They are certified by Oregon Tilth Certified Organic (OTCO), an internationally recognized symbol of organic integrity (this certification exceeds the United States Department of Agriculture USDA organic standards). (catfooddispensersreviews.com)
She was a director of Seattle Tilth from 2009 to 2012. (kyl.com)
For example, land once available for crops is disappearing under tarmac and cement as the world's cities grow, and even with a projected population peak of 9bn, an estimated additional 1.5 million square kilometers of tilth and pasture would be lost to the cities by 2030. (climatenewsnetwork.net)