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.