Sustainable vs Organic

What is the nexus between sustainability and organic farming? Is sustainable = organic?
To answer this, follow this format:
Part 1
Explain the Sustainable agriculture: how does it work, what does it do?
Part 2
What is the problem that the Sustainable agriculture addresses?
Part 3
What is the current stated of business and/or consumer adoption of the Sustainable agriculture?
Part 4
What are some of the challenges and barriers to adoption of the Sustainable agriculture, and how might those challenge be addressed?
Part 5
What are the social benefit and risks associated with the Sustainable agriculture?