Diversity vs production?

There is a lot of new ‘hype’ stating that biodiversity can increase the stability of small-scale agricultural systems, but has anyone evaluated the production side of these systems? Can anyone explain to me if diversifying the farm is actually financially beneficial in the short or long term? I come from a production farming background and am now working overseas teaching famers in Africa. I don’t what to teach farmers practices that are not sustainable, especially with the more prolonged droughts they have been experiencing. But I also don’t what to teach them practices that are not economically profitable for them to get started in. I don’t want them to just sustain themselves, but also provide them with the ability to move beyond subsistence and see farming as income-generating.

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I think these are important questions. The short answer is yes, someone has evaluated the production side of diversified systems, and no, diversification does not always lead to increased production… only 32% of the time according to this meta-study. As someone also working with small-scale farmers in Africa, I still very much believe in the benefits of diversification, for several reasons:

  1. Yes, in the above study, diversification led to no change or a reduction in yields in 68% of cases. However, as farmers we are relatively new to diversification. We are still learning how to do it right. It is normal that we should fail in a lot of attempts. In nature, it is indisputable that enormous yield benefits are achievable in mixed-species meadows, forests, etc… Learning which species “play nice” together on the farm will take some time and practice. But ultimately, I’m convinced that it will be financially beneficial, especially so for small-scale farmers.

  2. Studies like those above are usually only measuring production in a single season. What makes well-designed diverse farm systems intriguing is that they essentially produce two sets of harvests: something to sell this year, and a stronger soil and ecosystem to produce a crops in the coming years. For example, introducing diverse (6-12 species) cover crop mixes into a corn growing system has allowed some farmers in North Dakota to not only increase production this year (by ~10%), but improve the soil to the extent that next year they can reduce their use of fertilizers by 33%-100%. There are farmers cropping corn on the same land every year without ANY inputs, including compost - because of diverse cover crops. A farmer in California crops 6 consecutive crops of vegetables without any inputs (again, including compost!) by rotating that field with a year of diverse pasture with chickens and sheep. Even if production of a single season were decreased somewhat in systems like these, it could be worth it if it means more sustainable, low-input production in the long term.

  3. We have to be careful about evaluating production as divorced from stability, or health, or any of a number of other measures. Production without stability, or without health, is not a long-term benefit, especially for small-scale farmers with limited savings. A small but guaranteed yield is more helpful than a large but unsure one to risk-averse farmers. And that is one of the ways that diversity brings stability: by growing multiple crops, your chances of having at lease one marketable harvest are increased.

  4. A lot of benefits of diversified systems lie not in increased yields, but in reduced costs. Hedgerows take time and effort to plant and often offer no marketable yield. So are they worth it? They might be once you add up the savings in artificial windbreaks, pesticides, thievery, firewood, herbs, and fruits & berries for the kids’ nutrition.

Diversification does not necessarily lead to financial gain in the short OR long term, just like having multiple people in a house doesn’t automatically make a family. But there are plenty of examples (like those in the links above) that show that not only health and stability, but also sustained financial productivity are achievable through well-designed, diverse farm systems. Ultimately, though, most diversified systems, especially multi-species intercrops, are experiments at this stage. Are such experiments risks worth taking? Not necessarily for many small-scale farmers with limited financial margins. In their cases, moves toward diversity might have to be taken in small steps, like crop rotation, diverse living fences, or a well-proven intercrop like sorghum and cowpea.

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