目
Individual: Hiroko Kurokawa (ja) 黒川紘子
Organization:Forestry and Forest Products Research Institute
(ja) 森林研究・整備機構 森林総合研究所
Position:Chief Researcher
(ja) 主任研究員
Email Address:
hirokokurokawa@gmail.com
Data Set Contacts:
Individual: Hideaki Shibata (ja) 柴田英昭
Organization:Hokkaido University
(ja) 北海道大学
Position:Professor
(ja) 教授
Address:
N9 W9, Kita-ku,
Sapporo, Hokkaido 060-0809 Japan
(ja) 日本 060-0809 北海道 札幌市
(ja)北区北9条西9丁目
Individual: Hiroko Kurokawa (ja) 黒川紘子
Organization:Forestry and Forest Products Research Institute
(ja) 森林研究・整備機構 森林総合研究所
Position:Chief Researcher
(ja) 主任研究員
Email Address:
hirokokurokawa@gmail.com

Data Set Characteristics

Geographic Region:
Geographic Description:The Hakkoda Mountains of Aomori Prefecture, located in the northern part of Honshu Island, Japan / 本州北部に位置する青森県の八甲田山地
Bounding Coordinates:
West:  140.85057  degrees
East:  140.96472  degrees
North:  40.6733  degrees
South:  40.59316  degrees
Mimimum Altitude:1312.0  meter
Maximum Altitude:379.0  meter
Time Period:
Begin:
2010-07-14
End:
2010-10-22

Sampling, Processing and Quality Control Methods

Step by Step Procedures
Step 1:
Description:

Establishment of study sites / 研究地点の設定

The study was conducted in the Hakkoda Mountains of Aomori Prefecture, located in the northern part of Honshu Island, Japan. This mountain range is composed of several peaks over 1,200 m above sea level, the highest of which is Ohdake (40°41ʹN, 140°52ʹE), which rises 1,584 m above sea level. The average annual temperature from 1990 to 2009 at the Sukayu weather station (40°39ʹN, 140°51ʹE, 900 m above sea level) was 4°C to 6°C, annual precipitation was 1,300 to 2,300 mm, and the maximum snowfall was 3 to 5 m. Snow cover disappears in late April at elevations between 400 and 600 m, but remains in June at elevations above 1,200 m. In this mountain range, natural vegetation is relatively well preserved above 300 m elevation. Deciduous broadleaf forests of beech (Fagus crenata Blume) dominate between 400 and 800 m elevation, while subalpine coniferous forests of Abies mariesii Mast are dominant between 1,000 and 1,400 m elevation, with a transition between these two forest types between 800 and 1,000 m elevation. The predominant soil at the study site is immature black-bok soil. Surface soil pH at 0-5 cm depth ranges 3.6-4.2, total carbon content ranges 8-25%, and total nitrogen content ranges 0.3-1.4%. In this area, a total of 14 long-term observation areas for vegetation have been established on the west slope of Akakura-dake (line A) and the east slope of Takata-dake (line B) at intervals of 200 m in elevation from 400 m to 1,400 m in elevation. Taking into account the access to the site and the amount of work, this study has selected 14 sites, of which 379 m (hereinafter referred to as 400 m), 636 m (hereinafter referred to as 600 m), and 776 m (hereinafter referred to as 800 m) on Line B, and 985 m (hereinafter referred to as 1,000 m), 1,200 m, and 1,312 m (hereinafter referred to as 1,312 m) on Line A. 1,400 m in the following), for a total of six sites.
(ja) 研究は本州北部に位置する青森県の八甲田山地で行った。この山脈は海抜1,200m以上のいくつかの峰からなり、最高峰の大岳(北緯40°41ʹ, 東経140°52ʹ)は海抜1,584 mである。酸ヶ湯気象台(北緯40°39ʹ, 東経140°51ʹ、標高900 m)における1990年から2009年の年平均気温は4℃~6℃、年降水量は1300~2300 mm、最大積雪は3~5mであった。標高400〜600 mでは4月下旬に積雪がなくなるが、標高1,200 m以上では6月に積雪が残る。この山脈では、標高300 m以上では自然植生が比較的よく保たれている。標高400〜800mでは、ブナ(Fagus crenata Blume)の落葉広葉樹林が、標高1,000〜1,400mにはオオシラビソ(Abies mariesii Mast)の亜高山針葉樹林が優占し、標高800〜1,000mはそれら2種類の森林が移行している(Hikosaka et al. 2021)。研究地の主要な土壌は未熟黒ボク土である。深さ0〜5cmの表層土壌pHは3.6〜4.2、炭素含有率は8〜25%, 窒素含有率は 0.3〜1.4%の範囲にある。この地域では植生の長期観察区が赤倉岳西斜面(Aライン)と高田大岳東斜面(Bライン)に標高400 mから1,400 mまで標高200mおきに計14ヶ所が設置されている。本研究では現地へのアクセスや作業量を考慮に入れて、そのうちBラインの標高379 m(以下では400 mと表記)、636 m(以下では600 mと表記)、776 m(以下では800 mと表記)、Aラインの985 m(以下では1,000 mと表記)、1,200 m、1,312 m(以下では1,400 mと表記)の計6サイトを用いた。

Step 2:
Description:

In situ soil incubation experiments / 現地土壌培養実験

The burried-bag and resin-core methods were used to determine the rates of nitrogen mineralization and nitrification in soils. Both methods can determine the net nitrogen mineralization and nitrification rate in response to changes in soil temperature during the incubation period under conditions where there is no effect of nitrogen absorption by vegetation in the field. The burried-bag method is a widely used method in which soil is placed in polyethylene bags and backfilled into the soil at the site for incubation. In the resin core method, soil is placed in a polyvinyl chloride cylindrical tube, and an ion exchange resin capable of adsorbing ions is attached to the upper and lower ends of the cylinder for incubation. Therefore, the net nitrogen mineralization and nitrification rate under the influence of rainfall infiltration can be determined. In other words, the net nitrogen production rate during the incubation period can be evaluated by separating the net change of N pool in the soil and the amount of N leaching from the soil to the lower layers (the ion exchange resin column at the upper end allows natural rainfall to infiltrate directly, while preventing ions from entering the soil). Five replicates of mineral soil (consisting primarily of A layer) from 0-10 cm depth were collected within each elevation site in July 2010 and mixed well; a 5 mm mesh sieve was used to remove coarse roots and gravel from the mixed soil samples. Those mixed soil samples collected from each elevation site were used for field soil culture at the same site where the soil samples were collected in the manner described below (called "elevationnal incubation experiment"). Soil samples collected at each elevation site were field cultured using two methods: the burried-bag method and the resin-core method. Approximately 50 g of fresh soil was placed in a polyethylene bag with a zipper and backfilled near the center of the depth at which it was collected (approximately 5 cm deep) (burried bag method). Approximately 100 g of fresh soil was also placed in a vinyl chloride cylindrical container (150 cm3, inner diameter 6.7 cm), and 40 g of ion exchange resin (Amberlite MB-1, Organo Co. Ltd.) was attached to the top and bottom ends of the cylindrical container (approximately 2 cm thick) of the same diameter (resin core method). The resin core container (soil + ion exchange resin) was backfilled in the field so that the ion exchange resin column at the top end was at the same level as the ground surface. To measure soil temperature during the incubation period, soil temperature sensors with data loggers were buried 5 cm deep in the soil at each elevation site, and soil temperature was measured every 10 minutes. Soils at elevations of 600 m (beech zone) and 1,000 m (giant birch zone) were buried and incubated using the burried-bag method described above, with five replications at each elevation site (tramsplant incubation experiment). Both the elevational incubation and transplant incubation experiments were conducted over a period of approximately 90 days from mid-July to mid-October 2010 (each incubation day was accurately recorded and used for data analysis).
(ja) 土壌の窒素無機化・硝化速度を調べるために、バリード・バッグ法とレジンコア法を用いた。どちらも現地において植生による窒素吸収の影響が無い条件下で、培養期間の地温変化に応じた正味の窒素無機化・硝化速度を求めることができる方法である。バリード・バッグ法は土壌をポリエチレン袋に入れて現地の土壌内に埋め戻して培養する方法として広く用いられている。レジンコア法では、塩化ビニル円筒管に土壌を入れ、円筒の上下端にイオンを吸着できるイオン交換樹脂を取り付けて培養を行う。そのため、降雨浸透の影響下における正味の窒素無機化・硝化速度を求めることができる。すなわち、培養期間内の窒素正味生成速度の内訳として、土壌内における正味変化と、土壌から下層への溶脱量に分離して評価することができる(なお、上端のイオン交換樹脂カラムは自然降雨をそのまま浸透させる一方、土壌へのイオン流入を防ぐ機能を有する)。 2010年7月に各標高のサイト内から0〜10 cm深の鉱質土壌(主にA層からなる)を5反復で採取し、よく混合した。5 mmメッシュの篩を用いて、混合土壌試料から粗大根系や石礫を取り除いた。各標高サイトから採取したそれらの混合土壌試料を用いて、以下で述べる方法で土壌試料を採取したサイトと同じサイトで現地土壌培養を行った(標高別培養実験)。 各標高サイトで採取した土壌試料を用いて、バリード・バッグ法、レジンコア法の2種類の方法で現地培養を行った。約50 gの新鮮土壌をチャック付きのポリエチレン袋に入れ、採取した深さの中央付近(深さ約5 cm)に埋め戻した(バリード・バッグ法)。また、約100 gの新鮮土壌を塩化ビニル製円筒容器(150 cm3, 内径6.7 cm)に入れ、円筒容器の上下端には同じ径の塩化ビニル製円筒容器(厚さ約2 cm)に40 gのイオン交換樹脂(アンバーライト MB-1、オルガノ社製)を取り付けた(レジンコア法)。上端のイオン交換樹脂カラムが地表と同じ高さになるようにレジンコア容器(土壌+イオン交換樹脂)を現地に埋め戻した。培養期間中の地温を計測するため、データロガー付き地温センサーを各標高サイトで土壌深5 cmに埋設し、10分ごとの地温を計測した。 また、標高600 m(ブナ帯)、1,000 m(オオシラビソ帯)の土壌を用いて、上で述べたバリードバッグ法により、各標高サイトで5反復となるように、それぞれ埋設・培養した(移動培養実験)。 標高別培養実験、移動培養実験は共に2010年7月中旬〜10月中旬の約90日間で行った(各培養日数は正確に記録し、データ解析に用いた)。

Step 3:
Description:

Chamical analysis / 化学分析

Soil was chemically analyzed for pre- and post-incubation samples using the methods described below. Soil moisture content was determined by drying fresh soil at 110°C for at least 48 hours and weighing before and after. To 10 g of fresh soil, 100 mL of a 1 mol L-1 potassium chloride (KCl) solution was added and shaken for 1 hour. For the ion exchange resin, 4 g of ion exchange resin was extracted with 250 mL of 1 mol L-1 potassium chloride (KCl) solution by shaking. After shaking, the extract was filtered through quantitative filter paper (Advantech, 5B). The extract was stored in a freezer until concentration analysis. The concentrations of ammonium-nitrogen (NH4+) and nitrate-nitrogen (NO3-) in the soil and ion exchange resin extracts were determined by colorimetric determination using a continuous flow analyzer (BL Tech, AACS-4).
(ja) 土壌は培養前と培養後の試料について、以下に述べる方法で化学分析を行った。土壌含水率は新鮮土壌を110℃、48時間以上で乾燥させ、前後で重量を測定して求めた。新鮮土壌10 gに1 mol L-1の塩化カリウム溶液100 mLを加えて1時間振盪した。イオン交換樹脂については4 gのイオン交換樹脂に対して、1 mol L-1の塩化カリウム溶液250 mLで振盪抽出した。振盪後の抽出液を定量濾紙(アドバンテック社製、5B)で濾過し、抽出液を得た。抽出液は濃度分析まで冷凍庫で保管した。土壌及びイオン交換樹脂の抽出液に含まれるアンモニウム態窒素(NH4+)、硝酸態窒素(NO3-)濃度は、連続流れ分析装置(BLテック社製、AACS-4)を用いて比色定量法で求めた。

Instrument(s): Continuous flow analyzer (BL Tech, AACS-4) / 連続流れ分析装置(BLテック社製、AACS-4)
Step 4:
Description:

Data processing / データ処理

The nitrogen content in the soil and ion exchange resin was converted from the concentration in the extract solution to the content per dry weight of soil using the sample weight used for extraction and its water content. The change in nitrogen content per dry soil before and after incubation was divided by the number of incubation days to obtain the net rate of change per day (mg N kg-1 day-1). For resin cores, the net rate of change in the soil for NH4+ and NO3- and the rate of leaching of both ions to the lower layer (the amount of nitrogen ions trapped by the ion exchange resin in the lower end column) were summed as the net production rate.
(ja) 土壌及びイオン交換樹脂に含まれる窒素含有率は、抽出液に含まれる濃度から、抽出に用いた試料重量とその含水率を用いて、土壌乾燥重量当たりの含有率に換算した。培養前後における乾燥土壌あたりの窒素含有率の変化量を培養日数で除して、1日あたりの正味変化速度(mg N kg-1 day-1)を求めた。レジンコアについては、NH4+とNO3-の土壌内での正味変化速度、両イオンの下層への溶脱速度(下端カラムのイオン交換樹脂に捕捉された窒素イオン量)の合計値を正味生成速度とした。

Data Set Usage Rights

Access Control:
Auth System:JaLTER
Order:allowFirst
Allow: [read] public
Additional Metadata
Metadata download: Ecological Metadata Language (EML) File