Examining black soldier fly (Hermetia illucens) composting for urban ag specialty crop production
Urban farmers face many unique challenges associated with the urban environment in which they produce. One of the most expensive and limited resources is access to healthy soils. There is often low organic matter and industrial contaminants present in urban soils, resulting in the need for remediation, such as capping and importing topsoil and compost. Recently, black soldier fly larvae (Hermetia illucens; BSF) have been recognized as an efficient organism used to break-down organic matter and produce a soil amendment comparable to traditional fertilizers. These fly larvae can feed on a wide range of organic waste (plant material, biosolids, food waste, etc.), can break down contaminants such as pharmaceuticals or pesticides, and impact the bioavailability of heavy metals. The resulting material is a digestate that can be applied as a soil amendment, much like the vermicomposting processes of worms. Fly pupae can be harvested and used as a nutrient dense feedstock for livestock or reared to adults to continue the cycle of composting. Knowledge gaps remain regarding the impact of feedstock on the nutritional quality of the digestate for crop production and the application and implementation of BSF composting on-farm. We found that larval weight is unaffected by diet streams, however, larval length is improved on food waste streams. Additionally, crop growth varies when grown with BSFL digestate.