Emerging Land Use Practices Rapidly Increase Soil Organic Matter

Authors: Megan B. Machmuller, Marc Gerald Kramer, Kevin Taylor Cyle, Nick Hill, Dennis Hancock, Aaron Thompson

ABSTRACT

The loss of organic matter from agricultural lands constrains our ability to sustainably feed a growing population and mitigate the impacts of climate change. Addressing these challenges requires land use activities that accumulate soil carbon (C) while contributing to food production. In a region of extensive soil degradation in the southeastern United States, we evaluated soil C accumulation for 3 years across a 7-year chronosequence of three farms converted to management-intensive grazing. Here we show that these farms accumulated C at 8.0 Mg ha(-1) yr(-1), increasing cation exchange and water holding capacity by 95% and 34%, respectively. Thus, within a decade of management-intensive grazing practices soil C levels returned to those of native forest soils, and likely decreased fertilizer and irrigation demands. Emerging land uses, such as management-intensive grazing, may offer a rare win-win strategy combining profitable food production with rapid improvement of soil quality and short-term climate mitigation through soil C-accumulation.

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