Let’s dive right into a topic that has kept PFI cooperators and ISU scientists occupied the last two years – manure, or, more generally, “biosolids.” The Leopold Center for Sustainable Agriculture funded a study of swine hoophouse manure management because there is a potential for nutrient tie-up in the bedding-manure mix that comes from these units. Composting helps improve the fertilizer value of these materials. But composting carries a cost.
First a general cautionary note: the economic numbers appearing with these trials is for illustrative purposes. A component of the project is putting better numbers on the costs of composting and manure handling. You will see some high costs for the treatments involving compost. In those cases the crops have been charged with labor and sometimes equipment for composting. Some people whether cropping operations should be charged with application costs, let alone composting. Those costs are included in this report, but you may want to mentally reallocate them. Ditto for clover or cover crop seed. Any number of items in a farming system don’t pencil out if considered in isolation. As ever, it will be up to you to factor the parts into the whole.