pH-Induced Mobilization of Carbon in Soil Treated with Waste Streams.

Title: pH-induced mobilization of carbon in soil treated with waste streams

Abstract: Large amounts of both solid and liquid waste streams are added to soil as a source of carbon and nutrients. Some of these waste streams include biosolids, manures, and domestic and industrial effluents. These waste streams act both as a source and sink for soil carbon. These waste streams impact soil carbon dynamics by alternating soil properties including pH, ionic strength and cation exchange capacity. pH influences carbon dynamics in soil through its effects on adsorption and solubilisation of carbon. In this study, the effect of two waste streams which varied in their pH and cationic composition (potassium-based winery effluent and sodium-based dairy factory effluent) on the mobilization of carbon in a range of soil samples was examined. The soil samples were treated with these two waste streams and the mobilization of carbon was monitored by measuring dissolved organic carbon using rhizon samplers.  Both waste streams increased soil pH, thereby increasing the mobilization of carbon as measured by dissolved organic carbon. However the rate of mobilization varied between these two waste streams which was attributed to the difference in the cationic composition. The sodium-based dairy factory effluent resulted in a greater mobilization of carbon than the potassium-based winery effluent.