As of my last update in early 2023, Bill Crabtree, also known as "No-Till Bill," is an agronomist and an advocate of no-tillage farming practices. He is not widely recognized as a mainstream author but rather is known for his contributions to the agricultural sector, specifically in the field of sustainable farming. Crabtree has worked to educate farmers about the benefits of conservation agriculture, focusing on soil health and the reduction of soil erosion through minimal soil disturbance. He may have authored or contributed to technical papers, guides, or books on the subject of sustainable agriculture, but please note that there might be multiple individuals named Bill Crabtree, and additional context may be necessary to provide a more specific description.