25% of human-made carbon dioxide and 70% of human-made nitrous oxide being released into the atmosphere comes directly from agriculture. Much of the problem lies in the cropping sequences, tillage, and use of nitrogen fertilizers, all of which raise emission levels.
Growers are getting advice on how to keep soils fertile and productive from Agricultural Systems Research Unit in Sidney, Montana. Upendra Sainju and his team of researchers have been studying no-till systems, crop rotation, nitrogen fertilization, and sheep grazing as methods for reducing the amount of nitrogen polluting the water and air. The ARS demonstrate how these systems are viable alternatives that don’t result in decreased yields.
While fertilizers do have the ability to increase yields, they increase nitrogen runoff and make soils much more acidic. This, in turn, contributes to greenhouse gas emissions.
Fertilizers can increase yields, but they also increase nitrogen runoff and leaching, making soils more acidic and contributing to greenhouse gas emissions. Organic growers have turned to grazing sheep as a means to keep the soil healthy. Careful study has determined that grazing has no negative effects on crop yields and soil quality.
Sainju’s study of different crop management practices showed that organic soil matter was increased with a combination of no-till and traditional farming practices.
Whether or not a field was irrigated, the no-till rotation with a reduced rate of nitrogen fertilization was the most effective way to reduce greenhouse gas emissions and sustaining crop yields.