“Early yield estimates were based on data from small research plots, but they weren’t realistic. Our main goal with this project was to determine whether these species could be viable crops when grown on the farm scale,” says D.Ok. Lee, affiliate professor within the Division of Crop Sciences on the College of Illinois and chief of the prairie combination portion of the study.
The mission, backed by the U.S. Division of Power and the Solar Grant Initiative, started in 2008 and consists of researchers from 26 establishments. Collectively, they evaluated the bioenergy potential of switchgrass, Miscanthus, sorghum, energycane, and prairie mixtures in long-term trials spanning a large geographical space.
Due to shortages in plant supplies, Miscanthus and energycane have been grown on smaller plots than the opposite crops, however researchers say the brand new outcomes are nonetheless precious for producers.
“Although making real-world decisions and recommendations based on performance data from small plots is less desirable than from field-scale plots, we feel comfortable with the Miscanthus results since they were based on 33 data sets collected from five sites over seven years,” says Tom Voigt, professor within the crop sciences division at U of I and chief of the Miscanthus portion of the study.
Crops have been grown for 5 to seven years in a number of areas and with various ranges of nitrogen fertilizer. Though many of the crops are recognized to tolerate poor soil high quality, the researchers discovered that all of them benefitted from not less than some nitrogen. For instance, Miscanthus did finest with an software of 53.5 kilos per acre.
“When we didn’t fertilize with any nitrogen, yields dropped over time. But if we used too much, 107 pounds per acre, we were increasing nitrous oxide emissions and nitrate leaching,” says Voigt. “There is some need for fertilization, but it should be tailored to specific locations.”
Prairie mixtures, which have been grown on land enrolled within the Conservation Reserve Program (CRP), additionally benefitted from added nitrogen. Yield saved growing with the addition of up to 100 kilos per acre, however Lee says producers would have to weigh the yield profit towards the price of the fertilizer.
“Even though it increased yield, it is economically not profitable to use more than 50 pounds of nitrogen per acre.”
And though many of the crops are considerably drought-tolerant, precipitation made a distinction.
“Miscanthus production was directly related to precipitation,” Voigt says. “In areas where precipitation was down, yields generally dropped. However, it did depend on timing. If there was a good amount of water in the winter, plants could get going pretty well in the spring. But if we had little rainfall after that, that hurt yields.”
Lee says prairie mixtures, that are usually made up of hardy grasses, suffered from the extreme droughts in 2012 and 2013 in some areas. “In one year in our Oklahoma location, they didn’t even try to harvest. Yield was too low.”
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Nobody feedstock “won” throughout the board. “It depends so much on location, nitrogen application rate, and year variability,” Voigt says. As a substitute of highlighting particular yields obtained in good years or areas, a bunch of statisticians throughout the analysis crew used field-based yield and environmental information to create maps of yield potential for the 5 crops throughout the U.S. Darkish inexperienced swaths on the maps characterize areas of highest yield potential, between 8 and 10 tons per acre per yr.
In accordance to the brand new outcomes, the best yield potentials for lowland switchgrass varieties are within the decrease Mississippi valley and the Gulf coast states, whereas Miscanthus and prairie combination yields are doubtless to be biggest within the higher Midwest.
Lee says the prairie mixtures, that are usually grown on CRP land to preserve soil, didn’t stay up to their potential within the study. “We know that there are higher-yielding switchgrass varieties today than were included in the CRP mixtures in the study. If we really want to use CRP for biomass production, we need to plant highly productive species. That will bump yield up a lot higher.
“One of the biggest concerns now is that CRP enrollment is shrinking. When we started, we had 36 million acres nationwide. Now we’re down to 26 million.
Farmers feel they could make more money by using that land for row crops. We need to find some solution if we want to save the soil. Biomass could provide revenue for farmers, if they were allowed to harvest it,” Lee says.
Energycane might attain very excessive yields, however in a comparatively restricted portion of the nation. Nonetheless, the crop that shows the very best potential yields within the biggest variety of areas is sorghum. The annual crop is extremely adaptable to numerous circumstances and is likely to be simpler for farmers to work with.
“It fits well in the traditional annual row-crop system; better than perennial crops. It may not be environmentally as desirable as perennial crops, but people could borrow money in winter to buy seed and supplies, then plant, and sell in the fall to pay back their loans. It’s the annual cycle that corn and beans are in,” Voigt says.
Lee provides, “In terms of management, sorghum is almost the same as corn. It germinates and grows so quickly, weed control is not a big issue. If you plant by early June, it will be 15-20 feet tall by September. It also has good drought tolerance.”
Downsides to the biomass champ? It’s moist at harvest and can’t be saved. It additionally requires nitrogen and can lodge, or collapse, prior to harvest in moist or windy circumstances. “Still, it’s a really spectacular plant,” Voigt says.
The researchers made all of the uncooked information from the study out there on-line for anybody to entry. Lee says it may be helpful for everybody: scientists, policymakers, and producers. “It should be helpful for number of different stakeholders,” he says.