Organic Agriculture Yields Fall Short
17 April 2012 Is 80% good enough to feed the world?
It’s often the subject of impassioned debates – whether organic agriculture can feed 9 billion people – but a new study shows that its yields still fall far short compared with conventional agriculture.
In an interview with Farm Chemicals International, Tomek de Ponti shed light on the comprehensive study he led, which was recently published in the academic journal Agricultural Systems. His dataset includes 362 published organic-conventional comparative crop yields from 43 countries, and reveals that organic yields of individual crops are on average 80% of conventional yields. He notes that variation is significant, and the organic yield gap differs widely between crop groups and regions.
De Ponti says his analysis enlightened him on potential avenues of growth for crop input suppliers. He points to an example of technology being used in the Netherlands which processes human urine to create phosphate, identical in composition to commercial fertilizers.
“One of the interesting things that came out of the study is that there is that there is still quite a scope for increasing the nutrient supply to crops in ways that comply with organic standards, largely related to creating better nutrient cycles. Personally, I think these are very interesting new avenues for [the crop input market] to access new markets and adapt to a changing world,” he says.
Of all the regions encompassed in the study, Northern Europe exhibited the widest gap: organic yields average just 70% compared with conventional agriculture. De Ponti says this case served to at least partially prove his hypothesis, which was that the organic–conventional yield gap increases as conventional yields increase.
In other words, the closer conventional agriculture gets to the potential or water-limited yield level, the larger the yield gap will be between organic and conventional systems. So, the yield gap depends on the region and crop type: regions with more intensive, high-yielding production systems – such as in Northwestern Europe – as well as regions with tropical climates, and crops more susceptible to pests and diseases are all likely to have a bigger organic yield gap.
“If conventional yields are optimized then it’s harder, but not necessarily impossible, for organic to keep up, because it is being compared to an almost ideal system in terms of currently attainable yields,” he explains. “Organic isn’t able to keep up in terms of soil fertility, crop nutrients, and pests and diseases become more limiting.”
Contrary to what might be expected, crops which showed the largest yield gap were not always among those that are most susceptible to pests and diseases – for example, barley (69%) and flax seed (65%). “Interestingly, the crop which showed the clearest and statistically most significant relationship between the yield gap and the conventional yield level was soybean, even though this crop does not depend on fertilizer nitrogen,” de Ponti writes.
The analysis was conducted at field and crop level. Since maintaining soil fertility is generally a greater challenge for organic methods, the study hypothesized that at higher system levels, yield gaps of organic agriculture may be larger than 20%.
De Ponti says reactions to the study have been generally positive from both proponents and contestants of organic, although some organic advocates also stressed that differences in the environmental impact of both systems should be included in such an analysis. “In the process of writing our publication, we already noticed that it’s sometimes more of an ideological than a facts-based discussion. It’s a sensitive topic. For this reason we have kept to naming the facts.”
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