The Effects of Land-use, Tillage and Earthworms on Biosolid - Soil Interactions

Conservation agricultural practices, including reducing tillage, are becoming more popular across the globe to help combat soil degradation and depletion of organic carbon caused by long term intensive agriculture. At the same time, the reintroduction of organic materials to agricultural land provides an end use for waste products while reportedly having beneficial effects on soil quality. Biosolids are one form of organic material derived from wastewater treatment. Their disposal to land is regulated through assurance schemes and codes of practice that require them to be mechanically incorporated into the soil in most instances, which is incompatible with the increasing use of minimal or no-tillage agriculture. This thesis aims to assess the possibility of enhanced benefits from applying biosolids under reduced tillage, and to evaluate the possibility of updating regulations to allow for the surface application of biosolids.