How can a Biofuel Crop Help to Combat Climate Change?

A new study from Michigan State University explains how switchgrass, a biofuel crop, can help mitigate the effects of climate change when grown on marginal land, or low-value agricultural land. It may also provide economic returns in these otherwise unproductive spaces for farmers. The findings were published in the journal Environmental Research Letters.

Findings of Study:

Bruno Basso, an MSU Foundation Professor in the departments of Earth and Environmental Sciences, Plant, Soil and Microbial Sciences, and the W.K. Kellogg Biological Station, led the team. Rafael Martinez-Feria, a postdoctoral researcher in Basso's laboratory, and Seungdo Kim, an associate research professor in the MSU College of Engineering, were also involved.

Renewable energy is a hotly debated topic all over the world. Climate scientists warn of disastrous consequences if fossil fuels continue to be the primary energy source in the future. Furthermore, countries such as the United States are grappling with the ethical and financial ramifications of relying on foreign oil.

Lignocellulosic biofuels, which are made from plant biomass, are one of the few current renewable energy sources with the potential to be used as a vehicle fuel alternative. However, simply planting more biofuel crops like switchgrass will not solve the problem of fossil fuels.

"Growing enough biofuel crops to use on a large scale in the transportation sector would necessitate massive land-use changes," Basso said. "This is a multi-layered problem. There are concerns about food security if land previously used for food crops is converted to biofuel crops. There are also concerns about greenhouse gas emissions if land that is not currently used for agriculture, such as wildlife habitat, is taken over by crop production systems."

The problem is exacerbated when farmers consider what to do with marginal, underutilized land. With rising input costs, there is frequently little to no benefit to planting in these areas. If growers do decide to plant, environmental concerns abound, as these fields are frequently nitrogen-deficient and may necessitate heavy fertilizer use.

"In order to persuade farmers to change their behaviour, the change must first and foremost make economic sense to them," Basso explained. "Our goal was to see if marginal lands could be profitable while also being environmentally conscious, which would be a win for everyone involved."

Basso and his colleagues used a multi-model ensemble of crop simulation systems that took soil, weather, and management data into account for this project. Three previous studies' models were included, as well as Basso's System Approach to Land Use Sustainability (SALUS) programme, which simulates daily crop production over many years using various management strategies.

The multi-model ensemble is intended to help better understand and quantify the uncertainties caused by model input and model parameters that are unique to each model. According to Basso, this is the first study to use an artificial intelligence-linked model ensemble for switchgrass used in bioenergy production.

Basso's team discovered that low levels of nitrogen fertilizer provided long-term yield increases that outweighed greenhouse gas emissions, a finding that contradicts previous research. Researchers believe the benefit will be much greater on lands that are limited by nitrogen deficiency, as is the case in several areas of Michigan. This strategy, according to Basso, is less effective in areas with high soil organic carbon, as well as in areas with low precipitation and short growing seasons.

"This demonstrates that some nitrogen-deficient marginal lands have potential value for biofuel crop production, which is of interest to farmers looking to increase profitability and of environmental importance by reducing the operation's carbon footprint," Basso said. "It's critical that we don't create another problem by attempting to solve one, so the levels of added nitrogen fertilizer are critical to maintaining the overall net-positive climate result."