Washington State University

Organic Farming Systems and Nutrient Management

Using Local Sources of Organic Nutrients   CSREES logo

Photo manure spreading

Nutrient imbalances present problems in urban fringe watersheds, with an oversupply of nutrients in some areas of the watersheds. Use of organic materials from livestock farms and recycled urban waste streams can help improve soil productivity and reduce nutrient imbalances, and can contribute to the sustainability of local agriculture. A number of barriers exist to more widespread and efficient use of local organic materials in agriculture. These include concerns about availability of supplies relative to application timing, consistency of materials, compatibility with equipment and farming practices, economic questions, and potential side effects such as weeds, pathogens, and odors. A key issue is the need for better information on nutrient availability. In 2004 we completed a 3-year field and laboratory research project studying nitrogen availability from a range of composted and uncomposted local organic amendments. Research was done at OSU and WSU. 

Organic fertilizer calculator worksheet: A downloadable worksheet for calculating organic fertilizer rates, developed at Oregon State University using the results of this research and subsequent laboratory research by Dan Sullivan at OSU.