Monocropping is the dominant form of arable agriculture and about as far from natural as you can get — one variety of one species of plant grown in row after linear row over vast areas.
Nature is far messier. It is very rare for natural habitats to be dominated by one species and even more unusual to see one species in regimented patterns. Even where a recruitment event delivers an even aged stand of a tree species, such as often happens in Cypress pine woodland, there is usually complexity in the ground layer vegetation.
Except monoculture makes business sense. And it has been hugely successful. There are obvious economies of scale in growing the same thing over large areas, especially when the grower is supported by mechanization.
Machines allow one person to prepare, sow, fertilise, protect and harvest large areas so long as they are uniform and accessible. Operating at scale is easier and more efficient if all the plants are the same height, shape and sown at the same density. No need to shift gears or harvester attachments.
And if there is one thing humans are innately experts at, it is making life easier. Everyone loves an easy life and if making it easier also makes money then we are in heaven.
The modern extension of the monocropping approach is precision agriculture. The ability to know exactly where you are in the field down to the nearest metre coupled with electronic control systems that deliver exactly the right amount of irrigation and fertilizer to plants at exactly the right time. No need to guess.
Again such precision is of most benefit if as many variables as possible are uniform. Other than these precision inputs the farmer is only really in control of one key variable, the crop. So he plants the same one.
on the left is the natural woodland with multiple tree and herb species, on the right a wheat field sown with a single variety of wheat — Western Australia
There are a few local issues with monocultures from pollution and changes to regional climate but there really is just one major environmental issue that this type of agriculture creates…
Nature creates complexity and is resilient and stable as a result. Simplifying and making it all the same may be good for business but it brings with it a number of environmental issues. Here are a few.
Whenever there is a lot of something it creates an opportunity. On a hot day a large crowd is an opportunity for the ice cream salesman.
A field sown with a single variety of wheat is an opportunity for organisms that want to eat or live off such a mass of uniform biology. Pathogens and pests are the bane of monocropping, the biggest downside to all that efficiency.
Luckily all that precision machinery can be made to detect pests and diseases in the crop and deliver appropriate protection. But even with protection monocultures are always more at risk from invasion by pests and weeds than natural vegetation.
Sometimes protection causes problems. Runoff from pesticides and herbicides can be a major environmental issue locally, although as these inputs have become more expensive so farmers have become less profligate with them and so pollution events are not as common as they were in the past.
Continuous cropping of the same plant also mines the nutrients that that plant needs. And whilst these can be replaced with the right fertilizers, when this happens there is now a dependency. Without inputs yield declines, often drastically.
Crop yield is no longer a product of natural capital. It is as if the field has become a greenhouse and made production vulnerable in the process.
This risk is far more important than is realized. Food supply is much less stable than we would like unless we accept that we are moving away from natural capital to an input system and invest to mitigate the risks of this shift.
This is not strictly an environmental issue because the environment is something of a bystander. The issue is food security.
What does happen with monocropping and other types of industrial agriculture is that the environment is simplified. Where there were grasslands, woodlands or forests with many thousands of different species combining to create complex habitats now sit vast fields of sameness.
This affects local climate, contributes to biodiversity loss and simplifies the landscape — making it all the same.
7 billion people need a huge amount of food and there will be at least this many people to feed everyday for another 50 years.
Food production at this scale will be impossible without monocropping. The efficiencies that big fields of single crops provide will be essential to generate enough calories for everyone.
Just like the issues with intensive and industrial agriculture some of the arable landscape will stay in a modified and simplified state [homogenized]. These fields will be vulnerable to degradation from nutrient mining and the loss of soil carbon and the crops on them will be vulnerable to pests and disease.
If we are smart there is knowledge to be had from subsistence agriculture — production characterized by many different crop types from a variety of structural plant forms from trees to legumes. For the subsistence farmer dependent on his crops to feed himself and his family, a single crop is useless. A diversity of food types gives his diet balance and continuity through the year.
More importantly he has a production system that mimics nature with structural layers and multiple plant species. This in turn creates a more complex soil ecosystem thanks to varied plant inputs [leaves, roots and twigs] that helps maintain soil carbon levels.
Pragmatic solution is for monocultures where we have to and more layered systems such as agroforestry, alley cropping and pasture cropping as much as possible.
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