[avirajmehra (OP)]

Can Organic farming feed millions of people around the world? 

[SteveFish]

Organic farming may have to feed billions unless some other new method for replacing fertilizers, currently made from fossil fuels, becomes available.

[CliffordK]

There are methods of organic farming to use "Nitrogen Fixing" plants as cover crops.

Some studies have shown that relay planting of cover crops, then tilling them in can be as effective as using inorganic fertilizers. 

I wouldn't be surprised if someone attempts to add nitrogen fixing capabilities to some of our core grain crops.  However, I would certainly encourage care, as our atmospheric oxygen/nitrogen balance is critical to all life on the planet.

Managing soil phosphates may be more difficult, and would require maintaining a natural cycle with waste returning to the fields. 

Human sewage often has additional contaminants that we don't wish to concentrate.

[tishakothari]

Organic farming can be completely taken over only once we get effective ways to curb the pests. At the moment I guess it would be ideal to use a bit of both. We can use some pesticides which are not harmful and can be used well in combination with organic techniques.

Any idea which pesticides can be used?

[SteveFish]

One of the big secrets of large corporate agriculture is that their ways of farming and the giant monocultures they produce are actually making their own pest problems much much worse, so pest problems in organic agriculture, though present, aren't as important. There is also something called integrated pest management that I think is a combination of organic and new scientific methods. Check it out.

EDIT- I just remembered Polyface farm. The owner, William Salatin, has perfected methods for growing meat and eggs with animal food grown on the farm. He writes, teaches, and lectures about organic techniques, and what he is able to get out of a small farm is impressive-- http://www.polyfacefarms.com/default.aspx