After their commercial introduction in 1996, genetically engineered (GE), herbicide-tolerant (HT) varieties of corn, soybeans and cotton were rapidly adopted by U.S. farmers. The success of these GE crops led to the deregulation that enabled the commercialization of HT canola in 1998 and HT alfalfa and sugar beets in 2005.

Although legal and regulatory issues limited the spread of GE sugar beets and GE alfalfa during the first decade of the 21st century, adoption rates for these crops have increased rapidly in recent years, according to a new report from the U.S. Department of Agriculture’s Economic Research Service (ERS).

Since 2000, USDA has included survey estimates of the shares of acreage planted using GE corn, cotton and soybeans with insect-resistant and HT traits. ERS researchers added questions to USDA’s 2013 "Agricultural Resource Management Survey" (ARMS) to support similar estimates for alfalfa, canola and sugar beets.

The report notes that some 95% of U.S. canola acres and more than 99% of sugar beet acres harvested in 2013 were planted with GE seeds containing HT traits. Only 13% of U.S. alfalfa acres were planted using GE seeds in 2013, but this slower adoption rate is expected because alfalfa is a perennial crop, and only about one-seventh of the alfalfa acreage is newly seeded each year.

In 2013, approximately 18 million acres of alfalfa, with a production value of $10.7 billion, were harvested in the U.S. Only three crops -- corn, soybeans and wheat -- are grown on more acreage or have more aggregate production value than alfalfa.

In 2006, the Center for Food Safety and other organizations sued USDA's Animal & Plant Health Inspection Service (APHIS), arguing that APHIS’s environmental assessment of GE HT alfalfa was not sufficiently comprehensive and that an in-depth environmental impact statement (EIS) should be conducted. On Feb. 13, 2007, the U.S. District Court for the Northern District of California ruled that APHIS had not adequately assessed the environmental and economic impacts of GE HT alfalfa, as required by the National Environmental Policy Act (NEPA). Consequently, the court vacated APHIS’s deregulation decision and ordered that a NEPA-compliant EIS be prepared (USDA/APHIS, 2010a). The court determined that growers who had already planted GE HT alfalfa would be permitted to harvest, use and sell it. However, new seed sales and new planting were no longer permitted under the court injunction.

APHIS released the EIS for glyphosate-tolerant alfalfa in December 2010. On Jan. 27, 2011, under the authority of the Plant Protection Act of 2000, glyphosate-tolerant alfalfa was fully deregulated. Planting resumed in February 2011.

Although the legal actions did not prevent the deregulation of GE HT alfalfa, “they did slow its adoption,” the report stated. Plantings of GE HT alfalfa were suspended from 2007 to 2010.

Approximately 3.5 million acres of alfalfa were newly seeded in 2013 (14% of the acres that were harvested that year). Nearly one-third of this newly seeded alfalfa acreage was a GE HT variety. Data from ARMS indicate that GE HT alfalfa constituted 13% of the alfalfa acres harvested in 2013.

GE HT alfalfa adoption rates were highest in New York, where approximately 37% of the acres harvested in 2013 were GE HT varieties. Adoption rates were also relatively high in Washington and Colorado.

ARMS data from 2013 suggest that farmers who planted GE HT alfalfa had higher yields than farmers who planted conventional seeds; their yields were 0.53 ton per acre, or approximately 17% higher, on average.

Alfalfa that is genetically engineered to have low lignin content was deregulated in November 2014 after a petition from Monsanto Co. and Forage Genetics International.This trait increases the digestibility of the alfalfa, thereby enhancing the nutritional quality of the derived feed and directly benefiting the consumer (as opposed to HT traits that benefit the producer). ERS noted that this alfalfa varietal has been reported to increase yields by 10-20%, “which may lead to further adoption of GE alfalfa in the near future.”

Read the full report.