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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #332390
Title: Manure storage capacity and application timing influence watershed-level nutrient losses

Author
item LIU, JIAN - Pennsylvania State University
item Veith, Tameria - Tamie
item Kleinman, Peter
item BEEGLE, DOUGLAS - Pennsylvania State University
item COLLICK, AMY - University Of Maryland Eastern Shore (UMES)
item WELD, JENNIFER - Pennsylvania State University

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/2/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary: Phosphorus loss from land spreading of manure can lead to pollution of surface water. This has become a concern in the Chesapeake Bay Region. Manure storage capacities on the farm affect manure application timings, which in turn affect phosphorus loss from land to water. Scientists with USDA-ARS, Pennsylvania State University, and University of Maryland Eastern Shore carried out a model study to assess manure storage and application timing on phosphorus losses in a Pennsylvania watershed. While 12-month storage, i.e., spreading of manure all in spring, reduced total amounts of phosphorus losses to the stream compared to 6-month and 3-month storage, it led to great peaks of phosphorus losses in spring. Results point to the need to assess trade-offs associated with change in manure storage capacities in the region.

Technical Abstract: Current concerns over water quality requires best management practices for land-applied manure. One important strategy is to apply manure at right timing, which though is often greatly affected by manure generation and storage capacities in a given watershed. This study was to test the hypotheses: (1) different distributions of manure application timings within a year as determined by manure storage capacities result in similar amounts of annual nutrient losses, but they present different temporal dynamics; (2) winter manure applications increase risk of nutrient losses compared with applications in other seasons; and (3) effects of manure application timing on water quality vary with cropping systems. We use the Soil and Water Assessment Tool (SWAT) to assess effects of manure application timing on phosphorus (P) and nitrogen (N) losses from a 7.3 km2 watershed located in the Ridge and Valley physiographic region of south central Pennsylvania. The study watershed has been intensively monitored by the USDA-ARS since 1968, and specific field management practices are recorded since 1999. Thus, long-term data (climate, hydrology, water quality, soil, land use, and nutrient management) are available and were used to create a detailed SWAT model of the watershed. Our simulation scenarios include four manure application timings (historically-reported applications by the farmer; spring application; spring and fall applications; and spring, summer, fall, and winter applications), representing existing, 12-month, 6-month, and 3-month manure storage capacities, respectively. Seasonal and annual nutrient losses are compared among scenarios and between cropping systems to assess the range of losses predicted and the degree of environmental benefit achieved by moving to more restrictive application. The results will provide scientific support for decision makers regarding the impacts of manure storage capacities and application timing on seasonal risk-levels of nutrient losses from the watershed.