I think that organic agriculture ideally is a sustainable practice. However, some times it is true and some times it is far to reach the sustainability (like conventional agriculture). Here, I want to discuss the issues and boundaries of organic agriculture. Finally, I will like to focus in the relatively new tendency in agriculture systems: “Sustainable Agriculture”.

That sounds like a great topic. The debate is still raging whether we can feed humanity on organic agriculture. I have some literature on this, too and we will have a section on agriculture in the class.

Thanks for the reference Diego it will definitely be useful in my introduction. The paper I was telling you about refers to plant productivity and diversity. It relates to this idea of intercropping. That is, if you increase the number of plant species in an agricultural system with low nutrient input primary production increases. I think this relates to the capture of sunlight, since a diversity of plant shapes and sizes more efficiently fills the available space to capture sunlight. But as you know, with the correct set of species you can also increase N2 fixation which benefits not only the species fixing it, but also nearby plants or those planted in succession. See NAEEM et al. 1994. DECLINING BIODIVERSITY CAN ALTER THE PERFORMANCE OF ECOSYSTEMS. NATURE 368 (6473) 734-737. A more recent study showed related effects, but they used different genotypes of the same species of plant (Crutsinger et al. 2006. Plant genotypic diversity predicts community structure and governs an ecosystem process. SCIENCE, 313 (5789), pp. 966-968).

Good questions. You will find that there is much writing on these issues in scientific journals that will probably give you more in depth information than the online sources you cited. To me the most interesting question is what we discussed in class: how much more land do we need for a sustainable organic agriculture compared to the unsustainable conventional fossil fuel driven agriculture we use right now? If it is much more, maybe too much more, what could we do to make it less? Less meat would certainly be a huge first step. Common gardens could be another. All these question would make great opportunities to pull some numbers together and do some big thinking with "back of the envelope" calculations (that means rough or approximated calculations that still give us a good idea of the bigger picture and realism of alternative approaches).

Your outline looks very promising. I'm already really curious to learn about several questions you are posing. Again, I'm always pretty interested in numbers - so whenever you come across numbers, such as yield per area, and how they compare among different agricultural systems and over time, take note and try to incorporate them for a compelling story. Really interesting stuff - after all we all need to eat and agriculture uses large amounts of land!

That's a great accumulation of material. You did a very good job of pulling numbers together so that we're not only left to talk about the virtues and eventual inevitability of organic agriculture (as fossil fuels run out) but also can see right now what consequences on food supply, climate change, biodiversity etc it would have to promote organic agriculture.

Ultimately I hope that you will have some cross links to Christina's (ground water pollution), Sumantra's (evapotranspiration), Jeremy's (biodiversity), Seth's (biofuels), and Chip's (climate change) documents.

As came out in the discussion, I'm really interested in why subsidies are used the way they are used today (ie to exclusively support the most intense industrial agriculture) and what it would take to change that. But that's a very complicated topic - an assignment in itself so I don't expect you to cover that in any great detail. But mentioning it in the conclusion would be great.

This is very nice work, Diego. I'm impressed. You only need to polish this up a little bit over the next week and you are all set. The only point you could strengthen a bit is the outlook and conclusion. You clearly showed what is needed to feed the world in a sustainable way. However, besides demanding that the governments implement these solutions, you don't offer much in terms of how to get the things done. Not that I expect you to solve this question - it's a tremendously difficult one - but you could maybe add a couple of other approaches that are already being used such as organic certifications. Such certification allows consumers to "vote" for sustainable agriculture with their money separate from government regulations.

I am not sure if you already have this as a refernce or not but the National Research Council has a book on alternative farming that includes 11 case studies that describe in detail the practices and performance of alternative farming. The online link, which includes most pages is:
http://books.google.com/books?id=HZpG2jefbzQC&dq=sustainable+agriculture&printsec=frontcover&source=in&hl=en&ei=w4S2SYqoBZ-atweDvN2-CQ&sa=X&oi=book_result&resnum=13&ct=result#PPP1,M1