computer poultry litter
TRANSCRIPT
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c o m p u t e r s a n d e l e c t r o n i c s i n a g r i c u l t u r e 6 4 ( 2 0 0 8 ) 212224
a v a i l a bl e a t w w w . s c i en c e d i r e c t . co m
j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c o m p a g
A comprehensive GIS-based poultry litter management
system for nutrient management planning and litter
transportation
M.S. Kang a,, P. Srivastava b, T. Tyson b, J.P. Fulton b, W.F. Owsley c, K.H. Yoo b
a Rural Systems Engineering, Seoul National University, Seoul, Republic of Koreab Biosystems Engineering, 200 Corley Building, Auburn University, Auburn, AL, USAc Animal Science, Auburn University, Auburn, AL, USA
a r t i c l e i n f o
Article history:
Received 28 August 2007
Received in revised form
21 April 2008
Accepted 8 May 2008
Keywords:
Broiler litter
Poultry litter
Decision support system
Comprehensive nutrient
management plan
Transportation analysis
Geographic information system
a b s t r a c t
Confined poultry (broiler) production in Alabama results in about 1.8 million tons of lit-
ter annually. Because poultry production mainly occurs in the Appalachian Plateau region
of north Alabama, this region suffers from excessive land application of litter, resulting in
buildup of phosphorus (P) in soils and runoff of pathogens and P from land-applied areas.
Conversely, the Black Belt region of south-central Alabama suffers from depressed agri-
cultural economy because of poor soil fertility. In order to achieve optimal poultry litter
management in Alabama, litter produced in the concentrated production areas within the
Appalachian Plateau region mustbe optimallydistributed in this region or transported south
for utilization in the Black Belt region. Hence, a comprehensive system to provide improved
waste management strategies (optimal land application and transportation) for sustainable
on- and off-farm litter utilization in Alabama is needed. The primary focus of this study
was to develop a comprehensive, geographic information system (GIS)-integrated poultry
litter decision support system (PLDSS) for on- and off-farm management of poultry litter in
the Appalachian Plateau and Black Belt regions of Alabama. The PLDSS is a user-friendly,
comprehensive system that supports nutrient management planning, transportation anal-
ysis, anddata management for poultry litter management using ArcObjects, Visual Basic for
Applications (VBA), and Network Analyst in ArcGIS. Important functional components and
analytical capability of ArcGIS 9.1 were implemented in several sets of customized tools.
Because the PLDSS allows efficient development of nutrient management plan, it can help
to reduce over-application of poultry litter. Also, through PLDSS transportation analysis,
the litter can be optimally transported to nutrient deficit areas. Therefore, the PLDSS will
helppoultry producerswith optimal, cost-effectiveand environmentallysound poultry litter
management in Alabama.
2008 Elsevier B.V. All rights reserved.
1. Introduction
Alabama consistently ranks in top three, with Arkansas and
Georgia, in broiler production. Currently, more than 4000 poul-
Corresponding author. Tel.: +82 2 880 4582; fax: +82 2 873 2087.E-mail address: [email protected] (M.S. Kang).
try growers (out of 25,000 in US) operate about 12,000 broiler
houses (out of about 85,000 in US) in Alabama. In 2004,
Alabama broiler producers marketed more than 1 billion birds
with receipts of $2.41 billion (an increase of 31% over the
0168-1699/$ see front matter 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.compag.2008.05.013
mailto:[email protected]://dx.doi.org/10.1016/j.compag.2008.05.013http://dx.doi.org/10.1016/j.compag.2008.05.013mailto:[email protected] -
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previous year) and accounted for nearly 44% of total farm
and forestry receipts (USDA-NASS, 2005). However, confined
broiler (referredto as poultry hereafter)productionin Alabama
alone results in about 1.8 million tons of poultry litter annu-
ally, containing high levels of nitrogen (N), phosphorus (P),
pathogens, and other potential contaminants (e.g., Arsenic,
Copper, and Zinc) (Kingery et al., 1994). Land application of
the large amount of litter generated from poultry productionis confined primarily to relatively small areas of perennial tall
fescue pastureland in the Appalachian Plateau region of north
Alabama.
Because application of poultry litter to pastures and row
crops serves as a cheap alternative to commercial fertilizer,
over the years, application of poultry litter based on agro-
nomic N requirements of forage has resulted in soil P buildup
because of high P to N ratio in poultry litter. Even though P is
an essential nutrient for plant growth, runoff of P can accel-
erate eutrophication, resulting in severe impairment of water
bodies that support aquatic, recreational and drinking water
uses (Carpenter et al., 1998; Daniel et al., 1998). Additionally,
nationwide, P losses from agricultural areas have emerged asa critical Total Maximum Daily Load (TMDL) issue. In addi-
tion to P, other waterquality issues(e.g., pathogens) associated
with massive amount of litterproduced each year threaten the
sustainability of poultry industry in the Appalachian Plateau
region.
In order to minimize discharge of pollutants from land-
applied poultry litter, Alabamas National Pollutant Discharge
Elimination System (NPDES) rules for Animal Feeding Opera-
tions (AFOs) requiresall AFOs to implement best management
practices (BMPs) to protect water quality. While the rules
for the larger Confined Animal Feeding Operations (CAFOs)
require a registration procedure and a Natural Resources Con-
servation Service (NRCS) approved waste management plan,all size AFOs are required to implement BMPs (Mitchell and
Tyson, 2001). A comprehensive nutrient management plan
(CNMP) and a phosphorus (P)-Index is a way to help meet BMP
requirements for AFOs.
Contrary to the Appalachian Plateau region which suf-
fers from excessive amount of nutrients in the form of
poultry litter, the Black Belt region located in south-central
Alabama suffers from depressed agricultural economy that
stems from poor soil fertility in pasture, hayfields, and row
crops. Also, intensive row crop producing regions such as
the nearby Tennessee Valley region use very little poultry
litter as an alternative to commercial fertilizers in spite of
extensive research which has demonstrated its value for
cotton, corn, and other crops (Mitchell and Donald, 1995;
Sims, 1987; Wood et al., 1993). In order to achieve an opti-
mal poultry litter management in Alabama, poultry litter
produced in the concentrated production areas within the
Appalachian Plateau region must be optimally distributed
and land applied in this region or should be transported
south for utilization in the Black Belt region (Kang et al.,
2006). Important poultry litter management issues particu-
lar to Alabama (which are similar to issues in other poultry
producing states) include limited use of nutrient manage-
ment planning and P-Index by farmers, over-application of
litter to small areas near the production facility, and lack of
transportation infrastructure for transportation of excess lit-
ter to nutrient deficit areas. Thus, to address many of these
issues (i.e., to help Certified Animal Waste Vendors (CAWVs)
and County Conservation District staff to efficiently develop
a CNMP and a P-Index for AFOs and CAFOs, and to transport
excess litter, for a cost-effective and environmentally sound
management of poultry litter) a comprehensive decision sup-
port system (DSS) is needed. A CAWV is a person who is
certified to transport and land apply (on another farm afterdeveloping a nutrient management plan and P-Index) excess
litter produced at a particular poultry facility. Further, since
CNMP, P-Index, and transportation analysis are all spatial in
nature, integration of such a comprehensive DSS with GIS is a
must.
A DSS has been defined in many different ways, but
it can be regarded, in general, as an interactive, flexible,
and adaptable computer-based information system especially
developed for supporting the recognition and solution of a
complex, poorly structured or unstructured, strategic manage-
ment problem for improved decision-making (Berlekamp et
al., 2007). A DSS often become spatial decision system (SDSS)
by integrating functionalities or coupling with existing GIStools. Recent studies related to environmental SDSSs have
been mostly limited to land and water quality management
(Choi et al., 2005; Berlekamp et al., 2007; Dorner et al., 2007;
Reichert et al., 2007; Rudner et al., 2007; Schluter and Ruger,
2007; Ochola and Kerkides, 2004). An environmental SDSS
for poultry litter management often consists of various cou-
pled environmental models, databases and assessment tools,
which are integrated under a graphical user interface (GUI),
often realized by using spatial data management functionali-
ties provided by a GIS.
Currently, a number of spatial and non-spatial animal
waste/nutrient management planning tools are being devel-
oped and/or supported. Examples of these tools includeManure Management Planner (MMP) developed by the Purdue
University(http://www.agry.purdue.edu/mmp/ ); Spatial Nutri-
ent Management Planner (SNMP) developed by the University
of Missouri (http://www.cares.missouri.edu/snmp/); NRCS
Animal Waste Management Software (http://www.wcc.nrcs.
usda.gov/awm/); Purdues web-based Nutrient Manage-
ment Availability Calculator (http://www.agry.purdue.edu/
mmp/); AFOPro (De et al., 2004; http://www.esri.sc.edu/
Projects/usda/milestone.asp); AFOWizard (http://ip.research.
sc.edu/catalog/00299.htm); Crop Nutrient Tool (http://npk.
nrcs.usda.gov/nutrient body.html); WebGro (Paz et al., 2004);
and web-based conservation planning worksheets (Steiner et
al., 2006). In some studies on poultry litter, the environmentalimplications of excessive nutrients (Kingery et al., 1994; Ritter,
2000; Cabrera and Sims, 2000) and the value of poultry litter
as a fertilizer (Mitchell and Donald, 1995; Bukenya et al., 1999;
Bagley and Evans, 1998; McKinley et al., 2000; Binford et al.,
2001; Mitchell and Tu, 2005) have been quantified. A number
of tools or systems have been, or are being, developed in
response to the regulations mandating CNMP. However, appli-
cation of current tools in Alabama is limited because quite
often these tools are difficult to use County Conservation
District staff, CAWVs, and farmers; do not support record
keeping (to demonstrate compliance) required by Alabama
land application of animal waste regulations; and do not
integrate GIS-based transportation analysis for efficient,
http://dx.doi.org/10.1016/j.compag.2008.05.013http://dx.doi.org/10.1016/j.compag.2008.05.013http://dx.doi.org/10.1016/j.compag.2008.05.013http://dx.doi.org/10.1016/j.compag.2008.05.013http://www.agry.purdue.edu/mmp/http://www.cares.missouri.edu/snmp/http://www.wcc.nrcs.usda.gov/awm/http://www.wcc.nrcs.usda.gov/awm/http://www.agry.purdue.edu/mmp/http://www.agry.purdue.edu/mmp/http://www.esri.sc.edu/Projects/usda/milestone.asphttp://www.esri.sc.edu/Projects/usda/milestone.asphttp://ip.research.sc.edu/catalog/00299.htmhttp://ip.research.sc.edu/catalog/00299.htmhttp://npk.nrcs.usda.gov/nutrient_body.htmlhttp://npk.nrcs.usda.gov/nutrient_body.htmlhttp://npk.nrcs.usda.gov/nutrient_body.htmlhttp://npk.nrcs.usda.gov/nutrient_body.htmlhttp://ip.research.sc.edu/catalog/00299.htmhttp://ip.research.sc.edu/catalog/00299.htmhttp://www.esri.sc.edu/Projects/usda/milestone.asphttp://www.esri.sc.edu/Projects/usda/milestone.asphttp://www.agry.purdue.edu/mmp/http://www.agry.purdue.edu/mmp/http://www.wcc.nrcs.usda.gov/awm/http://www.wcc.nrcs.usda.gov/awm/http://www.cares.missouri.edu/snmp/http://www.agry.purdue.edu/mmp/ -
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cost-effective, and environmentally sound regional/statewide
management of poultry litter.
Hence, the objective of this study was to develop a com-
prehensive GIS-based poultry litter decision support system
(PLDSS) to assist with nutrient managementplanningfor AFOs
and CAFOs, assist with record keeping of litter application
activities, and to provide transportation analysis functions
for optimal, cost-effective and environmentally sound, poul-trylittermanagement in Alabama. Such a system will not only
help sustain and enhance poultry industry in the Appalachian
Plateau region, but will also help row crop agriculture to grow
in the Black Belt region of Alabama.
2. Development of the PLDSS
DSS are computer-based systems that share several key
characteristics, including (1) assisting users in their decision-
making in a flexible and interactive manner; (2) solving all
classes of problems, including ill-structured ones; (3) hav-
ing a powerful and user-friendly interface; and (4) having adata analysis and modeling engine (Franck et al., 2000). A
comprehensive GIS-based PLDSS for on- and off-farm usage
of poultry litter in the Appalachian Plateau and Black Belt
regions of Alabama was developed for potential use by County
Conservation District staffs who have access to ArcGIS sys-
tem.
The user interface and the analysis routines in PLDSS were
developed by programming the Visual Basic for Applications
(VBA) with ArcObjects available in ArcGIS. Important func-
tional components and the analytical capability of ArcGIS 9.1
were implemented in several sets of customized and user-
friendly tools. The VBA development environment consists of
two primary tools: the customized dialog box for interactivelymodifying the user interface and the Visual Basic Editor for
creating user forms and for writing, testing, and debugging
Visual Basic code. This system incorporates a poultry litter
database management system (PLDBMS) that was developed
using MySQL 5.0 for the efficient management of poultry litter
data. Since ArcGIS supports VBA for integrated macro devel-
opment and MySQL is one of the worlds most popular open
source database, they were used to development of PLDSS.
The systems GUI allows users with limited computer
knowledge to use the PLDSS by customizing its applications.
For example, for the users convenience, the GUI provides an
instrumental operating system with pull-down menus. Fur-
thermore, it aids the users decision-making process regardingpoultry litter management, transportation, and evaluation by
displaying the projected results of various alternatives in the
form of graphical images, tables, and charts. To make the
system user-friendly, this system was designed to provide
detailed help on theinput parameters byclicking on the ques-
tion box buttons in the sub-modules input windows. Further,
in order to facilitate the process of determining the ideal
input parameters, the system was designed so that placing
the cursor on the input parameters input window the system
suggests default value for the applicable parameter.
The PLDSS has four modules (Fig. 1), namely, the CNMP
Decision Module, the Transportation Analysis Module, the
CNMP Assessment Module, and the PLDBMS Module. More
detail on the conceptual framework of this system can be
found in Kang et al.(2006). Thispaper presents detailed imple-
mentation of PLDSS in ArcGIS using ArcObjects, VBA, and
Network Analyst.
2.1. CNMP Decision Module
The CNMPDecision Moduleof the PLDSS wasdeveloped basedon the methodology proposed by the Alabama Cooperative
Extension System (ACES; Mitchell and Tyson, 2001). The ACES
plan is composed of five steps: (1) estimate poultry litter and
compost produced; (2) determine the nutrient value of the
poultry litter and compost based on quantity and availability
of nutrients in the litter; (3) map and calculate the spreadable
land area available for application; (4) determine the target
crop and nutrient needs, including whether poultry litter is
applied based on a nitrogen limit or on phosphorus removal
by the crop; and (5) determine uses for excess litter that can-
not be used on thefarmwhere it is produced and CAWV needs
(Miles and Bock, 2006; Kang et al., 2006).
The CNMP Decision Module of the PLDSS consists of threesub-modules: (1) Farm Operation, a sub-module containing
general information regarding the AFOs that calculates total
litter produced and the total nutrient value of produced lit-
ter; (2) Fields, a sub-module that calculates the P-Index and
nutrient needs of a cropland/hay/pasture field; and (3) CNMP
Application, a sub-module that determines the amount of lit-
ter to be applied to the field and the excess litter (Fig. 1). All
of the data calculated and generated by the CNMP Module
are stored and managed in PLDSSs database, named PLDBMS
(discussed later).
2.1.1. Comprehensive nutrient management plan (CNMP)
The United States Department of Agriculture (USDA) and theUnited States Environmental Protection Agency (EPA) have
released a Unified National Strategy for AFOs. This strat-
egy represents the USDAs and EPAs plan for addressing
the water quality and public health concerns arising from
AFOs. The cornerstone of the strategy is the expectation
that all AFOs will develop and implement a site-specific
CNMP.
Due to the limited technical staff available, the states
County Conservation District staffs are only able to develop
CNMPs/P-Index for CAFOs. The owners/operators of the more
than 4000 AFOs in Alabama receive little assistance. Since
AFOs are not required by law to have a CNMP in place,
CAWVs and AFO owners/operators are often not interested ina comprehensive plan, but prefer a simple plan that works.
In an attempt to address this problem, the CNMP Decision
Module will simplify development of CNMP and P-Index for
County Conservation District staff. Further, this will allow
CAWVs to develop CNMP and P-Index themselves with assis-
tance from County Conservation District staff. Note that in
Alabama only CAWVs are certified to transport poultry litter
in accordance with the Alabama Department of Environmen-
tal Managements (ADEM) AFOs/CAFOs rules. AFOs are small
operations, while CAFOs are big animal feeding operations.
CAFOs are AFOs with 1000 animal (feed cattle) unit equiv-
alency or more. For poultry (broiler) production this means
about 100,000 chickens. Federal regulations require CAFOs to
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Fig. 1 Overall conceptual architecture of the poultry litter decision support system (PLDSS).
carry a permit and to develop detailed nutrient management
plans designed to keep animal waste from contaminating sur-
face and groundwater.
2.1.2. Estimation of poultry litter produced and nutrient
value
Annual production estimates for poultry litter and compost
are calculated by multiplying the market weight of birds pro-
duced each year by the production rate, which is estimated to
be about 0.5 pounds of poultry litter per market weight pound
of bird produced, as suggested by Auburn University Biosys-
tems Engineering and the Alabama poultry industry (Mitchell
and Tyson, 2001).The nutrient values of poultry litter and compost used
in this study were the average values for litter and com-
posted dead birds and were estimates of the plant available
nutrients during the first year under Alabama conditions,
as reported by ACES (Mitchell and Tyson, 2001). Avail-
able nutrients from surface-applied litter and compost were
475845 and 425845 pounds of NP2O5K2O per ton,
respectively. Note that in the case of surface-applied lit-
ter, the N value should be multiplied by 0.84 to account
for N volatilization (Mitchell and Tyson, 2001). The nutrient
removal for the targeted crop (Bermuda grass pasture) was
501243 pounds NP2O5K2O per tons (Mitchell and Tyson,
2001).
2.1.3. Determination of crop and nutrient needs for each
field
Calculating thecorrect rate of nutrient needs to applyis impor-
tant to prevent the buildup of excess phosphorus in soil and
the contamination of ground and surface waters. Crop and
nutrient needs in the PLDSS were determined based on the
methodology (described earlier) proposed by ACES (Mitchell
and Tyson, 2001).
To identify fields for litter and compost spreading and to
calculate spreadable acreage, the land cover classificationdata
provided by the United States Geological Survey (USGS) were
used in thissystem. Spreadable land area in the PLDSS was the
total land area in fields receiving litter minus required buffersfor property lines (see Mitchell and Tyson, 2001, for example,
determination of spreadable land area). Nutrient needs were
determined based on N limit or on P removal by the crop to
which poultry litter was applied. P application in excess of
that recommended by soil test is based on a P-Index of field
vulnerability for P runoff into surface waters.
2.1.4. Phosphorus (P)-Index
Non-point sources of agricultural P have a considerableimpact
on water quality at a watershed-scale (McDowell et al.,
2001). Out of the three management scenarios examined by
McDowell et al. (2001), the P-Index seems to be the most use-
ful. Consequently, in many states the P-Index risk rating of an
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agricultural field plays a major role in the development of a
nutrient management plan (De et al., 2004).
TheP-Indexis a toolthatis usedto assess thesite and man-
agement practices with regard to the potential risk posed by
P movement to water bodies (USDA-NRCS, 2001). The P-Index
rating indicates the specified areas (e.g., pastures) that should
benefitand thepoultry litterratesthat shouldbe applied (Kang
et al., 2006). Nutrients are applied based on two options andare modified based on theP-Index: (1) N limitbased on soil test
recommendations fromAuburn Universitys Soil Testing Labo-
ratory (http://www.ag.auburn.edu/agrn//croprecs/index.html)
and (2) anticipated crop P removal, namely, at the N rate, 3 P
removal by crop, 2P removal by crop, 1P removal by crop,
andno P applicationfor verylow/low, medium,high,veryhigh,
and extremely high vulnerability ratings, respectively. More
information about Alabamas P-Index has been provided by
Kang et al. (2006), USDA-NRCS (2001) and Mitchell and Tyson
(2001).
2.1.5. Determination of excess litter
Once the previous determinations are completed, the poultrylitter orcompost can belandapplied. Note that dead birdcom-
post was not considered for offsite transport because farmers
are required to usethe dead birdcompost on thefarmwhere it
is generated before spreading any litter. Because of the human
health issues, dead bird compost cannot be transported with-
out a special permit from the state veterinarians office of the
Alabama Department of Agriculture and Industries (ADAI). In
PLDSS, dead bird compost wasnot considered for offsitetrans-
port.
The excess litter produced is determined based on how
much litter can be reasonably applied to each field, and thus
whether the poultry farm operation can effectively use all
the nutrients in the litter in an environmentally sound man-ner. If more litter is produced than can be used, it should
be consigned to an Alabama CAWV. The assigned CAWV can
utilize the Transportation Analysis Module to find the opti-
mum way to transport litter to nutrient deficient areas in the
Appalachian Plateau or Black Belt regions of the state.
2.2. Transportation Analysis Module
The Transportation Analysis Module allows CAWVs to find
the best route to transport litter from production areas to
application areas by examining factors such as the best route,
the closest route to fields within a certain distance, and
OriginDestination matrix created using NetworkModel tool-box in ArcGIS 9.1. The workflow used by Network Analyst in
the model is the same as the workflow for Network Analyst
in ArcMap. More detail on conceptual workflow for modeling
various transportation network analyses usingthe ArcGIS Net-
workModel can be found in Kang et al.(2006). This module was
developed using VBA in conjunction with ArcObjects in ArcGIS
environment.
Currently, CAWVs are reluctant to risk transporting litter
very far from the source. Some of the reasons given for this
include cost of transportation, low value of litter, unable to
load/reload litter, storage problems, and inability to spread
litter. As mentioned earlier, this study focuses on many of
these issues because there is consensus among researchers
and practitioners that transportation of litter within the pro-
duction areas (for proper distribution and land application)
and from production areas to Black Belt and Tennessee Valley
regions is a possible solution to alleviate excess litter problem
in the Appalachian Plateau region.
2.3. CNMP Assessment Module
An important component of PLDSS is the CNMP Assessment
Module, which is composed of two sub-modules, namely, On-
Farm Application and Offsite Application. These sub-modules
are used to determine optimal uses for excess litter that can-
not be used on the farm where it is produced. Based on
all previous modules, this module determines optimal land
application, the value of poultry litter as a fertilizer, and
the transport cost including a cleanout cost. It is economi-
cally most effective to transport excess litter from a farm to
offsite based on the rank considering travel distance using
OD matrix. The results of these sub-modules are linked
and managed by the PLDBMS. According to Miles and Bock
(2006), a recent inquiryindicates thatcurrently north Alabamavendors are typically receiving about $10 per ton for land
application of litter. Thus, they assume as our base case that
vendors could deliver poultry litter for a cleanout cost of $4
per ton plus $6 per ton for hauling an average of 40 miles at
$0.15/ton-mile. These values were used to calculate transport
cost.
2.4. PLDBMS and Geodatabase Modules
A critical issue when coupling the GIS software with CNMP
and network analysis is the database that is integrated into
the spatial-temporal database model. The PLDSS procedure
generates a large volume of CNMP and GIS data. Ineffectivedata management will result in a computational bottleneck
that can seriously degrade the performance of the system.
The PLDSS offers data input, data search, data management,
analytical and geographic visualization capabilities that can
provide effective decision support. The PLDSS incorporates
two database modules, PLDBMS and Geodatabase. The unique
spatial object IDs (i.e., operation ID and field ID) from Geo-
database are used to connect the PLDBMS with Geodatabase
and models (Fig. 2).
The PLDBMS was developed for the efficient management
of datarelatedto poultry litter. Thissystem was created bypro-
gramming MySQL, a relational database management system,
and VBA in ArcGIS. The data collected by CNMP from the userare stored and managed in a database server called MySQL
(MySQL AB, 2006). To access information from the database
server and open database connectivity (ODBC), a driver called
MySQL ODBC was used. The PLDBMS and MySQL database
server were used for pre- and post-processing the CNMP data.
PLDBMS consists of Data Management and Data Search
sub-modules. These sub-modules facilitate basic functions
for efficient data searches, storage, updates and export. The
Data Management sub-module includes an Excel-based cus-
tom record keeping tool that may meet users needs for farm
and field information, litter application, and excess litter to
CAWV. The Data Search sub-module has a function that can
search data regarding all CNMP implementation.
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Fig. 2 Overall structure of PLDBMS and Geodatabase.
The data sets were organized into a geodatabase of ArcGIS
as separate feature classes. The geodatabase is the heart of
a spatial and operational information system and provides
the central storage system that allows communication and
intermediate storage among the various subsystems (Kang
et al., 2006). This geodatabase, which is similar to the cov-
erage model, supports a model of topologically integrated
feature classes. It also extends the coverage model to supportcomplex networks, topologies, relationships among feature
classes, and other object-oriented features. Each separate fea-
ture class represents either a factor or a constraint to be used
within the PLDSS analysis. Additional attributes have been
included in some feature classes to more effectively support
the analysis.
3. Implementation of the PLDSS
3.1. Study area and geodata
Alabama is a major sink for nutrients because over 95% ofthe grain fed to Alabamas farm animals is imported (Kingery
et al., 1994). The eight leading poultry producing counties in
the state produce more than 100% of each countys P needs
in the form of poultry litter. Cullman was the leading poultry
producing county in the state, followed by DeKalb, Marshall,
and Blount during the 2003 and 2004 marketing years. The
Black Belt region was selected as the pasture area to which
the excess poultry litter should be transported. All poultry
houses, pastures, and local road information in the study area
are visible at a zoom factor of 1:800,000.
In order to identify the amount of poultry litter produced,
the broiler data for each county were obtained from the
National Agricultural Statistics Service (USDA-NASS, 2005;
Kang et al., 2006). Users can easily add and use the poultry
farm layer in the PLDSS if they have real data on location
of poultry farms. The PLDSS can easily be extended to work
with other real data due to its generic form and structure.
Forage pastures were selected for poultry litter application in
the study area, although using the CNMP the procedure can
be easily extended to other crops. The pasture polygons were
converted to a point type geodatabase for Network Analysis.The attributes such as ID number, coordinates of latitude and
longitude, and pasture area for each pasture polygon were
then calculated and added to the database table associated
with the point pasture theme.
To create the pasture data set, the land cover classification
data provided by the United States Geological Survey (USGS)
were used to reclassify pasture/hay from Landsat TM images
of the study area. The land cover data are in the form of a sin-
gle band raster image. Pasture/Hay in this study was defined
as areas of grass, legumes, or grasslegume mixtures planted
for livestock grazing or the production of seed or hay crops.
The hydrologic soil group and field slope for the calculation
of the P-Index were extracted from the soil map and digitalelevation model, respectively. To identify fields for litter and
compostspreadingand to calculate spreadablearea, a detailed
farm map such as an aerial photo of the fields to scale will
be needed. The pasture polygons were used to obtained field
boundary and spreadable area in this DSS because it is not
easy to use numerous aerial photos of each field for the whole
study area.
A geodatabase network dataset must be created to con-
duct various network analyses. A geodatabase-based network
dataset was created using the streets feature class for
Alabama. This work is conducted using ArcCatalog in ArcGIS.
More detail on the procedure of creating a geodatabase net-
work dataset can be found in ESRI (2005).
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3.2. CNMP Decision Module
Users will be able to accurately identify the spatial location
where the litter is being generated and the location of the
application fields. We now give a hypothetical example that
demonstrates the utility of the CNMP Decision Module.
Suppose a farmer with three poultry houses cleans his
chicken houses producing X amount of poultry litter. He alsohas some fields where he can apply some of the litter. He,
therefore, contacts a CAWV to handle his litter. The CAWV,
whois trained in theuse of PLDSS,locates thefarmers chicken
houses and available fields. The CAWV and users can locate
thefarms using thesubmenu to retrievean address or it is pos-
sible to select directly them on the GIS data in the PLDSS. He
then determines if the farmer already has a nutrient manage-
ment plan. If not, the CAWV uses the CNMP Decision Module
and creates a simple but effective nutrient management plan
for the farmers land. Once developed, the CAWV determines
the amount of litter that can be applied on the farmers fields
(assume this amount is Y, where Y< X). The CAWV then takes
a look at the CNMP and locates farmers that require litter.He then uses the Transportation Analysis Module to deter-
mine thecost associatedwith haulinglitter to various farmers
fields that could benefit from the litter. He evaluates various
alternatives and makes arrangements to haul the litter. Before
applying litter, the CAWV uses the P-Index/CNMP Module to
develop a nutrient management plan if the farmer (to whose
farm excess litter will be applied) does not already have one.
Once fully developed and implemented, this simple to use
PLDSS will provide numerous options for both the farmers
interested in disposing of their litter and those requiring litter.
CAWVs will also be able to perform their task much more effi-
ciently and effectively and keep an electronic record of their
activities.To demonstrate how the PLDSS can be used to help the
user efficiently develop nutrient management plans in the
concentrated poultry litter production areas for on-farm uti-
lization, the PLDSS was applied to Cullman county. To assess
the applicability of this systems CNMP, on-farm application
of the CNMP and a transportation analysis was carried out on
selected farms in the county (see Kang et al., 2006).
3.2.1. Farm Operation sub-module
The Farm Operation sub-module has three dialog boxes,
namely, General Information, Total Litter Produced, and Total
Nutrient Value.
3.2.1.1. General Information Dialog Box. The General Infor-
mation Dialog Box (Fig. 3) allows users to enter general
information regarding the CAFO/AFO owner/operator and
CAWV for which the CNMP is being prepared, including the
farm ID and contact information. All the information entered
for the selected farm is saved into the systems database. The
ID of the poultry farm randomly selected to assess the appli-
cability of this system was 161.
3.2.1.2. Total Litter Produced and Nutrient Value Dialog Boxes.
The Total Litter Produced Dialog Box (Fig. 4) allows the user
to estimate the amount of poultry litter and compost pro-
duced by the farm selected from the General Information
Dialog Box. The corresponding Total Nutrient Value Dialog
Box calculates the total nutrient value of litter. In reaching
this figure, about 20% weight loss during the composting pro-
cess and about 5% mortality were assumed. Total poultry
litter and compost produced by the selected farm were 712.5
and 89.6 ton, respectively. As shown in Fig. 5, available nutri-
ents in poultry litter and compost were 33,51741,32632,063
(NP2O5K2O, ton) and 376451984033 (NP2O5K2O, ton),respectively.
3.2.2. Fields sub-module
3.2.2.1. P-Index Dialog Box. The P-Index Dialog Box (Fig. 5)
allows users to select a field and determine the distance for
buffer zones in order to properly determine the amount of
land application with respect to the nutrient needs and vul-
nerability of P runoff. It then extracts the field attributes such
as the applicable field ID, hydrologic soil group, field slope
and spreadable area, etc., and calculates the P-Index. A good
example of the use of the P-Index Dialog Box is shown in the
P-Index worksheet for Alabama presented in Agronomy Tech-
nical Note AL-72 (USDA-NRCS, 2001). The P-Index worksheet
is a matrix with 11 field characteristics and five value factors.
Each field characteristic has a weighting factor that is mul-
tiplied by a value factor. The hydrologic soil group and field
slope (%) among 11 field characteristics were automatically
extracted from geodatabase of the PLDSS. The sum of these
values gives the P-Index result. The P-Index Dialog Box exam-
ines one field at a time, calculating the P-Index by the method
described above.
The P-Index calculation resulted in a value of 14 for the
selected field ID of 2281, with an area of 7.88ha and the P-
Index was Very low/Low (Fig. 5). The distance to calculate
the buffer zone was 25 ft recommended by buffer width for
property line.
3.2.2.2. Nutrient Needs Dialog Box. The Nutrient Needs Dialog
Box (Fig. 6(A)) allows the user to select a crop and then deter-
mine the amount of nutrient needed for each field based on
the results received from the P-Index Dialog Box. The execu-
tion of this module for nutrient needs resulted in 19.6 ton for
poultry litter type and 21.9 ton for compost type, respectively.
3.2.3. CNMP Application sub-module
Based on the results produced by running the Total Lit-
ter Produced and Total Nutrient Value Dialog Boxes (Farm
Operation sub-module) for the poultry farm selected andthe field selected by the P-Index and Nutrient Needs Dialog
Boxes (Fields sub-module), the CNMP Application sub-module
(Fig. 6(B and C)) enables the user to determine the land appli-
cation rate and calculates excess litter and compost.
The results of carrying out the CNMP Decision sub-
module for on-farm utilization were as follows: the amount of
land application showed 21.9 ton in compost. Consequently,
the excess litter and excess compost by the selected farm
were 712.5 and 67.7 ton, respectively. This means that the
Transportation Analysis module should be implemented to
optimize the transportation of the excess litterto a region with
a poor soil fertility problem, such as the Black Belt region of
the state.
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Fig. 3 The General Information Dialog Box showing the general information for the selected farm.
Fig. 4 The Total Litter Produced And Total Nutrient Value Dialog Boxes showing the total poultry litter produced from the
selected farm and the results that calculates its total nutrient value.
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Fig. 5 The P-Index Dialog Box showing the procedure that calculates the P-Index and determines the buffer zone from the
selected field and the results that calculates its P-Index.
Fig. 6 The Nutrient Needs Dialog Box (A) showing its results about calculating the nutrient needs for the selected field and
the CNMP application sub-modules showing their results about calculating the amount of land application (B) and excess
litter (C).
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Fig. 7 The result of the available area polygons within the 1.0 mile cut off and conceptual workflow for its modeling (A)
and the result of the origindestination matrix with a cut off value of 1.0 mile and default number of 10 to find destinations
(fields) and conceptual workflow for its modeling (B).
3.3. Transportation Analysis
For the CNMPs offsite utilization of excess litter, this module
suggests alternatives to the selected farm and field to make
it possible to determine the optimal transportation. Once
the user selects a farm, this module automatically carries out
the transportation analysis. Once a farm has been selected by
the CNMP module, unless the user changes the selection, the
information for that farm is used to create a link to obtain the
CNMP calculationresults.This module finds thebest routesfor
a given order of stops based on travel distance that is the least
costly path (distance cost) from a farm to fields. The Direc-
tions Window can also be displayed with turn-by-turn maps
that can be shown by clicking on the Show Map sub-module.
This modules applicability assessment was conducted by
making use of a randomly selected farm and carrying out
Fig. 8 The CNMP Assessment modules for on-farm (A) and offsite (B) application.
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Fig. 9 PLDBSS: (A) the data management sub-module for the CNMP data record form; (B) the CNMP data record form
exported to MS-Excel file format; and (C) the data search sub-module in the PLDBMS.
a transportation analysis within the county by running the
CNMP. The excess litter calculated by the CNMP Decision
module is then available for transport to the offsite, and theoutcome predicted. Fig. 7(A) shows the results based on cal-
culation of 0.3, 0.5, and 1.0 miles feasible area for the selected
farms, which can reveal how many land application locations
(fields) lie within each of these areas. This can also be used
to determine how best to relocate the least accessible farms
or place new ones to facilitate land application of the poultry
litter produced (Kang et al., 2006).
An OriginDestination (OD) cost matrix (Fig. 7(B)) is also
created to illustrate deliveries from the chicken houses to each
pasture. The results of this matrix can be used to identify the
land application areas that will be serviced by each chicken
house within a specific travel distance. Also, it determines
the total travel distance from each chicken house to its landapplication pastures.
3.4. CNMP Assessment Module
In order to perform an optimal poultry litter management
process, CNMP for on-farm utilization within the selected
county and transportation analysis for on-farm utilization in
the Black Belt region was conducted. The CNMP was applied
to all the fields from all the farms within Cullman County and
an OD matrix analysis was carried out for the excess litter.
Network analysis of the On-Farm Application and Offsite
Application sub-modules are similar to the Transportation
Analysis Module. These sub-modules enablethe user to deter-
mine the land application area and the ranking according to
travel distance from each of the farm to fields within a cer-
tain distance (1.0 mile for this example) (Fig. 8). This modulehelps theuser to selectthe optimal nutrient management plan
based on destination rank.
These sub-modules carried out optimal poultry litter man-
agement to transport the excess litter or compost from the
selected farm (chicken house) to the feasible area within
distance less than 1.0 mile for the On-Farm Application sub-
module and the Black Belt region for the Offsite Application
sub-module.
3.5. Implementation of the PLDBMS
The results of all previous modules are linked to the systems
database,named PLDBMS, which allows data storage, revision,and searches to be conducted through the Data Management
and Data Search sub-modules.
A summary worksheet (for record keeping) is generated
that contains general information, poultry litter informa-
tion, field information, land application, excess litter, etc.,
needed for the development of the CNMP on the selected
farm (Fig. 9(A)). This summary CNMP worksheet can then
be uploaded and exported as an Excel spreadsheet file
through the Data Management sub-module (Fig. 9(B)). Prior
to running each sub-module, the user can examine and
confirm the farm and field data that are used to calcu-
late the applied CNMP through the Data Search sub-module
(Fig. 9(C)).
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4. Conclusions
This study focused on the development and implementa-
tion of a GIS-integrated poultry litter decision support system
(PLDSS) for on- and off-farm applications of poultry lit-
ter in the Appalachian Plateau and Black Belt regions of
Alabama. Development of this DSS was initiated because offour main reasons. First, the poultry industry in Alabama
is mostly concentrated in the Appalachian Plateau region,
and improper distribution and over-application of litter for
more than 25 years in this region has resulted in buildup
of phosphorus in many pasture fields, which threatens
surface water quality. Second, currently available DSS for
land application of poultry litter do not support transporta-
tion analysis. Third, available DSS are difficult to use. And,
fourth, record keeping required by Alabama Department of
Environmental Management (to show compliance with reg-
ulations) is not supported by many of the currently available
DSSs.
Various modules provided in the PLDSS addressed many ofthese issues. For example, the CNMP module allows users to
develop a quick nutrient management plan and phosphorus-
Index, the transportation analysis module allows them to
minimize transportation cost, and the database manage-
ment module allows them to keep record of their activities.
We envision this system to be used by County Conserva-
tion District staff and/or the CAWVs in cooperation with the
County Conservation District staff. Once fully implemented,
the system will allow increased use of nutrient manage-
ment planning and P-Index, thus reducing over-application
of poultry litter. The transportation analysis will help dis-
tribute excess litter within the Appalachian Plateau region
or the Black Belt region. The transportation analysis willalso help minimize transportation cost. Thus proper use of
the PLDSS will help simultaneously minimize water qual-
ity impairment of water bodies and transportation cost,
thus providing optimal management of poultry litter in
Alabama.
The PLDSS will allow optimal land application and trans-
portation of litter first in the Appalachian Plateau region
and then transportation and land application in the Black
Belt region. This will ensure that the litter application pro-
tects the water quality in the Appalachian Plateau region,
minimizes transportation costs, and improves soil fertility
in the Black Belt region. Hence, this study will help alle-
viate water quality problems in the Appalachian Plateauregion and poor soil fertility problems in the Black Belt
region.
There are several benefits and implications of the PLDSS.
For example, if used for a long time, the PLDSS will supply
a detailed database of poultry litter applications. Using this
database, researchers will be able to study the hydrologic,
geomorphic, and ecological characteristics that control NPS
pollution in animal waste applied watershed. Further, this
database will provide a complete picture of theextent of poul-
try litter management problem in the Appalachian Plateau
region andthe accurate locationof thearea(within thisregion)
where poultry production is concentration. A company inter-
ested in developing value-added products from poultry litter
will then be able to identify hot spots of excess poultry litter.
Further, we will be able to accurately determine the potential
of expansion of poultry industry in the Appalachian Plateau
region.
As mentioned earlier, this system was designed for use
by County Conservation District staff and/or CAWVs, because
they have traditionally developed nutrient management plans
and P-Index for CAFOs and AFOs. Further, County Conserva-tion District staffs are trained in the use of ArcGIS system.
However, often County Conservation District staffs are unable
to assist all the poultry producers because of their concen-
tration in a few counties. The authors envision that to fully
optimize litter management (i.e., environmentally sustainable
application and proper distribution with minimum trans-
portation cost), in future, the litter management will need to
transferred directly in the hands of CAWVs, poultry produc-
ers, and farmers. With the increased useof web-based system,
a webGIS-based system with all the functionalities provided
in the PLDSS will be ideal. This will shift the task of proper
land application of litter and transportation of excess litter
in the hands of CAWVs, producers, and farmers. The trickwould be to develop this system in such a user-friendly man-
ner that a person with litter knowledge of computers is able to
use it.
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