Now that Farmer’s market season has begun, you will find organic crops for sale all over the place. We love browsing through these markets, smelling the fresh crops and talking with the actual farmers that grew them.

There is no question that organic farmers are sincere and hardworking people who want to produce the very best food they can. From the supermarket manager’s view, the markups on organic produce may well be quite a bit more, making them significantly more profitable. You can find a nice discussion of organic markups here in Whole Foods Markup.

But why buy organic foods? Are there any good reasons? The original idea was to avoid pesticides that may be harmful, and enrich the soil with compost instead of synthetic fertilizers.

Pesticide residues

But in fact, the amount of pesticides found on conventional crops (even on the Environmental Working Group’s “Dirty Dozen”) is orders of magnitude lower than the established safety levels.

In a 2011 peer-reviewed paper by Winter and Katz, they analyzed  the same USDA data used by the EWG and compared it to the “chronic reference threshold,” the estimate of the amount of a chemical a person could be exposed to on a daily basis throughout a person’s lifetime without any appreciable risk.

All of the vegetables in this dirty dozen had residues thousands of times lower than this threshold, as we noted in our article Pesticide Residues and Organic Crops.

And furthermore, this same USDA data shows the 23% of organic vegetables had detectable, but equally low residues of these same pesticides.

Botanical pesticides

But these numbers do not even measure the botanical pesticides used on organic crops, which are allowed because they are of “natural” origin, not because they are safer. In fact some of the pesticides sprayed on organic crops are worse for you and the environment.

Rotenone is one of the worst, is toxic to fish and can induce Parkinson’s disease. Not all organic farmers spray these toxic, but approved pesticides, but neither do all conventional farmers. Christie Wilcox discusses this in Scientific American’s Mythbusting 101 blog.

But the most persuasive reasons not to choose organic crops are found in plant pathologist Steve Savage’s article Six Reasons why Organic is not the most Environmentally Friendly Way to Farm.

Organic foods are nutritionally identical

Studies by scientists at Stanford and earlier by Dangour, et. al. have concluded that there is no significant nutritional difference between organic and conventional production methods. There are significant variations in nutrition depending on climate and soil conditions much more than on the farming techniques used.

Prescientific standards

Savage notes that much of what became our Organic Standards were codified years ago before we knew as much as we do now about toxicology, the environment and climate studies. He terms some of these regulations “pre-scientific.” And even when there was an opportunity to update them the organic businesses resisted it.

For example, the only approved organic fungicides are copper-based, are quite toxic to aquatic invertebrates, and have to be reapplied frequently. But today there are modern, synthetic fungicides that are considerably less toxic and break down into more innocuous materials. Unfortunately these safer fungicides are not allowed by these pre-scientific organic standards.

On composting

One of Savage’s major objections is to the use of manure for fertilization, because it has to be composted to do away with toxic microbes, and this composting process produces a very high level of greenhouse gases. In fact, more greenhouses gases are generated by composting than by manufacturing fertilizer from methane and atmospheric nitrogen. This is discussed in this Applied Mythology article.

Let’s consider one acre of farm land. Farmers typically apply about 5 tons of composted manure per acre. The greenhouse gases generated during composting are equivalent to the carbon footprint of manufacturing urea fertilizer for 12.9 acres, or counting all inputs the equivalent of the carbon footprint for producing 5.7 acres of corn. Clearly this is not scalable.

It is possible to prevent these greenhouse gases during compost fermentation by using an anaerobic digester, but these are quite expensive and not in general use, although some very large farms have begun using them.

Another interesting issue regarding compost is highlighted in the article No, Cows Don’t Make Fertilizer. Cows, of course, do not produce nitrogen. The nitrogen comes from the plants they eat, and these may well have been produced by conventional fertilization. This is permitted by organic standards, as explained in this U Conn Extension article.

In other words, cows are being used to “launder” conventionally fertilized grasses and their manure used to reclaim this nitrogen and call it organic! In the process, not only are substantial greenhouse gases generated, but more phosphorus is generated than the plants can absorb, leading to phosphate runoff.

Plants, of course, absorb the same molecules of nutrients regardless of whether they come from compost or from nitrogen fertilizers, but it is not so easy to distribute fertilizer in drip irrigation to exactly where it is needed if the fertilizer source is compost as opposed to soluble fertilizers. And the irony is that work is going on to develop ways to use wind power to create the nitrate fertilizers in a completely green way, but these more efficient fertilizers are not permitted on organic crops. (See Moving Towards Fossil-Energy-Independent Fertilizer.)

No-till farming

One of the most promising farming innovations in recent years is no-till farming, where the soil is not disturbed while the crops are growing and weeds are removed using low-impact herbicides like Roundup (glyphosate). Not only does no-till limit erosion and nutrient movement into water, it saves energy and reduces farming’s carbon footprint.

However, no-till is difficult for organic farmers to implement because there really are no effective organic herbicides that can be used. And while cover crops are used by organic farmers, they have greater weed control problems than conventional farmers do and use tilling instead.

Productivity of organic farms

Organic farms do not have the efficiency of conventional farms because they are limited in their choice of fertilizers and herbicides as well as in pest control. The chart shown in the slide show (Figure 1)  is reproduced from the article Today’s Organic, Yesterday’s Yields, with the data drawn from USDA 2008 crop yield data. In general, the data show that organic farms have yields no better than 80% of those of conventional farms, and as low as 40% for organic carrots.

This, of course, makes them much more expensive to grow, and this cost is passed on to the consumer with no actual benefit. A similar conclusion is drawn in this 2011 paper in Nature: Comparing the Yields in Organic and Conventional Agriculture.

While the organic advocate publisher Rodale has created a report suggesting that organic farming techniques have higher yields, they admit that they have never published this work in any peer-reviewed journal.

Organic food is a niche market

The total US organic acreage is only about 0.5% of the current US cropland, and growth has slowed. Even if it continued at the rate before 2008, Savage projects that organic cropland would only be about 3% by 2050, and in fact in recent years there has been no real growth in organic croplands. This is shown in Figure 2 of the slide show.

Organic foods do not contain GMOs

This is true, but this is actually backwards, in that the entire disinformation campaign against GMO crops is led and financed by the organic food industry, who wants to keep this distinction in order to maintain their high price point. As we have noted time and time again, GMO crops are nutritionally identical and have never been shown to cause any harm. Every major scientific organization worldwide has come to the conclusion that they are identical to conventional crops and harmless.

Conclusions

Much as it may disappoint organic partisans and idealists, there just aren’t any good reasons to buy organic crops over conventional ones.

• They are nutritionally identical.
• Conventional crops have pesticide levels well below any possible danger level even if you ate them daily, and the pesticides used on organic crops are actually more dangerous.
• Organic fungicides are considerably more dangerous.
• Organic crops have a more than 5 times larger carbon footprint because of greenhouse gases released by composting and because of the need to till organic crops.
• Organic crops are more expensive both because of lower productivity and supermarket price gouging.

Organic foods are not exactly a “scam,” but they have no real benefits to justify their high price. We recommend buying fresh foods from local farmers when you can, because you can at least ask how they were grown. And they will probably taste better, too.

This article was originally published on Examiner.com in May, 2013.

• Biotechnology
• Food science