In July, an EU project began that aims to transform poor-quality land into the basis of new biobased supply chains.
The RUNFASTER4EU project wants to demonstrate that crops grown on marginal land can become sustainable energy and materials products at an industrial scale.
Marginal land is getting more attention from biobased entrepreneurs and policymakers as a sustainable raw material source.
But what is marginal land? And how do crops from them make the biobased industries more sustainable?
How marginal land benefits biobased industry
Marginal land refers to agricultural sites that are not economically viable to cultivate for human food or animal feed. This could be agricultural land that has been abandoned, land degraded through ground pollution, or has soils that struggle to retain moisture and nutrients.
One estimate has placed marginal land at 38-53.5 million hectares in the EU and the United Kingdom. Climate change is set to increase this amount in certain regions.
Marginal lands may not support food crops, but they can support industrial crops for energy and renewable materials.
Sourcing feedstock from marginal land tackles a major objection to certain biobased energy and material products: that expanding industrial cropland can reduce land for growing human food or for biodiversity conservation.
Environmental arguments intersect with economic ones here. Increasing the pool of low-cost biomass feedstock is key to lowering the prices of biobased goods. Using crops from marginal land can achieve this without adding unnecessary burdens on the environment.
This is because almost by definition, crops that can thrive in marginal land generally demand less of the energy-intensive soil conditioners, fertilisers, and water resources that other crops would need. The minimal resource demands of these plants means that they can become the foundations of maximally low-carbon industrial supply chains.
In some contexts, planting the right species on the right kinds of marginal land can boost biodiversity.
Switchgrass: biofuel substitute
US renewable supply chains are developing at a steady clip, driving up demand for quality biomass feedstock. The country has an estimated 11% of the contiguous landmass considered marginal land. In these areas, only a few commercially profitable species could thrive. One of them is Switchgrass, a high-yielding source of biofuel.
Switchgrass is one of the most well-known feedstock crops. The deep-rooted grass is native to the Central North American Plains and so well-suited to poorer soils.
Corn is the main biofuel feedstock in the US but on certain marginal lands, switchgrass can make more economic sense. The exact profitability of cultivating Switchgrass depends on which varieties you plant where, as well as the price for biofuels at a given time. Field research shows input costs vary for different cultivars in different soils across the US Midwest.
Apart from providing lower-carbon fuels, these grasses can also improve soil carbon storage where they grow. Researchers found that when switchgrass was planted in highly eroded, sandy loam soils in Oklahoma’s Dust Bowl-remnant fields, soil carbon levels quickly rose there.
Similar results were found by a team at the University of Colognia, which planted a large switchgrass field site at the university experimental farm back in 2007. After 13 years, there was a significant increase in soil carbon.
Switchgrass has different carbon impacts depending on soil type and location, so careful site-by-site monitoring is essential. Where the crop can raise the net carbon retention of soil, it can provide a low-cost way to reduce planet-warming gases in the atmosphere.
There is also a lot of research that indicates that when planted on previously degraded or unused sites, switchgrass has more positive biodiversity impacts than corn biofuel crops, particularly on pollinator insects and birds.
Miscanthus: a marginal all-rounder
Miscanthus (or elephant grass) is another plant that grows happily on marginal land.
So far, the plant has found more diverse applications than Switchgrass, including in packaging, construction, and even equestrian sports.
In the equestrian industry, ArenaMend has developed Miscanthus fibres that can be used to fill out the sandy surfaces inside riding arenas. These fibers are meant to replace toxic synthetic materials commonly found in arena surfaces, such as tiny plastic granules or shredded carpet.
In Dorset, England, the company Agrikinetics is investigating how to turn local Miscanthus plants into pulp for packaging. Packaging made from the plant could have a far lower environmental impact than using virgin wood pulp, which is relatively slower-growing and can come from unsustainable forestry sites.
The company’s Miscanthus-promoting activities do not end there. The UK firm is solely dedicated to Miscanthus product development. It says the crop is especially suited to rural revitalisation, as it lends itself to decentralised, small-scale production by producers located in the countryside.
Indeed, Miscanthus grows well in almost any setting, including urban and semi-urban sites we would not normally associate with agriculture.
One unlikely haven for Miscanthus is on land near aviation runways. In the Netherlands, this humble grass has been planted around the country’s Schiphol airport, where it serves a dual function: it offers a natural way to ward off birds while providing local bio-businesses with a sustainable feedstock source.
Geese are naturally afraid of the tall and dense Miscanthus plants. When planted around airports, the birds are less likely to disembark near the runway, reducing the likelihood of deadly collisions with aircraft.
Some of the Miscanthus grown around the airport has gone to local biobased business BioBound, which has made concrete paving stones with the grass. These paving stones were recently installed at the airport.
The outdoor benches in front of the terminal are also made from Miscanthus-based bio-concrete. The material is circular because at the end of their lives they can be broken up and used again as insulation material.
The Midas touch
Switchgrass and Miscanthus are only the most well-known industrial crop species suited to marginal land. Soon, we could have our pick of new plant varieties that can withstand unfavourable soils.
The EU’s MIDAS project is developing new, non-edible plant varieties that can grow in marginal soils mapped around the region.
Their objective is to selectively breed crops that can provide reliable industrial feedstock, including under a warming climate, while also restoring biodiversity in certain parts of Europe.
The crop species they are working with include safflower, crambe, cardoon, castor bean, and poplar – all species naturally predisposed to arid conditions.
Some of the industrial products that can be made from these plants can nourish soil elsewhere: technologies: biochar, bioherbicides, biostimulants, and mulching film made from marginal crops could improve land efficiency in dry Mediterranean areas.
Certain crop species that grow in marginal areas can provide a host of benefits for wildlife, particularly for the insects vital for pollinating our food crops. MIDAS is aiming for plant varieties that can expand feedstock supply for biobased products and give back to the soil and ecosystems where they grow.
Marginal isn’t always unproductive
Converting every single piece of unused land to feedstock growing is not the point either.
Some uncultivated land may appear unproductive. On closer inspection, they can actually be vital for sustaining livelihoods that turn around foraging, subsistence farming, and pasturage for indigenous peoples, pastoralists and the rural poor around the world.
This signals a wider point about building sustainable economies. As well as industrial decarbonisation, sustainability must include social aspects, like preserving traditional cultural and economic practices that already respect the physical limits of our planet.
Traditional uses of marginal land can provide countries with irreplaceable public and ecological benefits just as they stand today. The search for industrial sustainability therefore cannot ignore these existing uses: In some cases, marginal lands may better serve overall environmental goals if left to communities that engage in low-intensity farming and foraging.
Converting unused marginal land into sources of industrial feedstock must be done in a strategic manner that can expand biomass supply without negative social impacts. To achieve this, policymakers must set out clear criteria for deciding when a piece of marginal land is best used for industrial feedstock rather than any other uses, including for subsistence.
Certification schemes that evaluate the ethical impacts of supply chains must have a way for assessing whether the biomass supply displaced traditional resource use.
Even given these constraints, the world still has a lot of marginal lands to offer that are ideal for industrial crop production. Crops grown on these demand few resources and can keep land competition for food and wildlife to a minimum.
From the innovations already on the market, it is clear that almost every industry could benefit from feedstock grown in marginal sites.
Feedstock crops that can grow on marginal land do not just provide a sustainable resource for today but a source of economic security for tomorrow. Plants that can offer food, fuel, and materials even under unfavourable conditions will become increasingly important as climate change makes growing conditions more volatile. The biobased industry’s increasing interest in marginal crops is therefore crowding R&D and investment into a vital area.