CCZO -- Soil Geochemistry -- 70-m deep borehole -- Calhoun Long-Term Soil Experiment -- (2010-2010)

Samples were collected from Steve Stone’s property which is adjacent to the Calhoun Long-term forest plots (see map below - click on 'Overview Maps' tab). Three continuous mineral soil cores were collected from 0-14 m with a Geoprobe in Steve Stone’s hardwood forest (“Core Locations” in map). These surficial samples were collected from this location because contemporary vegetation, aerial photography dating back to 1938, and soil profile morphology indicated that European agriculture had minimally affected soils in this hardwood forest. Samples deeper than 14 m were collected from Steve Stone’s pasture, approximately 30 m away from the “core locations”, during the installation of a groundwater well by a private contractor (Gill Drilling Services inc.). Samples from 14-18 m were collected with a three-wing bit auger while samples from 18-67 m were collected with a roller-cone bit. After collection all samples were air-dried, and samples from 0-18 m were sieved to 2 mm.

Texture was measured by the pipette method on 20 g of sample. Soil pH was measured with a continuous flow electrode in deionized water and in 0.01 M CaCl2 with a soil:solution ratio of 0.5 and a 15 minute extraction time. Exchangeable acidity was extracted with 1M KCl (soil:solution=0.002, 30 minute extraction) and titrated to 8.2 with 0.02 M NaOH. Exchangeable calcium, magnesium, potassium, and sodium were extracted with 1 M NH4OAc (soil:solution=0.05, 30 minute extraction) and measured by Atomic Absorption Spectrophotometry. Total aluminum, beryllium, calcium, manganese, silicon, titanium, and zirconium were measured by Inductively coupled plasma atomic emission spectroscopy while total iron, magnesium, phosphorus, potassium, and sodium were measured by Atomic Absorption Spectrophotometry following LiBO2 fusion of pulverized and oxidized (30 minutes at 800 C) subsamples (0.1 g sample, 0.4 g LiBO2, 13 minutes at 1000 C). “Free”-iron and “free”-beryllium (Mehra & Jackson, 1958, DOI: 10.1346/CCMN.1958.0070122) were measured by Atomic Absorption Spectrophotometry after extraction with 1 M NH2OH·HCl in 1 M HCl (soil:solution=0.05, 4 hours at 90 C). Meteoric Beryllium-10 was extracted by KHF and NaSO4 fusion and 10Be/9Be isotopic ratios were measured by accelerator mass spectrometry. Total carbon and nitrogen were measured by combustion on a CE Elantech Flash EA 1112 Elemental Analyzer.

样本采集自史蒂夫·斯托恩的地产，该地产毗邻卡霍恩长期森林样地（详见下述地图 - 点击“概览地图”标签）。在史蒂夫·斯托恩的硬木森林中，使用Geoprobe采集了三个连续的矿物土壤柱样，深度从0至14米（地图上的“柱样位置”）。由于当代植被、追溯至1938年的航空摄影以及土壤剖面形态表明，欧洲农业对这片硬木森林的土壤影响微乎其微，因此从该地点采集了表层样本。深度超过14米的样本是在私人承包商（吉尔钻井服务公司）安装地下水井期间，从史蒂夫·斯托恩的牧场上约30米处的“柱样位置”采集的。14至18米的样本使用三翼钻头采集，而18至67米的样本则使用滚锥钻头采集。所有样本均进行风干处理，0至18米的样本经过2毫米筛孔筛选。采用滴定管法对20克样本进行质地测量。土壤pH值使用连续流动电极在去离子水和0.01 M CaCl2中测量，土壤与溶液的比例为0.5，提取时间为15分钟。可交换酸性物质使用1M KCl提取（土壤与溶液比例为0.002，提取时间为30分钟），并以0.02 M NaOH滴定至8.2。可交换的钙、镁、钾和钠使用1 M NH4OAc提取（土壤与溶液比例为0.05，提取时间为30分钟），并通过原子吸收分光光度法进行测量。总铝、铍、钙、锰、硅、钛和锆通过电感耦合等离子体原子发射光谱法测量，而总铁、镁、磷、钾和钠则在粉碎和氧化（800°C下30分钟）的子样经过LiBO2熔融后，通过原子吸收分光光度法测量。所谓的“游离”铁和“游离”铍（Mehra & Jackson, 1958, DOI: 10.1346/CCMN.1958.0070122）通过1 M NH2OH·HCl在1 M HCl中的提取后，使用原子吸收分光光度法进行测量（土壤与溶液比例为0.05，90°C下4小时）。通过KHF和NaSO4熔融提取大气降水铍-10，并使用加速器质量光谱法测量10Be/9Be同位素比。总碳和氮通过CE Elantech Flash EA 1112元素分析仪的燃烧法进行测量。