Cover Crops

The educational materials listed on this page are about Cover Crops.

What is a cover crop? A common definition of a cover crop is a plant that is used as part of a crop rotation to improve the soil, scavenge or add nutrients, smother weeds and as a tool for erosion control. Cover crops are not harvested, but are left in place in no-till farming or turned under, especially in organic farming. Another term for cover crops is green manures, especially when the crop residue is incorporated into the soil.

Cover crops can improve soil fertility by adding organic matter, and they help in nutrient management planning by adding nitrogen to soil or by taking up nutrients in soil after cash crop harvest. Winter cover crops are most common in corn and soybean grain production systems, while spring cover crops or summer cover crops can fit many vegetable production systems. Cover crops improve soil moisture, especially over time as soil organic matter and soil tilth are improved.

Cover crop cocktails are used by many farmers as a way to improve soil health. Cocktails or cover crop mixes usually include a grass cover crop such as cereal rye or annual ryegrass, a legume cover crop like crimson clover or hairy vetch, and sometimes a brassica cover crop like forage radish, sometimes called “tillage radish.” Cover crop benefits from cocktails are often greater than seeding a single cover crop species. Cover crop mixes contribute to pest control by attracting beneficial insects and they may increase weed control by providing more ground cover and leaving more crop residue on the soil surface. Some cover crops can mitigate plant disease by suppression soil pathogens. Cover crop cocktails also attract pollinators, including native pollinators.

Cover crop seed is increasingly available from seed companies. They may also be able to help you with information about cover crop selection as well as best timing and methods of planting cover crops.

Some SARE books will help you decide how and when to grow cover crops. Managing Cover Crops ProfitablyCrop Rotation on Organic Farms, and Building Soils for Better Crops are comprehensive guides or manuals. Another useful resource is the SARE topic brief Cover Crops for Sustainable Crop Rotations, which summarizes the usefulness of rotating cover crops in any cropping system. For organic farming, see the Organic Transitions business planning guide.

Showing 1-18 of 18 results

Estimating Plant-Available Nitrogen Release from Cover Crops

This Oregon State University fact sheet explains the basics of plant-available nitrogen (PAN); when to kill cover crops for the maximum PAN benefit; step-by-step instructions on how to perform site-specific measurements to predict PAN from your cover crop; and case studies from the Willamette Valley.

Highlighting Innovations in Soil Health

On March 8-9, 2021, the National Center for Appropriate Technology (NCAT) held the first Soil Health Innovations conference. Originally scheduled last year as an in-person conference in Montana, the conference was postponed due to COVID and expanded as a nationwide virtual conference with 675 participants. The live stream event included speakers and panels, as well […]

Can Cover-cropping and Grazing Work with Dryland Grain Farming?

Farmers know that planting one crop year after year is asking for trouble. It depletes the soil and leads to increased insect, weed and disease pressures. But in certain places, it’s also been the major agricultural system for decades. In north-central Washington, along the Canadian border, dryland wheat production has been the dominate production system […]

A Sunn Hemp Cover Crop for Soil Health and Nematode Management

These University of Hawaii fact sheets and virtual field day explain how to use sunn hemp as a cover crop to control weeds, nematodes and other pests, add soil nutrients, prevent erosion, and contribute to a more robust and complex community of beneficial nematodes. Available fact sheets include: Using Sunn Hemp as a Cover Crop […]

Sustainable Agriculture Farming Systems Project

Public concerns regarding pesticide misuse, food safety, water use and contamination, and depletion of non-renewable resources have motivated the reevaluation of some of the practices of conventional agriculture and the exploration of alternative, more sustainable approaches to growing food. In 1988, the Sustainable Agriculture Farming Systems (SAFS) project was established at the University of California’s […]

Mixed Cover Crops

An informational video on the pros and cons of planting mixed cover crops which are often used to replace fallow. Focus is on effects of cover crops on soil quality in semi-arid regions.

Cover Crops in Organic Systems: California

This is a collaborative project to build the capacity of conservation professionals to assist organic and transitional farmers in planning and implementing conservation practices through the Environmental Quality Incentives Program Organic Initiative. This guide is part of a series of guides created by Oregon Tilth for use by NRCS staff in the Western Region. This document provide an overview […]

On-Farm Internship Training Binder

The Placer Ag Futures Project was conceived as a response to critical issues affecting local agricultural sustainability. This project was intended to help grow a new crop of agricultural professionals that are trained in sustainable agricultural practices. One part of the Ag Futures Project was the on-farm internship training. The summer internship program consisted of […]

Nutrient Management Plans: Idaho

This is a collaborative project to build the capacity of conservation professionals to assist organic and transitional farmers in planning and implementing conservation practices through the Environmental Quality Incentives Program Organic Initiative. This guide is part of a series of guides created by Oregon Tilth for use by NRCS staff in the Western Region. This document is […]

Nutrient Management Plans: California

This is a collaborative project to build the capacity of conservation professionals to assist organic and transitional farmers in planning and implementing conservation practices through the Environmental Quality Incentives Program Organic Initiative. This guide is part of a series of guides created by Oregon Tilth for use by NRCS staff in the Western Region. This document is an instruction […]

Cover Crops in Organic Systems: Oregon

This document provides an overview of how the USDA Natural Resources Conservation Service NRCS Cover Crop 340 conservation practice can be implemented on organic operations in Oregon.

Cover Crops in Organic Systems: Idaho

This document provides an overview of how the USDA Natural Resources Conservation Service NRCS Cover Crop 340 conservation practice can be implemented on organic operations in Idaho.

Cover Crops in Organic Systems

This document provide an overview of how the USDA Natural Resources Conservation Service NRCS Cover Crop 340 conservation practice can be implemented on organic operations in the Western Region.

Funded Grants on Diverse Ag Topics

Western SARE funding is important for many reasons. It helps researchers develop and test new sustainable farming and ranching techniques. It helps university extension agents and other agricultural professionals get that new knowledge into the hands of producers. And it helps farmers and ranchers conduct their own research on their own land, testing out new […]

Fresh Growth Podcast

Fresh Growth: Approaches to a More Sustainable Future from Western Ag Practitioners introduces you to farmers and ranchers from around the western United States who are finding innovative sustainable practices that enrich the natural resources we all care about. These successful multi-generational operations experiment with new ideas and are making it pay. Listen in as […]

Organic Fertilizer and Cover Crop Calculator

This free online tool compares the nutrient value and cost of cover crops, organic and synthetic fertilizers and compost. Use this Excel Calculator to develop well balanced and cost effective nutrient management programs for your farm.