Rapid screening of soil properties using thermogravimetry

Organic C, N, clay, and carbonate content are basic soil properties, which are commonly assessed by different analytical methods. This study aimed at utilizing temperature-induced dynamics of weight losses to determine these parameters simultaneously without losing precision and accuracy. For this purpose, thermogravimetric profiles of 52 soil samples were recorded and compared with C, N, and textural data obtained from conventional analyses using dry combustion and pipette methods. The samples originated from different climatic regions, land-use systems and parent materials. The results showed that thermal weight losses correlated closely (P < 0.001) with the content of organic C (R-2 = 0.98), total N (R-2 = 0.94), clay (R-2 = 0.87) and CO3-C (R-2 = 0.99) for mineral soil samples, while no such relationships were found in organic soil horizons. For mineral soils, each soil property correlated with a specific interval of temperature-induced weight losses. Application of thermogravimetry to independent additional sets of 250 samples confirmed a reliable estimation of organic C, total N, clay and CO3-C of mineral soils. It is concluded that thermogravimetry allows a simultaneous, rapid and reliable screening of these four properties in mineral soils.