The ManureMap toolbox is an ACPF-compatible tool that provides a method to spatially characterize the application of manure nutrients from their point of production to proximal cropland in agricultural landscapes.
The tools are designed to utilize field boundaries and land use information derived from the Agricultural Conservation Planning Framework (ACPF). Tool outputs include an identification of fields likely to receive manure based on crop nutrient need and spatial proximity to the point of manure production, as well as an estimate of the land base required and haul distances associated with each operation.
While the ACPF was developed to run at the scale of the Hydrologic Unit Code (HUC) 12 watershed, characterizing manure application at this scale can result in significant bias due to the movement of manure across watershed boundaries. It is therefore recommended to run the ManureMap tools at a regional scale, such as a larger hydrologic unit or statewide.
DOWNLOAD THE TOOL
The newly released beta version of the ManureMap toolbox is currently available and can be applied to any geographic region for which input data are available Before you dive in, be sure to view this slideset which provides an overview of the toolbox in action. A detailed user manual is also provided with a download of the toolbox.
HOW IT WORKS
The tool provides several different approaches to define a nutrient need for each field, which determines the rate at which manure is applied. These options include:
- Nitrogen (N) fertilizer recommendations
- Nitrogen (N) removal
- Phosphorus (P) removal
Lookup tables included with a download of the ManureMap toolbox provide default values for N fertilizer recommendations and nutrient (N and P) removal for each of the twenty-two crops that can currently be modeled.
Manure application may also be modeled over different timeframes, including:
- Across a Rotation. Manure is applied to meet field nutrient needs over the course of a crop rotation. This is defined by an average annual nutrient need for each field.
- Single Year. Manure is applied to meet field nutrient needs for a single year at a time for several years in succession. This is defined by an annual nutrient need for each field. Model results from several years are then summarized across a crop rotation. The primary benefit of this approach is that it enables residual manure N (second year availability of manure N) to be tracked and appropriately credited year to year.
Manure application to fields is based on spatial proximity. The process for spatially allocating manure was originally published in a peer-reviewed journal article in 2020 and can be accessed here.
The process for spatially allocating manure runs as a series of manure application loops. The initial loop begins by selecting, for each feedlot provided, the single nearest field with a nutrient need greater than zero. Each feedlot can apply manure to a single field during any given loop. Using each feedlot as a source of available nutrients, manure application is simulated by decrementing the amount of nutrients required by the field from the source feedlot. Accounting is performed to track how much of each nutrient is applied during each loop of manure application. If a feedlot can meet the entire nutrient requirements of a field, that amount of the corresponding nutrient is subtracted from the amount available from the feedlot. Once the total nutrient requirement of a field has been met, the field is no longer eligible to receive manure from any feedlot.
Alternatively, if a feedlot is only able to partially supply the nutrient needs of a field, the new nutrient requirement of the field becomes the initial requirement minus what was applied during the current loop. Once a feedlot has disposed of the entirety of its manure, it is removed from the analysis. During each application loop, the single nearest field that is still eligible to receive manure from any remaining feedlot is selected.
DATA INPUTS
The tool requires two data inputs to be provided by the user, as described below.
- Field boundaries and land use information in the same data structure as the ACPF. Any user-generated field boundary polygons can serve as a starting point for this without any attribution. To obtain the required data structure for use with the ManureMap toolbox, the “Update Edited Field Boundaries” tool within the ACPF toolbox must be run. The “Update Edited Field Boundaries” tool can be run at scales larger than the HUC-12 watershed, such as regional or statewide. More details on running this tool can be found in the user manual that is provided with a download of the ACPF toolbox.
Alternatively, several statewide datasets of ACPF field boundaries and land use information (including Minnesota, Iowa, Illinois, Nebraska, and Wisconsin) have been published on the USDA Ag Data Commons and can be accessed through the search term “ACPF”.
The user may also wish to contact the ACPF National HUB to collaborate and receive support for obtaining field boundary and land use datasets at scales larger than the HUC-12 watershed.
- Point-level dataset of animal feeding operations with crop-available manure N and P. It is expected that the user provides not only point locations of animal feeding operations, but also crop available manure nutrients (N and P) from each location. A minimum of three attribute fields (optionally 4) should exist within the provided point layer. There are no required naming conventions for the following field names, but they should represent:
- A unique identifier for each animal feeding operation (required)
- Lbs of Year One crop-available manure N (lbs) (required)
- Lbs of Year Two crop-available manure N (lbs) (optional)
- Lbs of crop-available manure P (elemental P, not P205) (required)
The ManureMap toolbox does not currently provide a method for the estimation of crop available manure nutrients from each animal feeding operation. This is a complex process that is compounded by the fact that data availability on feedlot location and type and number of animals housed varies significantly from state to state. In areas where data is readily available, assumptions must be made regarding manure recoverability and losses during storage, handling, and application. While book values are often relied upon to make these assumptions, these can vary significantly from actual manure nutrient content data that is collected by labs across the country.
TOOL OUTPUTS
Tool outputs includes a manure processed field boundary feature class and an Animal Feeding Operation (AFO) Statistics Table. The output manure processed field boundary feature class includes information on field nutrient need, the percent of field nutrient need met by manure nutrients, and the acres upon which manure application was modeled (shown in Image 1). The output AFO statistics table includes information on the number of fields where manure was applied and the maximum travel distance for each operation.
The ManureMap Toolbox was developed by the United States Department of Agriculture (USDA) Agricultural Research Service (ARS) in collaboration with the USDA Long-Term Agroecosystem Research (LTAR) network and the Agricultural Conservation Planning Framework (ACPF) National Hub.
Funding for development of new tools and capabilities for the ACPF is provided by USDA Natural Resource Conservation Service (NRCS) Conservation Effects Assessment Project- Watershed Assessment Studies under the ACPF Enhancement Project, NRCS Interagency Agreement # NRC21IRA0010883 with USDA ARS.