Energy or food, what would you choose?

One of the major global challenges we are currently faced with is providing enough food for our ever-growing global population. As most people are aware now, the global population is going to increase from 7.3 billion to roughly 9.7 billion by 2050. We are already facing issues with food shortages and famine, particularly across sub-Saharan Africa, so increasing agricultural productions to feed a further 2 billion people is an enormous challenge. To further complicate the issue, as countries begin moving away from dirty fossil fuels to clean energy, biofuel production has increased. Biofuel competes directly with food production as biofuels are typically made from crops such as maize, sugar cane and palm oil. A major concern is that the cost of food will most likely increase as a result (yes, you may have to pay more for that bag of Doritos in the future). Biofuel crops are farmed so intensively that they also cause serious harm to our environment. Let’s take palm oil as an example. It is widely linked to the destruction of the rainforest, particularly throughout Southeast Asia, which is home to endangered species such as the orang-utan and Sumatran elephant.

World population growth, by Lauren Manning

We are constantly faced with the enormity of these doom and gloom statistics and it is easy to become overwhelmed by the scale of these issues. So, instead of continuing to focus on the bad, let us take a look at some of the promising research being done to find the solutions we need. Over recent years, there has been growing interest in the use of marginal land to grow crops for biofuel production. Marginal land tends to have poorer soils that are not suited for growing high value crops. Researchers have proposed using this land to grow a mixture of native and non-native perennial grasses and woody plants, for the sole purpose of energy production. The benefits would include less CO2 emissions, higher yield rates, increased water quality and habitat availability for beneficial wildlife.

What’s better is that perennial crops can also be used to make renewable diesel, which can be used to directly replace the diesel we are currently pumping into our cars. However, as always, there are some limitations. Farmers will still need to make enough money off the perennial crops to make them worth growing, particularly as weed control is quite intensive in the first two years of growth. Also, an alternative use of this marginal land is planting native shelterbelts, which increases the biodiversity and ecosystem values on farm (such as increased pollination). Farmers will need to determine whether they value growing the perennial crops more than the benefits brought from having higher biodiversity on farm.

Rakaia River, Canterbury Plains. By Mark Adeane

Shelterbelts are important for improving the sustainability of farming systems, but their value has been undermined in recent times. As a result, in many areas shelterbelts are being completely removed, usually as a result of installing centre-pivot irrigation systems. The loss of shelterbelts leads to increased erosion as there is no protection from the wind and lower water quality, as there is no buffer to filter water before it enters the waterways. Livestock welfare also suffers as shelter from wind, sun, rain or snow is removed. This is particularly relevant to the Canterbury region, which has had a major shift to dairy farming over the past two decades. As a result of this shift, the Canterbury plains is now a large, flat, treeless landscape with very low biodiversity, which has increased the public perception that dairy farming is unsustainable.

Chris Littlejohn and his colleagues Tim Curran, Rainer Hoffman and Steve Wratten published a study at Lincoln University, New Zealand that investigated the ability to integrate perennial biofuel crops into farming systems by using them as shelterbelts. They identified that Mxg, a grass species that originates from Asia, would be suitable because it has a long lifespan of 20 years, can be harvested every year, has an end height of 4 metres and grows best under irrigation. Because Mxg is a grass, centre pivot irrigators can easily push through them, which removes the height constraint of traditional, tree-dominated shelterbelts. The research found that if a shelterbelt was planted around a 100ha paddock, then this would produce around 63 000 litres of renewable diesel a year (valued at $8053 USD per hectare per year).

Skink, by Jon Sullivan

There are some obvious moral dilemmas for many ecologists as Mxg is not a native species and would not provide additional habitat for native wildlife. A further worrying feature is that Mxg shelterbelts also provided refuge to mice, who are known to prey on bumblebees and other invertebrates. Mxg may also attract possums and stoats to the area, which would be bad news for the already struggling native bird populations. However, shelterbelts have not traditionally been composed of native species and it was found that Mxg provided refuge for nesting bumblebees as well as habitat for skinks, so would still provide increased ecosystem services if mice numbers are managed. There is little suitable habitat for skink populations on the Canterbury plains, so this could help boost their population sizes. The Mxg shelterbelts would reduce erosion by providing protection from wind and would reduce contamination of waterways through increased filtration.

These promising results have presented the Canterbury Plains has a unique opportunity to revolutionise the use of shelterbelts in an environmentally and economically beneficial way. If successful, this could help promote using marginal land on farming systems around the world to produce renewable diesel, while reducing competition with crops for food production. This is one way we could feed the extra 2 billion people expected by 2050.

Here’s the link to the paper if you want to find out further information:

Littlejohn, C., Curran, T. J., Rainer, W., & Wratten, S. (2015).

Farmland, food, and bioenergy crops need not compete for land. Solutions.

The author Claire McCorkindale is a postgraduate student in the Master of Natural Resources Management and Ecological Engineering taught jointly at Lincoln University and BOKU, Vienna. She wrote this article as part of her assessment for ECOL 608 Research Methods in Ecology.

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