The biggest impact a typical row crop farm has on climate change, by far, is connected to the use of nitrogen. The production of nitrogen is energy intensive and results in significant carbon dioxide emissions. In addition, excess nitrogen in the soil results in the atmospheric release of nitrous oxide — a substance nearly 300-fold more damaging to the climate than carbon dioxide. By reducing the level of nitrogen being used on the farm, a grower can cut the farm’s greenhouse gas emissions.
This can be a challenge. Farmers know nitrogen drives yield with most crops, so suggesting they use less can lead to short conversations. Very short. So we talk with them about nitrogen efficiency. Many of them are not willing at the outset to cut nitrogen application per acre, but when their yield goes up, and nitrogen is stabilized through our recommended practices, their use of nitrogen per unit of food grown declines. That’s a big — and important — change. The farmer saves money through nitrogen efficiency, and the climate benefits through reduced emissions per unit of food grown.
Midwestern BioAg constructs fertilizer blends and soil amendments with an eye toward engaging soil microbes, cycling nutrients and feeding plants. By enlisting the full array of micronutrients, linking them to carbon sources and timing releases throughout the growing season, we feed both the microbes and the plants. This pulls applied nutrients — including nitrogen — into the soil’s food chain. It keeps the nutrients in the soil, in a more plant-available form, instead of allowing them to leach into the water or escape into the atmosphere.
Applying balanced, well-timed fertilizers and soil amendments can lead to important efficiency gains. Even bigger improvements come when growers deploy our whole biological farming system, which includes high-quality fertilizers and soil amendments, cover crops, prescriptive tillage and diverse crop rotations. Cover crops can scavenge and build nitrogen levels in a field — allowing for significant reductions in applied synthetic nitrogen in the subsequent growing season. Shallow tillage allows cover crops and plant residue to be incorporated in the soil, but avoids the deep cuts that can be harmful to soil life. Specific crop rotations (corn following oats plus cover crops, for example) can lead to greater nitrogen efficiency over multiple growing seasons.
When producers use our system for multiple years, ample evidence shows their nitrogen use per unit of food grown is reduced. Corn grown on our system can require only 0.5 to 0.7 pounds of synthetic nitrogen per bushel; the average recommendation in the Midwest is roughly 1.2 pounds. We do this by optimizing nitrogen fixation through specific rotations, fixing and capturing unused nitrogen through cover crops, and making that nitrogen available via highly biological soils.
In 2015, we worked with a major food company to see if we could grow oats with greater nitrogen efficiency. We identified 47 fields, with a total of 2,070 acres, all of them on farms that had been using our products for multiple years. The food company’s supply chain typically sourced oats produced with 0.8 to 1.0 pounds of nitrogen per bushel. Our customers produced oats with 0.44 pounds of nitrogen per bushel — a 45 percent savings in nitrogen use.
Our approach consistently builds soil organic matter (SOM). This comes from increased biological activity in the form of microbes and other soil life. And that biological activity speeds crop residue decomposition, again boosting soil organic matter.
SOM is a key indicator of farmland productivity — and a key indicator in establishing the investment value of a farm. It is a reflection of healthy soil life. It also has water use and crop resiliency benefits: With every 1 percent increase in SOM, an acre can hold an additional 20,000 gallons of water, reducing demand for fresh water.
The climate benefits are also significant. Increasing SOM by 1 percent on one acre embeds 15 to 20 tons of carbon dioxide equivalents in the soil. As carbon markets mature, we expect to work with our farmers to help them turn these savings into dollars on carbon markets.
Because our process often starts with soil samples, we have many sets of before-and-after samplings. Though sampling methods have changed over time, these farm-level data sets consistently show increases in SOM. We’ve seen isolated examples of a 1 percent increase in SOM in as little as three years, but a conservative estimate suggests the more typical pace for a 1 percent increase may be ten years. Every 1 percent increase in organic matter adds approximately 20,000 pounds of carbon per acre.