Diversity is our strength: Planting a mixture of crops can benefit the surrounding ecosystem

Insects are in trouble. That doesn’t make them special, or anything (they were always special to me), but they play a vast number of important roles in our various ecosystems, including the pollination of certain plants. Knowing the people who read this blog, I’m sure you find this information to be shocking and new, especially as I’ve never written about it before.

Jokes aside, though, this is an issue that has had a lot of people worried for a long time now. A lot of blame has been placed on the heavy use of pesticides required to keep our current monoculture farming regime from completely collapsing, plus those used in more residential and recreational settings. I think that’s certainly a reasonable thing to look at, but it’s also reasonable to look at habitat destruction, as well as the just-mentioned use of monoculture farming. Poison obviously affects one’s ability to live and thrive, but so to does having one’s ecosystem fall apart (something to which we should probably pay attention).

A German research team has now provided us with yet another reason to change how we do agriculture, because it turns out that the lack of diversity that characterizes modern food production is bad for bees and other insects.

There are often too few flowering plants in agricultural landscapes, which is one reason for the decline of pollinating insects. Researchers at the University of Göttingen have now investigated how a mixture of crops of faba beans (broad beans) and wheat affects the number of pollinating insects. They found that areas of mixed crops compared with areas of single crops are visited equally often by foraging bees. Their results were published in the journal Agriculture, Ecosystems & Environment.

The researchers observed and counted foraging honeybees and wild bees in mixtures of wheat and faba bean and in pure cultures that only contained faba beans. “We had expected that the mixed crops with fewer flowers would be visited less frequently by bees for foraging than single crops,” says PhD student Felix Kirsch from the Functional Agrobiodiversity research group, University of Göttingen. “To our surprise, this was not the case.”

This could be due to several reasons. “Our mixed cultures were less dense than pure cultures, which possibly increased the visibility of the flowers. This might have attracted the similarly large number of bees to the mixed cultures,” suggests Dr Annika Haß, postdoctoral researcher in the Functional Agrobiodiversity research group. “In addition, reduced competition between the faba bean plants in mixed cultures could mean that they can invest more resources in the production of nectar and pollen to increase their attractiveness to bees,” adds Professor Wolfgang Link, head of the group for Breeding Research Faba Bean.

“Mixed cultivation of wheat and faba bean has also other advantages for crop production,” says Professor Catrin Westphal, Head of Functional Agrobiodiversity. For instance, yields per bean plant were higher in mixed crops than in pure cultures. “Cereal crops can be ecologically enhanced by adding legumes such as beans or lentils. This can make a valuable contribution to increasing the abundance of flowers on the arable land and thus counteracting pollinator decline,” concludes Haß.

Truly, it is one of the great burdens of our time that in order to save ourselves, we must make the world a better place to live in. We hear over and over again about the “Insect Apocalypse”, and now it turns out that part of changing course, means making the landscape more interesting? What’s next, cleaner air? No danger of being unhoused? It doesn’t bear thinking about.

I’m kinda worn out from working on a much less pleasant post, so I’ll just leave you with my regular reminder: Our problem is not a lack of solutions, it’s a political and economic hierarchy that actively hates the solutions that we do have. Obviously if you have the means to directly change or improve the landscape around you, then I heartily recommend doing so, but that will never be enough without real, dramatic political change.


  1. planter says

    An interesting study. Polycultures were common in non-mechanized farming systems have always been used in forage (hay) crops, but for many reasons mixed crops have not been used for grain production. Difficulty harvesting is a big issue (what do you do with a 1000 bushel bin of mixed wheat and field peas, when the buyer only wants one of them….). This is an area where technology is moving quickly to get around the logistical problems, as modern seed cleaning equipment can easily separate different seed types. Field trials that demonstrate yield and/or soil nutrient benefits greater than the cost of seed cleaning will likely get adopted fairly rapidly.

  2. says

    Yeah, there are always going to be downsides. That’s part of why I think we should be trying new thing as quickly as we can, so we have time to troubleshoot before we’re dependent on them for survival.

  3. another stewart says

    This suggests using a mixed planting of oats and field beans as a fodder crop (both are grown individually for that purpose).

  4. says

    It is nearly two decades since I spoke about this with one of my friends who was doing research on some rare butterflies around here back then. The scientists back then not only found out the problem for these butterflies – mechanized mowing of grass on an unprecedented scale – but also a solution – to leave about 10% of the meadows and gardens unmown each year and only graze there (or not even that). The farmers had no issue with it in principle – making hay on only 90% of their land was sufficient to feed the livestock and still some was left over. But they still could not implement it because in order to get subsidies, they absolutely had to mow 100% of their land every year, even though it meant that they simply are making hay for it to rot. A simple solution would be to slightly change the criteria for giving subsidies to the farmers by including a few options for proper land management and perhaps employ a tiny bit more regulatory staff to check the slightly more complicated rules and everybody would be happy. It would also help with another problem exacerbated by climate change – decreasing water retention capabilities of the meadows because the earth gets too compacted by heavy machinery and there are not enough bushes and trees to slow winds and shade the landscape.

    I have seen it work when one of my neighbors let one of his meadows completely unmown and ungrazed one year on purpose because he heard somewhere that it helps it to recover – and it did. The increase of biodiversity in that meadow was visible to even an amateur, suddenly flowers bloomed there en masse that were just a rare sight everywhere else. And the grass next year was visibly taller and healthier.

    A lot of time has passed and the issue is still not resolved. Farmers still have to mow 100% of their land twice a year, effectively destroying the landscape in the process by over-mowing the grass and over-compacting the soil. Because governments do not listen to scientists.

  5. Katydid says

    …and yet, the Tanach and the Old Testament (Leviticus) both insist it’s a god-offending sin to plant a field with two crops. So Judaism and Christianity both forbid it.

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