Before the arrival of big agriculture with its large tractors, complex machinery, input heavy production of mostly monoculture crops on fields the size of suburbs, farming was a family affair.
Everyone pitched in to help grow a dozen or more crops, rear livestock who ate most of the scraps and make home goods from jams and preserves to cheese and cured ham.
Such variety required crops grown in patches or sequences and livestock to eat, provide draught power, and help fertilise the fields.
Some of these crops were never intended to be harvested.
They were cover crops, green manures, trap crops, green bridges, and a variety of other multipurpose species designed to keep the soil healthy, reduce pests and weeds, and feed some of the animals who, in turn, fed nutrients back to the soil in the fields with productive crops.
Farming system researchers call these service crops because they provide regulation and support ecosystem services, which are important locally, regionally and even globally.
Before production became an energy-intensive input system, non-harvested service crops were as important a tool as the plough.
Then, almost overnight, they went out of fashion.
Agricultural census data in the US show that service crops are adopted in <5% of the total agricultural land. Data from Europe indicate that cover crops, plant residues and multi-annual plants occupy shares of 8, 7, and 8%, respectively in arable land during winter.
The benefits of service crops have not gone away.
Indeed the agricultural research community has stacked up evidence for the good they do to yields and production efficiency and why this happens—in short, carbon gains, nitrogen fixation and more resilient soil biodiversity.
Farmers know this too.
Knowing the old ways
The average age of farmers in Australia is 53 years compared to the median age of 40 for the rest of the workforce, whilst in the US and UK it is 59. These folk are old enough to remember conversations with the old blokes who farmed the old way before the fields got big and the tractors bigger. They all know the value of cover on the soil and yet they choose not to plant them.
Today’s farmers claim that service crops are costly in time and resources, especially the limited availability (and high price) of seeds of several species used as service crops in local markets.
In the cut and thrust of tight forward contracts and ever-higher input costs, the benefits to soil health are outweighed by the cash flow and resource use consequences of growing a crop with no immediate return.
The few service crops remaining are grown for fodder production. These crop species are suitable for grazing, but the plant architecture, growth habit, phenology or functional traits do not consistently deliver the ecosystem service benefits that the old-time farmers knew about without knowing the fancy jargon. The old stagers saw the benefits of deep roots, high leaf-to-stem ratios (or the opposite according to needs), symbiotic N fixation, drought resistance or high water use efficiency, short or long cycles, propensity for mycorrhizal infestations, attractiveness to pests and/or to natural enemies, competitive ability against weeds, allelopathy, and a host of other ecological traits without being able to describe any of them.
With few service crops, producers who have embraced intensification now rely on inputs to achieve what fallow land used to do—give the soil time to recover, aided by the soil biodiversity. The benefits of intensification are higher yields, short rotations that reduce the time between salable harvests, and volume. All good for a profit-orientated operation.
All is well for a while, perhaps a generation or two, until the soil is depleted and cannot hold onto the inputs or until the cost of those inputs rises higher than the returns.
Just add more land
The amount of agricultural land has increased exponentially since the start of the industrial revolution, mainly because chainsaws and tractors made it much easier to clear vegetation. The assumption is that land can be added when more production is needed.
According to UN data and independent research, the world has reached its peak agricultural land, and more land is being abandoned than is being brought into production.
Roughly 5 billion hectares might be the peak.
Not only is new land hard to find—not all land can be converted for crops or livestock—we have not noticed that some of the existing agricultural lands are already depleted and going out of production.
This means it is foolish to assume that agricultural intensification is indefinite. This is not how agriculture works because plants are still grown in soil that supports the roots and provides a medium for exchanging nutrients and water.
Soil is alive, and the living parts maintain the nutrient and energy flows. Service crops are an implicit recognition of this reality.
What sustainably FED suggests
Some farmers see service crops as an investment. They know that over time it reduces external input costs, increases productivity, and provides long-term resilience. They put effort and funds into cover crops, legume leys, fodder crops, and green manures.
Some also know why this happens.
Service crops are an opportunity to return some carbon to the soil. Carbon is the essential energy source, structural support, and matrix for nutrient and water exchange in soil, and a net increase toward the maximum local level supports productivity.
But many farmers are stuck in a debt cycle or are accountable to the supply chain with farm gate contracts that make it hard to take any risks, even if it means adding more risk in the future.
We have to help.
Consumers can educate themselves on agriculture and realise the need to bring food production closer to nature. Not because it is green, lefty, or morally righteous, but because if we stay with an intensive production system with costly inputs, collapse is inevitable.