부산대학교 도서관

Growing demands for sustainable land use challenges the management of soil organic matter (SOM). Research on SOM stabilization mechanisms during the last decades opened access to new approaches of SOM assessment. This study tried to empower this trend with a focus on the interrelations between soil components including clay, organic carbon and bound water toward a unifying assessment for practical land use. Soil samples from different regions of the world were collected, air-dried, sieved and equilibrated to 76 % relative humidity prior to analysis. Thermogravimetry was applied to search for a relationship between thermal mass losses corresponding to soil components and mass losses on ignition (MLI) between 110 and 550 °C. The results refer to a predictability of MLI from thermal mass losses in two 10 °C temperature steps (TML), which are both closely correlated with the content of clay and soil organic carbon (SOC), respectively. We found a relationship MLI = 10 × TML130-140 °C + 25 × TML320-330 °C − 2 with R = 0.98, applicable for soils with a wide range of properties. Using previous results, this equation can be rewritten as SOC = 0.48 × MLI-0.12 × clay + 0.2, which is similar to previously published relationship. The application of equation to plots with varying fertilization in long-term field experiments revealed deviations, which could be explained by different amounts of biologically degradable, non-humified, fresh organic residues or similar organic admixtures. This assumption was tested by application to untouched by human activity soils before and after laboratory incubation. The microbiological decay of SOM in incubated samples led to significantly lower differences of calculated and measured MLI, confirming a decrease in the amount of fresh organic matter. We conclude that thermogravimetry is applicable to study interrelations between soil components and to assess soil organic carbon content and quality. [ABSTRACT FROM AUTHOR]