|Saporito, Louis - Lou|
|Way, Thomas - Tom|
Submitted to: Journal of Environmental Quality
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/25/2010
Publication Date: 3/20/2011
Citation: Kibet, L.C., Allen, A.L., Kleinman, P.J.A., Feyereisen, G.W., Church, C., Saporito, L.S., Way, T.R. 2011. Phosphorus runoff losses from a no-till coastal plain soil with surface and subsurface-applied poultry litter. Journal of Environmental Quality. 40:412-420. DOI: 10/2134/jeq2010.0161. Interpretive Summary: Land application of poultry litter to no-till soils of the Delmarva Peninsula is a key concern to the Chesapeake Bay as phosphorus in litter readily washes off no-till soils. We investigated the effects of a new USDA technology that places litter below the surface of no-till soils on phosphorus losses in runoff. Compared with conventional application methods, the USDA applicator significantly lowered phosphorus loss in runoff events that occurred shortly after litter was applied. The study also found that modifications to the new applicator are needed to ensure that these short-term benefits carry over to the long-term.
Technical Abstract: The application of poultry litter to soils is a water quality concern on the Delmarva Peninsula, as runoff contributes phosphorus (P) to the eutrophic Chesapeake Bay. This study compared a new subsurface applicator for poultry litter with conventional surface application and tillage incorporation of litter on a coastal plain soil under no-till management. Monolith lysimeters (61 x 61 x 61 cm) were collected immediately after litter application and subjected to rainfall simulation (61 mm/h, 1 h) 15 and 42 days later. Subsurface application of litter (1.90 kg/ha) significantly lowered total P losses in runoff by about 75 percent during the first simulation as compared with surface application (4.78 kg/ha). Losses of P with subsurface application were not significantly different from disked litter or an unamended control. However, in the second simulation 27 days later, total P losses did not differ significantly between surface and subsurface litter treatments, and were at least 2-fold greater than losses from the disked and control treatments. A rising water table in the second simulation likely transported dissolved forms of P in subsurface applied litter to the soil surface, exacerbating runoff P losses. Thus, subsurface application of litter did not significantly decrease cumulative losses of P in surface runoff relative to surface applied litter, even though disking the litter to incorporate it into soil did. Results confirm the near-term benefits of subsurface litter application observed elsewhere, but highlight the modifying effect of soil hydrology on this technology’s ability to minimize P loss in runoff.