An integrated system of plant and animal production practices having a site specific application that will, over the long-term: satisfy human food and fiber needs; enhance environmental quality and the natural resource base upon which the agriculture economy depends; make the most efficient use of nonrenewable resources and integrate, where appropriate, natural biological cycles and controls; sustain the economic viability of farm/ranch operations; and enhance the quality of life for farmers/ ranchers and society as a whole.

For more information - here are some web sites and books that might be helpful.

The New Organic Grower, by Eliot Coleman - Chelsea Green Publishing

Rodale's Illustrated Encyclopedia of Gardening and Landscape Techniques, Rodale Press, Emmaus PA

A GREAT web resource produced by Debbie Roos - the Extension agent for the Chatham county area.  Debbie has her finger on the pulse of sustainable ag for the entire state so be sure to get on her listserv - as she is always sending out information on workshops and other neat events. http://chatham.ces.ncsu.edu/growingsmallfarms/
webresources.html (this link will take you directly to the page
on her website that provides all kinds of additional resources.
If you browse just her website though - there is a tremendous amount of information right there too...

The Center for Environmental Farming Systems (CEFS) is a great resource for work shops and seminars on sustainable ag.
in general. http://www.cefs.ncsu.edu/

The Carolina Farm Stewardship is a wonderful resource for information and outreach.  (Before the USDA took over the organic certification - the CFSA WAS the certification entity for NC...  Now they're primary function is information resource and support for sustainable ag.) http://www.carolinafarmstewards.org/

THIS is my all time favorite resource for information...  I subscribed to their magazine (Organic Gardening) for almost 25 years...  It was what really inspired me to follow by bliss.  http://www.rodaleinstitute.org/new_farm