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United States Department of Agriculture

Agricultural Research Service

Research Project: New Subsurface Applicator for Dry Litter

Location: Dale Bumpers Small Farms Research Center

2012 Annual Report


1a.Objectives (from AD-416):
Introduce and transfer technology for subsurface application of dry manure to key sub-watersheds of the Chesapeake Bay Watershed, simultaneously addressing agricultural production limitations and water-quality concerns associated with dry manure application in reduced tillage systems.


1b.Approach (from AD-416):
The project will be conducted in seven sub-watersheds of the Chesapeake Bay Watershed to test and deliver subsurface application technology to farmers, and will serve as a centerpiece of coordinated nutrient management efforts. In each sub-watershed, local team leaders will work with conservation districts, extension, and private-sector partners to test and refine the performance of a prototype subsurface applicator. This tractor-drawn implement, known as the "ARS Poultry Litter Subsurfer," will be tested in field trials on commercial farms and research stations to quantify and demonstrate agronomic and environmental benefits. The project will be conducted over 27 months, with the first 6 months primarily dedicated to manufacturing the prototype applicators and preparation of other project materials, while the bulk of field activities and technology transfer will occur in the final 21 months. Working with the applicator manufacturer, adjustments will be made to individual applicators to address conditions in each of the sub-watersheds to ensure the best possible performance. Field trials will be initiated on three to five farms per sub-watershed to test the performance of the applicator relative to two conventional options: surface application and no application. With farmer participation, N- and P-based rates of dry manure application will be evaluated by monitoring yield, soil, and plant-tissue quality. The impact of subsurface application on environmental variables will be quantified using a two-phased approach. In the first phase, loss of nutrients through runoff and volatilization will be directly measured and compared for subsurface application and conventional surface application, generating data on sediment and nutrient loads as well as ammonia-N emissions to the atmosphere. In the second phase, measurements from the first phase will be used to develop efficiency factors for the Chesapeake Bay Watershed. Technology transfer is the ultimate goal of this project, and all major agricultural stakeholders in the sub-watersheds will be engaged in the process. Outreach activities aimed at organizing interested parties will be initiated in each of the project sub-watersheds. A variety of informational media will be used to garner interest/support, including brochures, a web page, and informational video. Inaugural meetings will transition into on-farm trials, demonstrations, field days, and equipment loans. Working with extension, SWCD, state and federal programs, recommendations will be developed for use of the subsurface applicator by farmers.


3.Progress Report:

Construction of the four new prototype subsurface applicators (Subsurfers) for this project has been completed, and the Subsurfers have been delivered to Pennsylvania State University, Virginia Tech University, Cornell University, and University of Delaware (shared use with University of Maryland). Discussions were held with cooperating agencies (Extension Service, Conservation Districts, USDA-NRCS) and potential farmer cooperators to select field sites for Subsurfer research. Farms for demonstration and research projects were identified in the cooperating states. Subsurfers have been used to establish research plots at several field sites on commercial farms and/or research stations in Pennsylvania, Virginia, New York, Delaware, and Maryland to determine the environmental and production effects of subsurface application technology. In Maryland, the Subsurfer was used to treat replicated plots with three rates of subsurface-applied poultry litter at two different sites for a total of 90 treated acres. Two other sites near Chrisfield, Maryland, were equipped with automated samplers monitoring ditch flow from each site where the Subsurfer applied poultry litter. Field trials were established in Princess Anne, Maryland, to assess the effects of subsurface application on corn grain yield, surface runoff, and nutrient leaching. In Pennsylvania, field trials were established on six commercial farms to determine effects of Subsurfer application of broiler litter and pit-dried layer manure. At Pennsylvania State University, a field-scale lysimeter site has been developed to evaluate nutrient fate in cropping systems that include the subsurface application technology. The Virginia Subsurfer was used successfully to install replicated field plots with two rates of poultry litter on orchard grass and no-till corn to study effects on runoff, nutrient loss, crop yield, and crop quality. Subsurfer testing in the Chesapeake Bay Watershed has confirmed that the Subsurfer can effectively place dry manures from a variety of sources under the soil surface, with minimal disturbance of soil and residue cover. Project investigators have documented benefits to nutrient conservation, water quality, air quality, and crop yield, and also have identified areas in which the Subsurfer can be improved. As a result, project personnel have been in consultation with the company holding a license to manufacture the Subsurfer, to discuss design modifications to further improve the technology. Considerable interest in the Subsurfer technology has been generated through numerous extension activities. A Subsurfer was featured at Pennsylvania State University Ag Progress Days which attracted approximately 40,000 visitors, and was demonstrated using pelletized poultry litter for science students and media representatives at William Penn High School. Several of the prototypes have been demonstrated at extension field days in Pennsylvania, Maryland, Delaware, Virginia, North Carolina, and New York. Pennsylvania State University has also developed a recruitment video for the project, which has been distributed by CD and on the internet (http://www.youtube.com/watch?v=V6IHAS4Ng6o).


Last Modified: 4/21/2014
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