I have mentioned agricultural twitter discussions before (see HerdySheperd on twitter)
In case you have been wondering about other agricultural discussions twitter, you can follow the #AgChatOz hashtag and the @agchatoz twitter stream. There is some background information about it too.
This has been developing over time - see Farmers on twitter: hashtags over harvesters. Meat and livestock Australia is giving advice how to use twitter (and it is a very useful introduction), and there has been discussion about Landline on twitter,
There are other accounts you may be interested in such as ABC Rural and many other hashtags and even more.
I think it is exciting that farmers, like librarians can connect all around the world to areas of common interest as well as areas of specialist interest.