Predictors of short-term nitrogen availability in organic farming systems that utilize warm season cover crops

Project Overview

Project Type: Graduate Student
Funds awarded in 2010: $10,000.00
Projected End Date: 12/31/2013
Grant Recipient: North Carolina State University
Region: Southern
State: North Carolina
Graduate Student:
Major Professor:
Dr. Nancy Creamer
North Carolina State University

Annual Reports


  • Agronomic: buckwheat, millet, peas (field, cowpeas), sorghum sudangrass


  • Crop Production: cover crops, crop rotation, organic fertilizers, tissue analysis
  • Natural Resources/Environment: carbon sequestration
  • Soil Management: green manures, nutrient mineralization, organic matter, soil analysis, soil chemistry, soil quality/health

    Proposal abstract:

    The ability to predict contributions of plant available nitrogen derived from cover crop residue remains a major challenge for growers. Our goal is to identify indicators from soil samples that more accurately predict short-term nitrogen mineralization rates in the weeks-to-months following the incorporation of popular warm season cover crops. We are in the process of investigating changes in light particulate organic matter (L-POM) content as well as a variety of biotic and abiotic soil measurements after the incorporation of five cover crops: buckwheat, cowpea, foxtail millet, sorghum-sudan grass, and a cowpea-millet mix.

    Project objectives from proposal:

    1) Investigate whether cover crop quality is reflected in L-POM measures over the fall season after the incorporation of cover crops.

    2) Identify whether changes in L-POM are correlated with anticipated changes in microbial community characteristics over the fall season after the incorporation of cover crops.

    3) Compare L-POM characteristics with commonly used nitrogen mineralization assays that target the active nitrogen fraction.

    4) Explore the utility of selected soil enzymes as indicators of L-POM quality.

    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.