Building Organic Soil Health with Green Manure and Cover Crops

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2008: $1,806.60
Projected End Date: 12/31/2008
Region: North Central
State: North Dakota
Project Coordinator:

Annual Reports


  • Agronomic: millet, oats, soybeans, sunflower
  • Vegetables: lentils, peas (culinary), radishes (culinary), turnips


  • Crop Production: cover crops
  • Education and Training: farmer to farmer, on-farm/ranch research
  • Production Systems: organic agriculture
  • Soil Management: green manures, organic matter, soil quality/health

    Proposal summary:

    This project will investigate different termination methods for Sweet Clover green manure followed by a seven-way cover crop mixture to increase soil protection and to increase fertility for the following certified-organic wheat crop. In the Northern Great Plains of the western Dakotas and eastern Montana, Yellow Blossom Sweet Clover is the most popular crop used in organic production systems for soil building as a green manure plow-down. In these systems tillage is used to terminate the crop in late June or early July. Depending on soil types, land topography, precipitation and wind conditions, this tillage can result in erosion problems. With this project, I will be looking at the potential success of two types of management that are new to organic farming here on the Plains. One is terminating the sweet clover with a roller-crimper instead of tillage and the other is seeding a cover crop mixture. I will be evaluating the roller and no-till seeding into the heavy clover residue, and the success of cover crop establishment in different residue levels. By rolling the sweet clover and immediately seeding the cover crop mixture I could also reduce the number of trips across the field, saving fuel and wear and tear on the tractor and implements. I will be working with Pat Carr and Jeff Gunderson at the North Dakota State University Dickinson Research Extension Center on this project. There will be eight test strips, each 20 feet wide and about a quarter-mile long in a certified organic field where I seeded sweet clover in 2008. In one strip I will disk twice and chisel plow once later in the summer. No cover crop will be planted -- this is how I and many other organic producers currently manage our sweet clover green manure during the second year. This will be my control. Another strip will be disked once to terminate the sweet clover, and then 2-3 weeks later my NDSU partners will seed a seven species cover crop mix with their John Deere 750 no-till drill to reduce soil disturbance and maintain the same equipment across the strips. In another strip, they will use their roller/crimper to kill the sweet clover and immediately seed the same seven species cover crop mixture with the same drill in a one-pass operation. In the last strip, sweet clover will be rolled/crimped and then seeded with the same cover crop mixture and no-till drill 2-3 weeks later. This coincides with the cover crop seeding on the tilled sweet clover and may help prevent cover crops going to seed later in the season. Cover crop volunteers could be a problem in the next year. These same strip treatments will be repeated once more but in a different order.

    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.