A practice to mitigate greenhouse gases from a wheat-grown soil by the phosphogypsum waste

Abstract

A large amount of industrial phosphogypsum (Pg) waste pollutes the environment. The reuse of these waste resources in agriculture not only amended the soil and stimulated the crop growth but also decreased the soil greenhouse gas (GHG) emissions. A continuous two-year-field-experiment of the phosphogypsum application in winter wheat was conducted to investigate whether and how phosphogypsum affects soil N2O and CO2 emissions. A two-month lab incubation was also performed to explore the possible mechanism of Pg reducing GHGs. The results indicated that the soil CO2 and N2O was mitigated by the phosphogypsum. Compared to the control (Pg0), the soil N2O emissions in the treatment phosphogypsum decreased by 5.8%-29.9% and the CO2 emission decreased by 2.5%-6.6% in the winter wheat growing season of 2013-2014, while the N2O emission decreased by 20.6%-30.4% and the CO2 emission decreased by 6.2%-9.6% in 2014-2015. The N2O emission declined by 18.9%-28.5% and the CO2 emission declined by 33.5%-50.1% in the lab incubation. The unit weight grain/biomass CO2 and N2O emissions equivalents were reduced by the phosphogypsum. This result suggested that mitigating agricultural GHGs, stimulating crop growth and protecting the environment could be achieved simultaneously by the phosphogypsum.