Using multi-species cover crops to improve soil health
This is an excellent presentation by Jay Fuhrer, who works for the Natural Resource Conservation Service in North Dakota, USA. He uses case studies to explain how innovative use of cover crops can boost soil health and productivity, and dramatically reduce the use of artificial fertilizers.
The Burleigh County Soil Conservation District website is a gold mine of inspiration and innovation for farmers of all stripes.
http://bcscd.com/?id=23 downloadable powerpoints about soil health
http://bcscd.com/?id=53 video interviews with farmers