Colorado farmer Ryan Loflin made history last weekend by harvesting the nation’s first commercial hemp crop in 56 years.

Hemp advocates said Loflin’s harvest is a landmark event that could one day lead to larger-scale domestic farming of hemp for industrial uses such as food additives, cosmetics and building materials.

Hemp is genetically related to marijuana but contains only trace amounts of THC, the psychoactive substance that gets marijuana users high.

Loflin’s 55-acre crop in southeastern Colorado’s Baca County won’t yield large amounts of hemp-seed oil and other by-products but is “quite significant symbolically,” said Tom Murphy, national outreach coordinator for advocacy group Vote Hemp.

The sale of hemp products in the U.S. reached an estimated $500 million last year, according to the Hemp Industries Association. Yet all of the hemp used for the products was imported because federal law prohibits its cultivation in the U.S. under the Controlled Substances Act of 1970. The last known commercial crop was harvested in Wisconsin in 1957.

Colorado’s passage of Amendment 64 paved the way for legal cultivation of hemp, but Loflin chose to plant his crop earlier this year before implementation of the state’s hemp-growing regulations, which are scheduled to take effect next year.

Loflin used social media to line up about 45 volunteers to hand-harvest his crop on Saturday and Sunday. Use of a mechanical combine, he said, would have harmed the plants’ stalks, which can be used in construction materials and for animal bedding.

Loflin said some of his hemp seed will be pressed for oil and subsequently purchased by Dr. Bronner’s Magic Soaps, a major user of hemp oil.

“We’re very excited that Ryan has done this,” said David Bronner, president of the company. “Ryan has kind of busted it open and taken this necessary step to make hemp a viable crop.”

Steve Raabe: 303-954-1948, sraabe@denverpost.com or twitter.com/steveraabedp