There are few clear-cut answers to using biofuels to meet our increasing energy demands. Among questions being debated:
- Are we growing crops for food or fuel?
- Who, if anybody, gets shortchanged?
- What are environmental costs in producing biofuels?
- How cost-competitive are biofuels?
Let’s start with my country, the United States. Federal mandates to produce more renewable fuels, especially biofuels, have led to a growing debate: Should fuel or food grow on arable land? Remember a few years back when massive corn scarcity was threatened due to the production of ethanol? Recent research published by the American Society for Agronomy suggests Midwest farmers can successfully, and sustainably grow both — one in winter, the other in summer. The crop combo undergoing research is Camelina sativa with soybean.
Russ Gesch, a plant physiologist with the USDA Soil Conservation Research Lab in Morris, Minnesota, reports encouraging results when growing the two crops in the Midwest.
“Finding any annual crop that will survive the [Midwest] winters is pretty difficult,” says Gesch, “but winter camelina does that and it has a short enough growing season to allow farmers to grow a second crop after it during the summer.”
Camelina is a member of the mustard family and an emerging biofuel crop. It is well suited as a cover crop in the Midwest.
For growing two different crops on the same land parcel, water demand must also be considered. In the upper Midwest, soils need to retain enough rainwater for multiple crops in one growing season. Gesch and his colleagues measured water use in two systems of dual-cropping using camelina and soybean. The research team compared it with a more typical soybean field at the Swan Lake Research Farm near Morris, Minnesota. First, researchers planted camelina at the end of September. Different growing methods were used in conducting research — relay-cropping and dual-cropping. In double-cropping, soybean enters the field after the camelina harvest in June or July. Relay-cropping, however, overlaps the crops’ time. Soybeans grow between rows of camelina in April or May before the camelina plants mature and flower.
The benefits were numerous. Gesch said relay-cropping required less water than double-cropping the two plants. Camelina plants have shallow roots and a short growing season, which means they don’t use much water. “Other cover crops, like rye, use a lot more water than does camelina.”
Conveniently, the extra water required during dual-cropping takes place in the spring, a good moisture season in the Midwest. “We tend to have an excess of moisture in the soil in the spring from the melting snow pack,” said Gesch. Growing camelina as a winter cover crop can help farmers take advantage of spring’s extra moisture. Gesch added the need for more water use does mean camelina dual-cropping may not be the best option in all areas. “As you get further west and precipitation drops off and soils get lighter with lower water-holding capacity, crop yields may start to go down,” he said.
Growing camelina as a winter cover crop can also have other benefits, according to Gesch.
“We had greater soybean yields with the relay-cropping system than when double cropping,” says Gesch, referencing a previous study. The earlier planting date during relay cropping allows for a longer growing season and contributes to the higher yield, according to Gesch. In addition, camelina plants flower early in the spring, providing a vital food source for pollinators like bees, when little else is available to them. As a cover crop, camelina may also help prevent erosion and build soil carbon content. Gesch and his colleagues are working to measure these ecological benefits of dual-cropping.
“We wanted to find alternative crops that could be integrated into the Midwestern corn/soybean cropping system in a sustainable way that also makes economic sense for farmers,” says Gesch. In camelina, they may have found just such a plant.
Gesch’s study was recently published in Agronomy Journal. This research will hopefully provide viable options for American farmers wanting to grow their businesses into viable entities that can operate sustainably, providing both food and biofuels which might be used in facing the overwhelming challenges associated with climate change. If successful, the next challenges will be economic ones. Can this biofuel be a clean burning and cost-competitive ingredient in meeting the staggering growth of our population’s overall transportation demand. We will hopefully find out in good time.
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