A Volumetric Inorganic Carbon Analysis System

Abstract

Measurement of soil organic carbon (OC) is slow and expensive when inorganic carbon (IC) is present. Our objective was to develop an automated volumetric IC analysis system, thus allowing OC to be determined by difference. The system was developed by combining a pressure transducer with a personal computer (PC), data acquisition board, and appropriately developed software. The volumetric system was compared with combustion, neutralization, and sum of Ca + Mg techniques for samples containing up to 60 g kg−1 IC. Correlations between methods showed linear agreement (r2 ≥ 0.994). The volumetric system was more precise for relatively low IC amounts (2.0 g kg−1) and could process 20 samples h−1.

Soil quality response to long-term tillage and crop rotation practices

“…Based on soil pH, neither depth increment appeared to have sufficient inorganic carbon (IC) to warrant volumetric measurement (Wagner et al, 1998), so TC and total organic carbon (TOC) were assumed to be the same.…”

Crop and Soil Responses to Using Corn Stover as a Bioenergy Feedstock: Observations from the Northern US Corn Belt

“…Soil texture was determined using the hydrometer method [30,31]. Soil pH (1:1 CaCl 2 ) [32], total C and N (LECO TRU-SPEC CN analyzer; LECO Corporation, St. Joseph, MI), inorganic C [33], Olsen P and extractable K [34] were determined. Organic C was calculated as the difference between total combustible C and inorganic C as these are calcareous soils.…”

A five-year assessment of corn stover harvest in central Iowa, USA

“…A fourth sub-sample was pulverized before analyzing for total carbon (TC) and total nitrogen (TN) using dry combustion. For samples with pH values greater than 7.3, inorganic C (IC) was also determined (Wagner et al, 1998). The total organic carbon (TOC) values were then calculated as the difference between TC and IC with the latter being zero for samples with pH < 7.3.…”