Cover Crops for Climate Change Adaptation and Mitigation

Agriculture and Climate Series

February 25, 2022

The climate crisis and years of unsustainable farming in the United States have resulted in soil erosion, pollinator loss, farmworkers and livestock exposed to extreme heat, and other harmful impacts. In 2019, 10 percent of U.S. greenhouse gas emissions came from agriculture. At the same time, farmers and the land they work are vulnerable to climate impacts such as drought and extreme weather.

Cover crops are one of the many sustainable agricultural practices that can help farmers mitigate and adapt to the climate crisis. This article is the first in EESI’s five-part series on sustainable agricultural practices: cover crops, agroforestry, no-till farming, sustainable livestock grazing, and soil amendments.

What Are Cover Crops?

Cover crops are grown for their environmental benefits and are not harvested as they are not intended for sale or consumption. Instead, they are terminated through a number of different methods before the planting of a cash-crop, which improves soil quality and fertility. These crops are often planted after the harvest of a cash crop, such as corn, and before the planting of the next crop, when fields would otherwise lie fallow. Common cover crops include legumes (e.g., red clover, peas, beans), cereals (e.g., rye, wheat, oats), grasses (e.g., barley ryegrass, millet), and broadleaf species (e.g., buckwheat, mustard). Given the varying characteristics of cover crops, each species provides different advantages, and more than one type of cover crop can be planted to maximize benefits. While cover crop usage has increased over the last decade in the United States, only five percent of cropland in the United States–equal to about 15.4 million acres–used cover crops in 2017.

Fighting Climate Change

Cover crops absorb carbon dioxide through photosynthesis and store the carbon in the soil, helping to mitigate climate change. It is estimated that 20 million acres of cover crops can sequester over 66 million tons of carbon dioxide equivalent per year, equal to the emissions of about 13 million vehicles. However it is uncertain how long sequestered carbon stays in the soil. Nevertheless, coupling cover crops with other sustainable agricultural practices such as no-till or conservation tillage can provide additional and often complementary environmental and climate benefits.

Building Climate Resilience

Cover crops can help farmers be more resilient to climate impacts by increasing the soil’s ability to absorb intense rain and hold onto moisture. This makes crops more resilient to drought, high heat, heavy downpours, and flooding. Cover crops also increase organic matter in the soil, which improves its structure and water-holding capacity, prevents erosion, and reduces the need for fertilizers. Less chemical and soil runoff provides the additional benefit of improving the water quality of surrounding waterways. Cover crops can outcompete weeds, reducing the need for herbicides, and can even disrupt pest cycles, leading to fewer infestations.

Increasing Crop Yields

By preventing erosion, returning organic matter to the soil, and retaining nutrients (or adding them, in the case of legumes), cover crops improve soil fertility, which can increase crop yields. Cover crops also provide habitat for beneficial organisms like pollinators, which are essential for healthy agricultural environments. A 2019 study found that farms that use cover crops have an increase in yield per acre of five percent for soybeans, two percent for corn, and about two and a half percent for wheat.

Cover Crops in Action: Ifft Yorkshires Farm, Illinois

At Ifft Yorkshires Farm in Illinois, farmers began planting cereal rye, a cover crop, after harvesting their corn and before planting their soybeans. This led to an increased soybean yield of five bushels an acre and increased net income by about $36,000. Cover crops were so successful at Ifft Yorkshires Farm that farmers noticed soil quality improvements and were able to reduce herbicide and fertilizer usage. The farm has also started providing cover crop seeds to surrounding farms. Other case studies on the benefits of cover crops can be found across the country from California to New York and Ohio.

Federal Programs That Support Cover Crops

Financial incentives have helped drive cover crop adoption; in 2018, one-third of cover crop acreage planted in the United States received financial assistance from either federal, state, or private organizations. Two major programs administered by the Natural Resources Conservation Service (NRCS) of the U.S. Department of Agriculture (USDA) provide assistance for cover crops:

The Conservation Stewardship Program (CSP) helps farmers and agricultural producers maintain, improve, or adopt new conservation practices such as cover crops. For example, the program can help farmers adopt multi-species cover crops or figure out the appropriate time to plant them. Two million acres of cover crops were enrolled in CSP in 2015, a significant increase from the 350,000 acres enrolled in 2011.
The Environmental Quality Incentives Program (EQIP) provides financial and technical assistance for projects like cover crops that address natural resource concerns and provide environmental benefits. In 2018, EQIP provided $155 million to plant cover crops on 2.4 million acres, and participation in EQIP has significantly increased over the last decade.

State programs, such as the Agricultural Water Quality Cost-Share Program in Maryland and the Cover Crop Insurance Discount Program in Iowa, have also been important for cover crop adoption.

Additionally, during the COVID-19 pandemic, USDA’s Risk Management Agency began offering the Pandemic Cover Crop Program. The program recently provided $59.5 million in premium support for farmers to plant cover crops on 12.2 million acres during the COVID-19 pandemic.

To read all the articles in this series, visit our Sustainable Agriculture series webpage. For more on cover crops, watch or read highlights from EESI’s briefing, Natural Climate Solutions: A Win-Win Solution for Our Environment and Our Economy.

Authors: Savannah Bertrand, Anna Sophia Roberts, and Emma Walker