Submitted to: Nutrient Cycling in Agroecosystems
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/1/2011
Publication Date: 5/1/2011
Citation: Johnson, K.N., Kleinman, P.J.A., Beegle, D., Elliott, H., Saporito, L.S. 2011. Effect of dairy manure slurry application in a no-till system on phosphorus runoff. Nutrient Cycling in Agroecosystems. DOI: 10.1007/s10705-011-9422-8. Interpretive Summary: Broadcasting manure to no-till soils poses a risk to water quality as surface applied manure readily washes off, enriching surface waters with nutrients that create algal blooms. We tested an array of manure application technologies to determine how well they limited phosphorus runoff from no-till soils. Aeration of soil prior to manure application and shallow injection of manure into the soil lowered phosphorus losses by more than 94% relative to conventional surface application. Results point to significant opportunities to protect water quality with new manure application technologies.
Technical Abstract: Incorporation of manure under reduced tillage conditions remains a challenge in the northeastern U.S. New technologies to inject or improve manure incorporation are available but their agronomic and environmental benefits have not been quantified. This study evaluated the effects of six manure application methods on phosphorus loss in runoff: broadcasting manure with and without incorporation by tillage; shallow disk injection; banded application and aeration; pressurized injection, and control (no manure). Research was conducted over a two year period in central Pennsylvania on a well-drained Hagerstown silt loam (fine, mixed, semiactive, mesic Typic Hapludalf) under corn (Zea mays L.) production. Approximately 72 hrs after dairy manure application (56,000 L**ha), a single event rainfall simulation (68 mm**h) was conducted in triplicate on 10 x 13 m plots. Trends in total P losses varied between years and treatments, with aeration consistently having the lowest losses due to improved rainwater infiltration. In 2006, dry conditions resulted in little runoff, with no apparent benefit from manure incorporation to P losses. However, in 2007 when antecedent moisture and runoff volumes were relatively high, direct incorporation methods (injection and aeration) reduced total P losses relative to broadcast, but incorporation by tillage was not significantly different due to elevated erosion. Injection methods were effective at lowering manure P on the soil surface without increasing erosion. Overall, manure incorporation can be effective in controlling runoff P losses but results vary over time.