Determination of Decomposition Rates of Cover Crop Residues and Their Nutrient Release Characteristics

Project Overview

Project Type: Graduate Student
Funds awarded in 2016: $11,906.00
Projected End Date: 12/31/2018
Grant Recipient: University of Minnesota
Region: North Central
State: Minnesota
Graduate Student:
Faculty Advisor:
Dr. Daniel Kaiser
University of Minnesota


  • Agronomic: corn, soybeans


  • Crop Production: cover crops, nutrient cycling, tissue analysis
  • Education and Training: extension
  • Production Systems: general crop production
  • Soil Management: nutrient mineralization

    Proposal abstract:

    Cover crops are increasingly being included in lists of best management practices for water quality, but their adoption among non-organic farmers has been slow. One approach to increasing the use of cover crops is to provide evidence that farmers can use them while either breaking even on costs or even gaining a cost benefit. A potential cost saving from cover crops is from a nitrogen credit—nitrogen from cover crop residues could offset nitrogen needed from fertilizer, lowering this input cost (and gaining environmental benefits at the same time). Measuring nitrogen credits from cover crops requires research on the decomposition of their residues under the following crop. Because organic matter decomposition rates vary widely based on soil type, temperature, moisture, background nutrient levels, and microbial community composition, as well as on the biochemical composition of the plant residue, decomposition must be measured locally in order to make reliable recommendations to local farmers. This study will measure the decomposition rates and nutrient release timing of two common cover crops (cereal rye and medium red clover) under two nitrogen rates (0 lbs/acre and MRNT 150 lbs/acre) in a soybean/corn rotation in Rosemount and Waseca, Minnesota. This data will be used to develop evidence-based Minnesota Agricultural Extension cover crop recommendations (including optimal nitrogen rates and optimal timing of cover crop termination for nutrient release).

    Project objectives from proposal:

    Concrete outcomes from this research include:

    • A Minnesota Agricultural Extension publication regarding the nitrogen credit from select cover crops (in lbs N/acre) in a corn/soybean rotation, including recommendations on date of cover crop termination, and optimal nitrogen rates that will be available to farmers.
    • A journal article in a peer-reviewed journal.
    • A poster or oral presentation at a relevant conference.
    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.