UNL studying whether char from sugarbeet plants will improve soil
UNL studying whether char from sugarbeet plants will improve soil
By: Midwest Producer and University of Nebraska-Lincoln
November 23, 2016 8:00 am, published with permission
SCOTTSBLUFF, Neb. — Scientists from the University of Nebraska-Lincoln have begun a multi-year study into whether high-carbon char, a fine, powdery coal dust left over from the processing of sugarbeets, will improve the soil if applied to farmers’ fields.
Western Sugar Cooperative produces 35,000 tons of char each year as a byproduct at its sugar manufacturing plant in Scottsbluff. Western Sugar has plants and other storage and delivery facilities for sugarbeets in Nebraska, Wyoming, Colorado and Montana.
Researchers from UNL’s Panhandle Research and Extension Center and also the Lincoln campus of UNL’s Institute of Agriculture and Natural Resources are beginning a three-year study in which they will apply high-carbon char to several research plots near Scottsbluff. The char will be applied once at several different rates (ranging from 0 up to 25 tons per acre), incorporated into the soil, and crops will be planted in a four-year rotation that includes sugarbeets, corn and dry edible beans.
The research team will measure crop yields as well as changes in the soil physical properties (infiltration, crusting, water holding capacity, density, color), and chemical properties (carbon, pH, salinity and soil nutrient levels).
The potential soil-quality benefits include an increase in organic matter and soil carbon. Higher concentrations of carbon in the soil reduce crusting, rapid soil-surface drying and compaction, and improve soil structure, water infiltration, water-holding capacity, and microbial activity. Decades of crop production have depleted organic matter and soil carbon from many fields in western Nebraska, according to Gary Hergert, retired soils specialist at the Panhandle Center, who is advising the research.
The project has the potential turn into a long-term effort involving generations of scientists, much like the adjacent Knorr-Holden corn plots, established 114 years ago in 1912.
It is one of a very few, and possibly the only, large field-plot-scale project in the United States to study the effects of biochar, according to Hergert.
For Hergert, the biochar project came about as the result of a convergence of several factors. Several years ago he did research into treating soil with another Western Sugar byproduct, precipitated calcium carbonate (PCC for short).
PCC is lime left over from the process of extracting pure sugar crystals from the raw juice removed from sugarbeets. In the earlier project, Hergert and other scientists at the Panhandle Center applied PCC to 30 fields in Nebraska, Colorado and Wyoming. The PCC added some nutrients but did not have a significant positive effect on soils. It also did not have any negative effects on the soil or crops.
Plots are still being monitored to see if the PCC helps reduce Aphanomyces, a sugarbeet disease. Research in other areas has shown a reduction in this disease.
But another byproduct produced at Western Sugar factories is high-carbon char. According to Hergert, the plants at Scottsbluff and Fort Morgan, Colo., generate 35,000 tons per year of the sooty powder from coal that is burned incompletely to heat the lime for the sugar-refining process.
Char is carbon-based, and numerous research papers show that carbon can be used to enhance soils, Hergert said. Additionally, charcoal has been used to improve soils in the Amazon River basin in South America for 2,500 years or more. The natives of the region would create charcoal and incorporate it into small plots of land.
Coincidentally, Hergert had been hearing about biochar and its potential for several years at agronomic society meetings.
Research into biofuel alternatives to ethanol had been on the increase since growth in ethanol was capped in the new Renewable Fuel Standard by the Energy Independence and Security Act of 2007 (EISA). The new Renewable Fuel Standard capped production of corn ethanol, but called for increases in other types of biofuels that had a greater reduction in greenhouse gases. Hergert said this led to the expectation that other biofuel sources, such as cellulosic materials like irrigated grasses, would grow in importance.
One potential ethanol addition is second-generation biofuels created by pyrolysis, the heating of cellulosic substances to create an oil-like substance. Biochar is a leftover remain of pyrolysis. Research conducted elsewhere on its agronomic effects has been on small-scale, greenhouse-size plots, due to lack of federal funding and congressional follow-through that would support second-generation biofuels, according to Hergert.
To date there are no commercial-scale pyrolysis plants in the United Sates. Little, if any, of the research has been conducted on field plots.
But there are large piles of char, which is very similar to the biochar, near the region’s beet sugar refineries. And there are field plots at the Panhandle Research and Extension Center. And now, thanks to funding from the Western Sugar Cooperative Research Committee, there is a multi-year project to see if char applications will benefit the soil.