How to read organic agriculture debates

The journal Nature (link may be gated) recently had an interesting meta-analysis -- or quantitative literature review -- about yields from organic agriculture.

The accompanying summary says, "conventional agriculture gives higher yields under most situations."  This is probably true.

Yet, even environmentalists are overreacting to the study.  A recent article by Bryan Walsh at Time Magazine's Ecocentric blog is titled, "Why Organic Agriculture May Not Be So Sustainable."

The evidence Walsh presents fails to support the headline, though the article does begin with two good points:

• Organic agriculture commonly has a yield penalty per unit of land (see the Nature article above).
• Environmentalists should care about efficiency.  Getting more output for lower resource cost is good environmentalism.

Mostly, though, Walsh repeats common overstatements of the advantages of conventional agriculture.  

Conventional industrial agriculture has become incredibly efficient on a simple land to food basis. Thanks to fertilizers, mechanization and irrigation, the each American farmer feeds over 155 people worldwide. 

Environmentalists discussing conventional agriculture should remember several key themes:

• Not all productive technology improves the environment.  Many technologies used in conventional agriculture are designed to save labor, not to save land.  In Walsh's quote above, huge mechanized combines elevate the number of people fed per American farmer, but they make little difference to yields per unit of land (the key environmental issue addressed by the Nature study).  From one sentence to the next, Walsh conflates food per American farmer with efficiency "on a simple land to food basis."
• Yield is not the same as efficiency.  Organic agriculture commonly requires a tradeoff, giving up some yield and undertaking some additional labor and management cost in order to gain something of value for the producer and for the environment.  Advocates for organic agriculture say the tradeoff is efficient -- getting the most output for the lowest resource cost when all environmental costs are accounted.  Walsh's first sentence boasts of the "efficiency" of industrial agriculture, but the following argument fails to support the boast.
• Producing more grain is not the same as feeding the world.  Any time the high yields of U.S. corn production are mentioned, it should be noted that most U.S. corn goes to ethanol and animal feed.  Walsh seems to think that Iowa corn farmers do well at feeding the most people possible for the least land, which is false.  If the goal is to feed the world, then most of the calories produced in Iowa corn fields are squandered already, and this loss matters more than the organic yield penalty matters.

Most hard-headed well-grounded advocates for organic agriculture already understand the yield tradeoffs, and they already value efficiency.  For example, Rodale studies over the years have always claimed that lower chemical input costs offset modest yield penalties -- a claim that may be nearly consistent the new Nature study.

One sometimes meets beginning organic farmers who are dismissive of yields and efficiency.  But one never meets an organic farmer who has been in business for five years and remains dismissive of yields and efficiency.

There is one lesson in this whole argument for organic advocates.  It is important to speak plainly about yield penalties and about efficiency.  Perhaps Walsh was not sufficiently familiar with hard-headed well-grounded research on organic practices, but instead may have been reading some excessively optimistic pro-organic public relations.  Then, when the PR message was contradicted by the Nature study, Walsh overreacted.  It is best all around to state the relative advantages of environmentally sound production practices plainly and precisely from the start.