Molecular weight distribution of soluble organics from laboratory- manipulated surface soils

To examine the effects of disturbances on solubilization of organics, three A horizons and one O horizon were exposed to air drying, waterlogging, addition of urea, addition of ash, and addition of ash in combination wtih heating at 250°C. Urea and heat-plus-ash treatments yielded up to 17 times more soluble organic carbon (SCO) than controls, and other treatments yielded up to three times more than controls. Urea treatment yielded a higher proportion of SOC in the >14 000-dalton class than in the controls, while air drying resulted in a lower proportion. Both the quantity and quality of soluble organics can be influenced by soil disturbances, but the specific response varies with the type of disturbance. -from Authors