In the last year or so the claim that organic farming methods can feed the world has come up several times. The regular news media are not enabling their readers properly assess the credibility of such claims when they emerge because they are failing to ask ask the most relevant questions.
So that regular journalists and readers will be better prepared next time the “organic farm yields match conventional tech” claim surfaces in the media, the Pundit poses some of those necessary questions below.
The bottom line is this.
It’s the performance of the whole farming system over time that is most relevant, not just the output of any one farm field in one particular harvest season. We could call this relevant practical performance factor “farm system yield”, as opposed to “single season unadjusted yield”.
Some key questions about the “organic crop yield” issue to help focus on system performance are:
1. Where does the manure come from? This seems a simple question but many people don’t get the point of asking it. Massive amounts of manure are needed to feed the world using organic farming. Green, brown, greenish brown or whatever, the manure colour is not important– but the accounting for the nitrogen content of this manure is really crucial.
The point of this question is what did the cows, pigs and chickens eat, and where did that forage or feed get its nitrogen from? A diagram at the top shows the flow of nitrogen in the food chain, and we can see that animals get their feed from crops and pastures. Those harvested or grazed crops in turn get their nitrogen from the atmosphere.
Nowadays extraction of the world’s farm nitrogen from the atmosphere relies heavily on the synthetic fertiliser industry. Synthetic fertilisers supply near 50 percent of all the nitrogen appearing in the worlds crops (Smil 2001). Food crop nitrogen is thus ultimately largely extracted from the atmosphere in highly efficient fertiliser factories. These factories have a tiny land area footprint.
2. Does the quoted organic farm food yield factor in the land area allocated to green manure, and there any nitrogen subsidies provided indirectly by synthetic fertilisers to organic operations via animal manure inputs?
Claims are often made (e.g. The Rodale studies) that organic farms match the yield of farms using synthetic fertilisers. But they leave out the land or time needed to make organic fertiliser. Non-organic farms don’t have to make this correction because synthetic fertiliser factories have extremely small land footprints (see Smil 2001 for extensive discussion).
A holistic approach is necessary to work out meaningful food crop yield yields. If an organic farm uses green manure from a cover crop as a form of fertiliser, the land used to grow that green manure crop has to be added to the land used for the food crop itself to work out the effective crop yield at a farm scale. If the farm uses crop rotation, operating say, with a food crop every other season, effective yields are halved. (One food harvest every two seasons). Thus to simply match alternative farming approaches in raw yield is not enough. It’s the actual overall holistic or system performance for the whole farm area several season’s that is the key metric for evaluation. Forgetting about the land area used to produce biological nitrogen capture is another opportunity for dodgy yield accounting.
3. Can China do it?
In the 40s, 50s, and 60s China used to farm organically.
There is a tragic story about how China transitioned to food security in the 1970s and away from an “organic” farming system– outlined well in Smil’s 2001, but in superb detail elsewhere, which needs to be set against and claim that organic farming is practically useful on a large scale. The Pundit will return to this story in a later post, but for the moment he will just present another of Vaclav Smil’s figures to make the point:
|From V. Smil 2001.|
“Organic” methods have a minuscule current usefulness in meeting China’s food security needs because they meet only a tiny fraction of the total nitrogen nutrient needs.
Out of respect for the millions of Chinese who tragically and unnecessarily died learning the important lessons about food security encapsulated by Smil’s Figure 7.5, we should carefully and searchingly scrutinise the farm area footprints coming from the proposals of organic farming enthusiasts when they start claiming their approach is the way to feed the world.
Global farmland’s environment land area footprints really matter when we need to feed near ten billion in 2050. That’s billions of footprints.
(Source – http://gmopundit.blogspot.com.au/2014/12/can-organic-farming-feed-world-its.html?m=1)