Comparing Organic vs. Conventional Farming: Resource Efficiency

In which ways does agriculture affect our environment and our daily lives? Read the introductory post to this series here. Part 1 explored the theme of water, part 2 focused on soil fertility, part 3 investigated biodiversity under organic vs. conventional farming systems while part 4 controversially discussed climate protection through conventional vs. organic farming. In the last post, we asked which farming systems are best prepared for climate change.

Resource efficiency

With resources becoming more and more scarce in our consumption-driven world, it’s becoming increasingly important to use resources wisely. Basically, for resources to be sustainable, they need to be renewable and used in the most efficient way possible.

Farming uses many resources, too: natural and synthetic resources.

One important agricultural resource are fertilizers, namely nitrogen fertilizers. Conventional farming depends on high inputs of synthetic nitrogen. These fertilizers are produced using fossil fuels through the so-called Haber-Bosch process. Basically, this means that conventional farming heavily depends on a non-renewable and finite source of energy for growing its crops. Organic farming does not use synthetic fertilizers.

On the other hand, organic farming aims to create closed nutrient cycles.

Mimicking nature

Ideally, closed nutrient cycles would look like this:

All the natural resources, all the nutrients that are taken away from the farm as food sold to the consumers, should eventually be returned to the farm. That’s how nature works: nothing ever gets wasted!

Whenever people did not follow nature’s example, problems started to emerge. For example, nitrogen leaching from the overuse of synthetic fertilizers is poisoning our waters, as I explained in part 1 of this series. And our dependence on finite resources, such as fossil fuels and mineral phosphorus, to grow our food, is simply not sustainable!

Another fertilizer that conventional farming depends on is phosphorus, an essential element for growing plants. In the past few decades, we have been mining phosphorus for fertilizers, but these mines will eventually be depleted. Scientists predict that “at current consumption levels, we will run out of known phosphorus reserves in around 80 years, but consumption will not stay at current levels.”

That’s a very grim scenario, but if we followed nature’s principles, it wouldn’t need to be that way!

What do organic farmers do?

Organic farmers use organic fertilizers: animal dung and compost instead of synthetic fertilizers. Conventional farmers also partly use organic fertilizers, but they use synthetic fertilizers in addition to that.

Without using synthetic fertilizers, organic farmers can never achieve the levels of yield as conventional farming. Yields are higher by 25% in average in conventional farming.

The question now is, which system is more efficient regarding the use of nitrogen and energy, two major agricultural resources? To answer that question, we will once again look at figures from a recent scientific study*.

As for inputs (= for ex. fertilizers) of both nitrogen and energy, they are much lower in organic farming. Makes sense, since organic farmers don’t use the energy-intensive synthetic nitrogen fertilizers. Consequently, due to lower yields, the nitrogen and energy output (=harvested crops) were also lower in organic farming.

The key question is: what’s the difference between input and output? Or, in other words, has anything been wasted in the process? Ideally, the difference between input and output would be zero: you take as much nitrogen away from the field as you previously put in, making sure that nothing is wasted and nothing is washed out into the groundwater. Groundwater contamination with excessive nitrogen often is a problem that damages both the environment & our health, and also is very inefficient.

In conclusion, the difference between input and output was significantly lower in the organic variants (by 40 to 70%). This means that nitrogen and energy are used more efficiently in organic than in conventional farming. And organic farms are even more efficient when you look at it from a long-term perspective. Nitrogen from organic manure gets stored in the soil and is released more slowly. This makes sure that nitrogen doesn’t leak into the groundwater as quickly and that plants get the nitrogen they need on the long-term, from a healthy soil**, rather than short-term from quickly coming, quickly going synthetic fertilizers.

Which scale was applied in the study?

This is an important question to ask. The study applied the per-area scale, meaning that input/output balances were measured per area of farmland, and not per kilo or tonne of produce. When the per-unit scale is applied, conventional farming might be more resource-efficient because yields are higher.

The discussion about this is very similar to the one we had in my article on climate protection, so have a look at the crucial point I made there. But in short, we must ask ourselves: what’s the use of an “efficient” farming system if it builds on non-renewable resources that we will run out of in a few decades? That, per se, is unsustainable.

A hopeful outlook

In summary, we can say that nitrogen and energy efficiency are better under organic management. However, the fact that the input/output balance isn’t zero even in organic farming shows us that there is more work to be done to improve farming’s efficiency. In other words, that ideal picture of closed nutrient cycles which I painted in the beginning is often not real yet.

Even if you used only animal dung and compost to fertilize your crops, you still wouldn’t be able to get back all the nutrients that you’ve taken out of the system with the harvest. What’s missing, even in organic farming?

Closing the nutrient loops

a) Leftovers from the food we bought (such as peels, leaves, fruit stones etc.) aren’t always composted. Instead, they often end up in landfills rather than on the farm! Therefore, all of our organic waste should be collected separately and composted.

b) When we digest the food we eat, we inevitably excrete some of the nutrients that we couldn’t use. To really have a closed nutrient cycle, human urine and faeces would need to be re-included as organic fertilizers (of course with pathogens previously killed off). Unfortunately, EU regulations don’t allow the use of sewage sludge on organic farms. This will have to change in the future, especially with regard to our diminishing reserves of phosphorus that’s currently being wasted on sewage!

Nevertheless, organic is clearly the more environmentally friendly way of farming compared to conventional farming. Hopefully, we will soon be able to close all nutrient cycles and farm even more efficiently and in tune with nature. Until then, let’s choose organically produced food as much as possible.

Part 7 of this series will explore whether the common idea of animals being “happier” and healthier on organic farms really is true or not.

In this blog post, I explore why we are running out of phosphorus and other essential fertilizers, how nature’s design of fertilisation looks like and how we can come back to that initial blueprint through simple, everyday actions. Stay tuned to find out more!

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*Sanders J, Hess J (eds) (2019) Leistungen des ökologischen Landbaus für Umwelt und Gesellschaft . Braunschweig: Johann Heinrich von Thünen-Institut, 364 p, Thünen Rep 65, DOI:10.3220/REP1547040572000

*organic manure promotes soil fertility in general