Written by Dale R. Mutch - Retired Senior Educator, Michigan State University Extension
Updated by Erin C. Hill - Cover Crop Specialist, Michigan State University
Using cover crops in farming systems is not a new practice. Prior to the development of manufactured fertilizers, cover crops were commonly used to improve soil structure and productivity. Recent economical and environmental concerns have fueled a resurgence in cover crop use. This information sheet is the first in a series designed to provide cover crop information. A team of researchers, MSU Extension agents and Michigan farmers are producing them to address specific cover crop questions. The information comes from research and demonstrations conducted at Michigan State University and on farms throughout Michigan.
Cover crops are planted to improve soil quality - not for harvest and resale. They enhance soils by protecting, improving and providing nutrients and have many purposes, including:
Cover crops can enhance N production and/or reduce leaching. Overseed legume (clovers, medic, etc.) cover into corn, frost-seed into wheat, or late summer-seed to provide nitrogen for future crops. Grass (annual ryegrass, cereal rye, wheat, oilseed radish) can be used to take up excess nitrogen and reduce the potential for groundwater leaching. Erosion control: Cover crops can be used to reduce wind and water erosion. Maintaining ground cover through fall, winter and early spring drastically reduces soil loss. Improving soil quality: Cover crops enhance soil structure while increasing soil biota activity. They reduce soil compaction while increasing water percolation and retention. Cover crops help soils maintain a higher organic matter level than continuous row cropping without cover. They also improve soil aggregation, infiltration and bulk density.
Cover crops can play a role in managing weeds by shading and interfering with weed germination and establishment. Cereal rye produces allelochemicals which suppress weeds. Unfortunately, cover crops can also become weeds. MSU researchers are currently investigating using cover crops for weed control without reducing crop yields.
Cover crops will play an important role in future biological insect control. They have increased Trichograma wasp survival for European corn borer control in seed corn. MSU researchers are investigating using cover crops for biological control programs.
Cover crops can be used as a forage crop and feed source. There are many other uses for cover crops which will be discovered as we increase their use.