Dried granulated biosolids offer many potential advantages over dewatered biosolids as an organic fertiliser in terms of application, storage and transport. It is believed that this product may even have potential as a surface applied organic fertiliser for the turf industry in the Sydney Basin. This study which commenced in early 2004, is evaluating the potential impacts and benefits of surface applying granulated biosolids as a fertiliser in recreational landscaping (parks, golf courses etc) and turf industries. This 2 year study is focusing on runoff impacts (especially nutrients) which are to be assessed via simulated rainfall events. Nutrient and heavy metals levels in the soil are to be monitored from plot soil sampling prior to the start of the experiment, at 12 months, and then at the end of the experiment. Pasture response is being assessed by the amount of biomass production on the different treatment plots over time. An evaluation of the decomposition and mineralisation characteristics of the granulated and dewatered biosolid products used in this field trial has been done in the laboratory (field capacity, 25ºC) while attempts to measure the rate of nitrogen mineralisation under field conditions at the site are in progress. Plant uptake of nutrients (NPK) and heavy metals are also be monitored over time. At selected times throughout this experiment the soil is to be assessed for evidence of significant responses from the soil biology to the biosolid applications.

The latest results of decomposition and mineralisation studies, and some of the early runoff water sample results from the first rainfall simulation runs will be presented and discussed on Conference field trip C – “Camden District: Irrigated Soils and Recycled Organic Matter”.