Can somebody explain crop rotation

[dtw]

I've seen crop rotation mentioned a few times.
Can somebody explain why this is necessary (for an almost complete novice).
Also, some popular crops which I can use.
I am mainly planting chillies, sweetcorn, onions, pak choi, various beans and some herbs this year, I didn't grow a lot last year, chillies, a few marrows a pumpkin and beans.

[dtw]

[flossie]

Hope this link works - have not posted a link from the site before...

http://www.allotments4all.co.uk/joomla/smf/index.php?topic=14631.0

If not, try a site search on rotation.

[dtw]

That worked, Thanks.  :D

[Tee Gee]

And this is my version; http://tinyurl.com/ytwqf9

[okra]

I use a 4 crop rotation - its the same as the 3 crop ritation system but I just plant spuds in one area

[cornykev]

Likewise. ;D