(The American Society of Agronomy/Biodiesel Magazine) In the U.S., federal mandates to produce more renewable fuels, especially biofuels, have led to a growing debate: Should fuel or food grow on arable land? Recent research shows farmers can successfully, and sustainably, grow both.
Russ Gesch, a plant physiologist with the USDA Soil Conservation Research Lab in Morris, Minnesota, found encouraging results when growing Camelina sativa with soybeans in the Midwest.
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First, researchers planted camelina at the end of September. From there, growing methods differed. 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. Relay-cropping actually used 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,” Gesch said.
Conveniently, the extra water use during dual-cropping takes place in the spring. “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 points out 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,” said Gesch.
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,” said 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. READ MORE Abstract 2014 article Abstract 2015 article (Agronomy Journal)
