An essential sustainable farming practice faces one big limitation: Land to produce seeds

June 11, 2020

As farmers across the globe look to grow food more sustainably - with less water, fertilizer, pesticides and other environmental impacts - the use of cover crops is becoming more popular. These crops, which are often grasses or legumes, but also many other types of plants, are generally grown between the harvest and planting season of the land's main cash crop, to reduce erosion, build soil fertility and control weeds, among other benefits. Their use has jumped in recent years. From 2012 to 2017, U.S. cover crops increased to 6.2 million hectares, an increase of 50 percent.

But the growth in cover cropping may soon hit a ceiling: planting millions of acres of cover crops will require huge extensions of land to produce cover crop seed. Between 3 and 6 percent of the 92 million acres of cropping land currently used for corn (maize) in the U.S. may be required to produce cover crop seed for that land area.

Researchers estimated that range based on 18 cover crops currently used on corn farmlands. The study was published June 11 in Communications Biology, a Nature journal, by scientists at the University of Minnesota, University of Southern California, Saint Louis University, University of Hawaii, and the Alliance of Bioversity International and CIAT.

"Cover cropping works," said Colin Khoury, a crop researcher at the Alliance, who co-authored the study. "But it's not yet commonly used even though it's widely praised."

Despite its growing popularity, only 1.7 percent of U.S. cropland currently employs cover crops. Universities, nonprofits and industry are driving growth in cover crop use through research, advocacy and education.

Cover crops make soil healthier - they reduce erosion and help restore nutrients and carbon, and create the conditions where soil can better hold moisture, all of which can help mitigate climate change as well as support farmers' adaptation of their crops to hotter and drier conditions. They help control weeds and pests and can reduce the use of pesticides and chemical fertilizers, which have highly valued downstream benefits.

"Water quality improvements are seen quite rapidly when you use cover crops," said Michael Kantar, a plant breeder at the University of Hawaii.

Without investment in improving cover crops, the land needed to produce enough seed to widely scale up their use would likely cut into land used to produce cash and food crops. This is because cover crops do not generally reach a seed-producing age when planted on land between harvest and planting of food crops.

While 3-6 percent of U.S. corn farmland may not seem like much, it only takes 0.2-0.7 percent of that land to produce corn seed. Some of the cover crops that provide the greatest environmental benefits have the poorest seed production, meaning that as much as 12 percent of the U.S. corn belt would be needed to produce cover crop seed of those crops. This would be equivalent to producing 44 million metric tons less corn on those farmlands.

Invest, and look south

The authors said demand could overcome the land limitation - as long as this demand is channeled into investments in breeding programs to increase cover crop seed yield. Scientists can improve cover crops using conventional breeding techniques or biotechnological innovations, including CRISPR/Cas9 technology - essentially the same methods already used to increase seed yields in food and cash crops.

"It's not a prohibitive investment," said Kantar. "We need more dedicated breeding programs for cover crops."

Alternatively, a cover crop seed industry could expand into other temperate or even tropical growing regions, giving new income opportunities to farmers who could produce seed for an emerging, global market for more sustainable crop production.

"The economic and environmental benefits of expanded cover cropping likely surpass needed investments by a very wide margin," said Bryan Runck, the study's lead author from the University of Minnesota.
-end-
About the Alliance

The Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT) delivers research-based solutions that harness agricultural biodiversity and sustainably transform food systems to improve people's lives. Alliance solutions address the global crises of malnutrition, climate change, biodiversity loss, and environmental degradation. The Alliance is part of CGIAR, a global research partnership for a food-secure future. http://www.bioversityinternational.orghttp://www.ciat.cgiar.orghttp://www.cgiar.org

International Center for Tropical Agriculture (CIAT)

Related Corn Articles from Brightsurf:

Making sense of a universe of corn genetics
A new study details the latest efforts to predict traits in corn based on genomics and data analytics.

Redefining drought in the US corn belt
As the climate trends warmer and drier, global food security increasingly hinges on crops' ability to withstand drought.

Speedy recovery: New corn performs better in cold
Around the world, each person eats an average of 70 pounds of corn each year, with even more grown for animal feed and biofuel.

US corn yields get boost from a global warming 'hole'
The global average temperature has increased 1.4 degrees Fahrenheit over the last 100 years.

Genetic discovery may improve corn quality, yields
Researchers may be able to improve corn yields and nutritional value after discovering genetic regulators that synthesize starch and protein in the widely eaten grain, according to a Rutgers-led study.

Pollen genes mutate naturally in only some strains of corn
Pollen genes mutate naturally in only some strains of corn, according to Rutgers-led research that helps explain the genetic instability in certain strains and may lead to better breeding of corn and other crops.

Fungal mating: Next weapon against corn aflatoxin?
Native fungi combinations show promise against aflatoxin.

Scientists discover new 'architecture' in corn
New research on the US's most economically important agricultural plant -- corn -- has revealed a different internal structure of the plant than previously thought, which can help optimize how corn is converted into ethanol.

Breeding corn for water-use efficiency may have just gotten easier
With approximately 80 percent of our nation's water supply going towards agriculture, it's fair to say it takes a lot of water to grow crops.

Changing temperatures are helping corn production in US -- for now
Increased production of corn in the US has largely been credited to advances in farming technology but new research shows that changing temperatures play a significant role in crop yield.

Read More: Corn News and Corn Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.