It sounds like the conservationist’s dream. But a return to traditional mixed farming ways could pay off for farmers too.
Tim Radford, a founding editor of Climate News Network, worked for The Guardian for 32 years, for most of that time as science editor. He has been covering climate change since 1988
Cross-posted from Climate News Network
Once again, researchers have shown that it should be possible to feed the human race and leave enough space for the rest of creation, simply by going back to centuries-old mixed farming practices.
That would mean an end to highly intensively-farmed landscapes composed of vast fields that were home to just one crop, and a return to a number of once-traditional husbandry methods. It sounds counter-intuitive, but European researchers are convinced that it could be good value.
They report in the journal Science Advances that they looked at more than 5,000 studies that made more than 40,000 comparisons between what they term diversified and simplified agriculture.
And they found that crop yield in general either kept to the same level or even increased when farmers adopted what they called diversified practices of the kind that sustained subsistence farmers for many centuries.
These include intercropping − different crops side by side − and multiple crops in rotation, strips of flowers to encourage pollinating insects, lower levels of disturbance of the soil and hedges, and forested shelter belts to encourage wildlife alongside farmland.
The payoff? Better ecosystem services such as pollination, the regulation of crop pests by natural enemies, a more efficient turnover of nutrients, higher water quality, and in many cases better storage of carbon in ways that could mitigate climate change.
This, of course, is not how big agribusiness delivers much of the world’s food.
“The trend is that we are simplifying major cropping systems worldwide,” said Giovanni Tamburini, an ecologist at the Swedish University of Agricultural Sciences in Uppsala, who led the study.
“We grow monoculture on enlarged fields in homogenised landscapes. According to our study, diversification can reverse the negative impacts that we observe in simplified forms of cropping on the environment and on production itself.”
It’s an old argument. Is it better for a farmer to invest all in one vast crop of maize or wheat or soy, regularly nourished by commercial fertilisers, routinely sprayed to suppress pests, moulds and mildews, with the land ploughed and harrowed after harvest for the next crop, and always at risk of frost or flood, locust swarms, drought or blight?
Or would it be better in the long run for the farmer to spread the risk by changing and multiplying the crops, and to rely more on undisturbed soils and local habitats for birds and insects that would demolish some of the pests (and of course take some of the crop)?
Researchers have repeatedly argued that both to contain climate change and to preserve the natural world from which all human nourishment and almost all human wealth ultimately derive, farming practices must change, and so must human appetite. The argument remains: what is the best way to set about change down on the farm itself?
There have already been a large number of studies of this question. There have also been meta-analyses, or studies of collected studies. Dr Tamburini and his colleagues identified 41,946 comparisons embedded in 5,160 original studies. They also found 98 meta-analyses. And they took a fresh look at the whole lot to identify what could be win-win, trade-off and lose-lose outcomes.
They found that diversification is better for biodiversity, pollination, pest control, nutrient cycling, soil fertility and water regulation at least 63% of the time. “Most often, diversification practices resulted in win-win support of services and crop yields,” they report.
“Widespread adoption of diversification practices shows promise to contribute to biodiversity conservation and food security from local to global scales.”