Today much of American agriculture consists of industrial-scale, chemical-intensive, single-row crop farming—with corn and soybeans being dominant, particularly in the Midwest.
Unfortunately, the natural environment has suffered as a result of this. Growing corn, soybeans, and other row crops contributes significantly to overall emissions of the greenhouse gases (GHGs) that accelerate climate change. The Minnesota Pollution Control Agency says agriculture contributes 25 percent to the GHG emissions in the state.
More and more Minnesota farmers and University of Minnesota researchers are deeply engaged in identifying how agricultural practices might change in the future to reduce emissions and better protect soil and water, thereby benefiting the climate. Since much of ag research takes place in the field, those two categories—farmers and researchers—often overlap, and there are examples all around the state of Minnesota, led by the U of M.
Safeguarding the soil
One approach that could make big strides toward a greener Minnesota relatively soon is switching to ag management practices that better protect the soil, which is a huge repository for the carbon that is both necessary for life and a major cause of warming when released into the atmosphere. (Carbon in soils can be released into the air through a variety of agricultural tasks, including overuse of fertilizer, tilling, monocropping, and other practices.)
“Soil is the world’s largest reservoir of carbon, much larger than the ‘pool’ of carbon in the atmosphere,” says Anna Cates, soil health specialist with the Minnesota Office for Soil Health—a collaboration of the Board of Water and Soil Resources and the U of M Water Resources Center. “[Industrial] agricultural practices have caused us to lose a lot of nutrients, especially carbon. We’re in a deficit; a lot of the carbon that was in the soil is now in the atmosphere.”
Soil conservation strategies include planting cover crops, no-till and reduced tillage farming, switching from corn and soybean rotations to perennial grains such as crested wheat grass, or restoring fields to native grasslands. To reduce carbon emissions from the soil, “reducing tillage is one of the lowest-hanging fruit farmers can undertake,” Cates says. “It’s not always possible with certain crops and takes a little bit of a learning curve on how to manage impaction, weeds, etc., but in working with Extension educators and ag retailers, that is a place where some gains can be probably made very quickly.”
Switching to alternatives
Another primary strategy to shift agriculture’s impact on the earth is switching from petroleum-based energy to alternatives like wind energy and biogas. The goal is to make farms “carbon neutral” operations.
Dennis Haubenschild contends agriculture has the potential to supply 40 to 50 percent of the nation’s renewable energy “if we used all of the tools available.” Among the tools Haubenschild and his sons use on their farm near Princeton, Minn., are 1,600 cows, each of which produces about 80 pounds of manure per day. Burning the manure inside an anaerobic digester produces energy in the form of biomethane. The gas can be used to power a turbine to generate electricity and heat, or it can be fed into a natural gas pipeline to be sold to a local utility.
The digester the Haubenschilds began using in 2000 produces 100 to 125 kW per hour—enough electricity to power their dairy operation, plus 40 homes.
Where the sun shines
Along with conventional crops, Ralph Kaehler harvests energy directly from the sun on his family’s fourth-generation farm near St. Charles, Minn. The family’s “other” business, Novel Energy Solutions LLC, has installed more than 200 solar systems since it opened in 2012 and developed more than 100 megawatts of community solar garden (CSG) projects, including the first four CSGs in Xcel Energy’s Minnesota territory.
A typical on-farm array is a 40-kilowatt system that produces about $415 per month at a 10 cents per kilowatt-hour electric price, says Kaehler. A 40 kW array costs about $90,000 for a cash purchase, with a payback time of eight to 12 years.
“Solar panels are just the beginning,” says Kaehler, who has worked with U of M researchers as a co-researcher and consultant. “... We will be using fossil fuels for some time, but we can’t keep using them at the rate we have been. If we are going to leave a world with opportunity for our kids and grandkids, we are going to have to change.”
Source : umn.edu