title: Evaluating aeration techniques for decreasing phosphorus export from grasslands receiving manure.
abstract: Because surface-applied manures can contribute to phosphorus (P) in runoff, we examined mechanical aeration of grasslands for reducing P transport by increasing infiltration of rainfall and binding of P with soil minerals. The effects of three aeration treatments and a control (aeration with cores, continuous-furrow "no-till" disk aeration perpendicular to the slope, slit aeration with tines, and no aeration treatment) on the export of total suspended solids, total Kjeldahl P (TKP), total dissolved P (TDP), dissolved reactive P (DRP), and bioavailable P (BAP) in runoff from grasslands with three manure treatments (broiler litter, dairy slurry, and no manure) were examined before and after simulated compaction by cattle. Plots (0.75 x 2 m) were established on a Cecil soil series with mixed tall fescue (Festuca arundinacea Schreb.)-bermudagrass [Cynodon dactylon (L.) Pers.] vegetation on 8 to 12% slopes. Manures were applied at a target rate of 30 kg P ha(-1), and simulated rainfall was applied at a rate of 85 mm h(-1). Although the impact of aeration type on P export varied before and after simulated compaction, overall results indicated that core aeration has the greatest potential for reducing P losses. Export of TKP was reduced by 55%, TDP by 62%, DRP by 61%, total BAP by 54%, and dissolved BAP by 57% on core-aerated plots with applied broiler litter as compared with the control (p < 0.05). Core and no-till disk aeration also showed potential for reducing P export from applied dairy slurry (p < 0.10). Given that Cecil soil is common in pastures receiving broiler litter in the Southern Piedmont, our results indicate that pairing core aeration of these pastures with litter application could have a widespread impact on surface water quality.
authors.affiliation: Univ. of Georgia, Dep. of Crop and Soil Sciences, 3111 Miller Plant Sciences Bldg., Athens, GA 30602, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Butler
authors.forename: Dorcas H
authors.initials: DH
authors.lastname: Franklin
authors.forename: Miguel L
authors.initials: ML
authors.lastname: Cabrera
authors.forename: Armando S
authors.initials: AS
authors.lastname: Tasistro
authors.forename: Kang
authors.initials: K
authors.lastname: Xia
authors.forename: Larry T
authors.initials: LT
authors.lastname: West
mesh_terms: D000388:Air; D001682:Biological Availability; D005308:Fertilizers; D008372:Manure; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D006109:Poaceae / Q000378:metabolism; D011891:Rain
chemical_list: D005308:Fertilizers; D008372:Manure; D010758:Phosphorus