Life

Success through Diversity: Why mixtures produce more stable yields than monocultures

Arabidopsis thalania seedlings
Arabidopsis thalania seedlings. Photo: Safflle/Wikipedia.

There’s a paper published through Open Access this month that highlights the benefits of diversity in growing crops, but with a new angle. Diversity as a way of improving pest control is widely accepted, but the paper by Criessen, Jorgenson and Brown shows that diversity can produce more stability in yields too. As the title: “Stabilization of yield in plant genotype mixtures through compensation rather than complementation” suggests, the key factor is compensation.

What Criessen et al. set out to study is if mixtures of genotypes in a crop could give it better ecological stability by increasing the communal resistance. That is that overall yield would stay the same, though individual plants themselves could be hit hard or flourish under changes. The mechanism is called compensation and helpfully for people like me, that explain in clear terms what they mean.

Compensation happens when success of one plant makes up for the relative failure of others. The puts the plants in competition with each other in contrast to Complementation, which is where one set of plants may be after one thing and another set after another so that the demands of the two don’t conflict. Finally there are facultive interactions where a plant does much better if there’s another plant of a different type there. They don’t merely tolerate each other, they aid each other.

How do you test if mixed crops can compensate for each other? Criessen et al. used Arabidopsis. It’s basically the botanists’ equivalent of the lab mouse or fruit fly and now it seems it can be used to test crop yields in mixtures.

The advantage of using Arabidopsis for this kind of experiment is that it is so well known that it’s possible to ask very specific questions in experiments. Criessen et al didn’t simply measure yields of seeds, they were able to examine above-soil and sub-soil competition between plants. It’s also a lot easier to control variables in seed trays than it is outdoors.

The results were that some monocultures produced higher yields than mixed trays, but the mixtures were not far off is terms of productivity. They were also consistently producing a good crop of seeds.

Somewhere like the Agricultural Biodiversity Weblog could give you plenty of other reasons for promoting biodiversity. It’ll be interesting to see if Arabidopsis experiments can add something new to ongiong research and also see what can move out of the lab and into the field.

Image

Arabidopsis thalania seedlings by Safflle/Wikipedia

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