|Lang, David - Mississippi State University|
|Mcgrew, N. - North America Coal Cooperation|
Submitted to: Journal of the American Society and Mining and Reclamation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2019
Publication Date: N/A
Interpretive Summary: Broiler chicken and swine farms in Mississippi generate large amounts of animal waste byproducts, specifically poultry litter and swine mortality compost, respectively. A team of scientists conducted a four-year study to determine if these organic byproducts improve the fertility and productivity of reclaimed soil at a lignite coal mine. The land reclamation study was done in cooperation with Red Hills Mine in northeast Mississippi to compare soil and plant responses to organic byproducts with the mine’s standard fertilization of commercial NPK fertilizer. The three fertility treatments were applied to plots of common bermudagrass each year (2011-2014) with and without the co-application of flue gas desulfurization (FGD) gypsum, a byproduct of the coal industry, giving six treatments. Because FGD gypsum is considered a “soil conditioner” that can enhance aggregate formation and water infiltration, soils amended with FGD gypsum may tolerate higher levels of organic soil amendments and would therefore be more productive in the long-term. As compared to NPK fertilization, applying 10 tons/acre of organic amendments for four years significantly increased soil pH, organic matter, cation exchange capacity, and P and K levels in surface soil (0- to 15-cm depth). Regardless of fertility amendment, the use of FGD gypsum decreased soil organic matter by approximately 27% in samples taken from the surface (0- to 15-cm) and subsurface (15- to 30-cm) depths. Averaged across fertility amendments, the use of FGD gypsum decreased soil test K, but increased cation exchange capacity and soluble salt concentration in surface soil. Annual dry matter yield of bermudagrass was consistently greater with poultry litter than either swine compost or NPK fertilizer. Additionally, the height/diameter ratio of loblolly pine was least with poultry litter, suggesting these trees have improved stability. Repeatedly applying poultry litter for four years to reclaimed coal mine soil improved soil quality and plant growth parameters in a respread area.
Technical Abstract: Knowledge of soil and plant responses to animal or industrial byproducts is needed for effective use of these amendments on reclaimed mine soils. A 4-yr study (2011-2014) at a surface lignite mine in northeast Mississippi determined soil chemical, common bermudagrass, and loblolly pine responses to animal waste and flue gas desulfurization (FGD) gypsum. The study was a 3 × 2 factorial randomized complete block design with three replicates consisting of 22.4 Mg ha-1 poultry litter, 22.4 Mg ha-1 swine mortality compost, and 896 kg ha-1 NPK fertilizer (13-13-13; the standard practice), with and without co-application of 11.2 Mg ha-1 FGD gypsum. Soil amendment treatments were incorporated to 15-cm depth in May 2011 and applied without incorporation in 2013-2014. Soil samples were collected periodically at 0- to 15-cm and 15- to 30-cm depths. Compared with inorganic fertilizer, applying organic amendments increased (P < 0.05) soil pH, organic matter, cation exchange capacity, and P and K levels at 0- to 15-cm depth in October 2014. At this time, use of FGD gypsum regardless of amendment had decreased soil organic matter in both depths by approximately 27%. At 0- to 15-cm soil depth, the co-application of FGD gypsum decreased (P < 0.05) soil test K by approximately 26 mg kg-1, and increased SO4-S by 229 mg kg-1, soluble salts by 0.48 dS m-1, and cation exchange capacity by 2.8 cmol (+) kg-1. A significant (P < 0.01) year x fertility amendment interaction was detected for bermudagrass dry matter (DM) yield. Regardless of year, DM yield averaged across FGD gypsum treatments was greater (P<0.05) with poultry litter than either swine compost or NPK fertilizer. The height/diameter ratio of loblolly pine was least with poultry litter (P < 0.10), suggesting these trees have improved stability. Repeatedly applying poultry litter improved soil quality and plant growth parameters in a respread area.