Agricultural diversity, good for farmers, us and the biosphere

A recent study

48 years after Sholto-Douglas and Robert Hart wrote Forest Farming: Towards a Solution to Problems of World Hunger and Conservation and 46 years after Mollison and Holmgren published Permaculture 1 this study shows that they were right. Monoculture bad, polyculture good.

An analysis of 2,655 farms on five continents no less so quite a big database. The study showed that polycultural farms can increase the amount of food that a farm produces, improve soil health and reduce the farm’s negative impacts on the environment. On top of all that good stuff the study showed that diverse farms are more resilient than monoculture ones. They can bounce back better, sorry about the alliteration I went a bit Boris there, and recover faster from different stresses such as a drought period. A particular delight coming from the study was that another advantage of agricultural diversity is that a farmer can also produce a bit to eat for themselves and their family! If you run or live on a monocultural farm and eat some of your produce then your diet is going to be pretty boring.

Farms around the world have been demonstrating for years that the thrust towards monocultures was wrong-headed and that farms with diverse activities aren’t some sort of primitive form of farming that need to be brushed away and replaced with mega-farms. It’s these extensive, highly mechanised, utterly dependant on fossil fuels and synthetic chemical farms that are the aberration. They only survive because they are massively financially supported by governments, they keep going because we keep pumping oil and they continue to destroy the environment because we accept industrial agriculture.

I’m on a train as I write this and we travel past field after field all glowing yellow and all producing Brassica napus, oil seed rape. Encouraged by the EU in order that northern Europe be self-sufficient in oil this type of cabbage plant covers 1.5 million hectares of France, total yields of oil are around 1,9 million tonnes. Walnut orchards cover around 20,117 hectares and if all the nuts were pressed for oil it would produce around 24,000 tonnes of oil. If walnut orchards covered the same area as rapeseed production then the quantity of walnut oil would be around 1.8 million tonnes.

After harvest rapeseed is followed by a second crop, walnuts however can be intercropped. This study shows that this is a viable solution and increases farm revenues “indicate that growing walnut trees and crops in the intercropped system is more productive than growing them separately.” The study didn’t include practices such as polarding to allow more light to the understorey crop nor the eventual profit from walnut timber. Another, and major factor, not within the remit of the study is the fact that rape fields must be cultivated and sown each year and this incurs a major financial and ecological cost, walnut trees need some maintenance but the costs are orders of magnitude less than with an arable field put to oil seed rape. Undercropping also encourages the trees to put down deeper roots which makes them less vulnerable to drought.

Journal of Agroforestry and Environment

If we add livestock into the equation then animals can be pastured in a walnut orchard, they manure the trees and reduce competition from the grass. This takes us back to the original article which is basically presenting the advantages of mixed farming and what, today, we call agro-sylvopasturalism which is basically an agroforestry system with animals rotated through before and after arable alley crops. What we see here is a much more sophisticated, productive and resilient system when compared to extensive mechanised production.

As a final note we have been reducing the diversity of our diets over centuries, this is not an approach which is health positive. Lack of dietary diversity means, for example, a lack of diversity in the gut and mouth microbiomes. This leads to less good health outcomes in general and more dental caries. In Permaculture we contend that health outcomes should be considered when we are calculating yields. Any form of food production should aim to provide the highest level of nutrition and the best health outcomes for the consumers, fixating on quantity isn’t good enough. ‘I am what I eat’ as we say, poor health is a burden for the individual and a financial cost to the local or national health system. Neither are counted in today’s figures on food production when they should be.