Does Manure Treatment Affect Soil Nitrogen Availability?

Project Overview

Project Type: Research and Education
Funds awarded in 2007: $76,034.00
Projected End Date: 12/31/2009
Region: North Central
State: Wisconsin
Project Coordinator:
Christopher Baxter
University of Wisconsin - Platteville

Annual Reports


  • Animal Products: dairy


  • Soil Management: general soil management

    Proposal abstract:

    An incubation study will be conducted using five soils representative of Wisconsin soil groups and 22 manure samples that represent untreated and treated (anaerobically digested, solid-liquid separated, or composted) manures. Rates of inorganic N release from the various manures will be evaluated and cumulative N released will be correlated to various compositional factors. Outputs will include fact sheets, scientific publications, and presentations aimed at producers, agronomists, and the scientific community. Outcomes will be evaluated through audience questionnaires and by quantifying the increased use of manure treatment and manure analysis for predicting available N.

    Project objectives from proposal:

    The primary outcomes of this project are:
    1) increasing awareness of farmers and agronomists on the effects that manure treatment can potentially have on nitrogen (N) availability,
    2) improving the precision of N-based manure recommendations based on laboratory analysis.

    Increased use of manure treatment such as anaerobic digestion, solid separation, and composting has added variation to this already highly variable material. Current University of Wisconsin recommendations for N availability of manure are based on total N analysis only, use the same availability factors for all dairy manures, and do not account for compositional changes in manure that occur during treatment processes. Farmers using manure treatment and operating under N-based nutrient management guidelines need better estimates of potential N availability from these materials to better manage for economic and environmental sustainability.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.