AVGWLF and PRedICT softwares were used to estimate the Louisiana dairy industry's effect on water quality. Results indicated a 20 percent decrease in N and P but little decrease in sediment pollution even when best management practices were adopted in 75% of land.Livestock Production/Industries,

Gauthier, Wayne M.

Hall, Larry M.

Niu, Huizhen

Paudel, Krishna P.

Westra, John V.

English

Research Papers in Economics

 
Determination of BMP Adoption Effectiveness in the Louisiana Dairy  
               Production Region 
 
                                          
Larry M. Hall, Graduate Student 
Department of Agricultural Economics and Agribusiness 
Louisiana State University 
Baton Rouge, LA 70803 
lhall2@lsu.edu 
 
Krishna P. Paudel, Assistant Professor 
Department of Agricultural Economics and Agribusiness 
Louisiana State University 
Baton Rouge, LA 70803 
kpaudel@lsu.edu 
 
 
Wayne M. Gauthier, Associate Professor 
Department of Agricultural Economics and Agribusiness 
Louisiana State University 
Baton Rouge, LA 70803 
wgauthier@agctr.lsu.edu 
 
John V. Westra, Assistant Professor 
Department of Agricultural Economics and Agribusiness 
Louisiana State University 
Baton Rouge, LA 70803 
jwestra@agctr.lsu.edu 
 
Huizhen Niu, Instructor, GIS Lab 
Department of Agricultural Economics and Agribusiness 
Louisiana State University 
Baton Rouge, LA 70803 
hniu@agctr.lsu.edu 
 
Preliminary Draft, Do Not Quote 
 
Selected Paper prepared for presentation at the  
Southern Agricultural Economics Association Annual Meetings 
Orlando, Florida, February 5-8, 2006 
 
Copyright 2006 by Larry Hall, Krishna Paudel, Wayne Gauthier, John Westra, and 
Huizhen Niu. All rights are reserved. Readers may make verbatim copies of this 
document for non-commercial purposes by any means, provided that this copyright notice 
appears on all such copies. Determination of BMP Adoption Effectiveness in the Louisiana Dairy  
               Production Region 
 
 
Abstract 
 
AVGWLF and PRedICT softwares were used to estimate the Louisiana dairy industry’s 
effect on water quality. Results indicated a 20 percent decrease in N and P but little 
decrease in sediment pollution even when best management practices were adopted in 
75% of land. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Determination of BMP Adoption Effectiveness in the Louisiana Dairy  
               Production Region 
 
 
 
 Introduction   
 
     Dairy farms in Louisiana’s Florida Parishes can be considered to be both point and 
nonpoint sources of pollution. Five southeast Louisiana parishes (Washington, St. 
Tammany, Tangipahoa, St. Helena, Livingston) contribute over 90% of the dairy 
products for the state. However, these farms also constitute a large potential threat to the 
water quality of the area from dairy manure. Chemical compounds that may be necessary 
for plant growth on a farm may be harmful to nearby water quality. While phosphorus is 
required for plant growth it harms adjacent water quality if allowed to migrate into that 
water body. Since sediments, nutrients, pesticides and other contaminates may be washed 
from agricultural land, various Best Management Practices (BMPs) are designed to 
mitigate this threat to surface and groundwater (Appendix 1). BMPs are practical ways to 
ensure that these risks to the environment are reduced without hampering economic 
productivity. 
       BMPs are designed to reduce inputs is an important element of pollution prevention. 
The more a potentially harmful substance is used in agriculture, the more likely it is to 
negatively affect other parts of the environment. These reduction BMPs are tied most 
directly to fertilizers, manures and pesticides. Commonly recommended BMPs in the 
dairy production region of Louisiana are shown in Appendix 1. 
         The United States Department of Agriculture (USDA) recognized that agricultural 
chemicals and sediment from cropland could reduce the water quality of America’s surface and groundwater and instituted the Clean Water Act. While this act stipulates that 
individual states are responsible for controlling agricultural nonpoint pollution, the 
USDA installed both voluntary and mandatory policies to encourage farmers to adopt 
BMPs to address pollution issues.  
  Voluntary policies use an incentive to encourage the farm operator to adopt less 
polluting technologies and have been the primary approach used to reduce nonpoint 
source pollution. Two of the most common voluntary methods to encourage farmers to 
adopt less polluting practices are cost sharing and incentive payments. 
  Involuntary incentives force the farmer to use pollution-control methods through 
higher input costs or direct regulation. Taxes raise the price of an input to encourage less 
use and drive down pollution.  Another involuntary method to reduce pollution is 
regulations. Direct regulation is the most common involuntary method and requires farm 
operators to meet minimum design standards for certain pollution technologies or 
minimum performance standards for emission levels. 
The objectives of this paper are:  
 
i)  Given a suite of Best Management Practices (BMPs), which BMP combination    
               incur the least cost while still  meeting the required nutrient water standards in  
               dairy producing region of Louisiana. 
ii)  Evaluate three levels of pollution reduction scenarios and make 
recommendations for policy makers.    
 
Methodology        To accomplish the objectives of this study; an analysis is needed to determine if the 
BMP adoption resulted in significant improvement in water quality in the region. The use 
of  GIS-based software was crucial in this determination. The tool used was AVGWLF 
(Average Watershed Loading Function) developed to derive input for an “impaired” 
watershed and compare it to a nearby “reference” watershed through simulation. 
AVGWLF uses “layers” of information of accomplish this goal. Of course, the most 
important layer is the location of dairy farms. Additional layers are: weather, point 
sources of pollution, watersheds, basins, streams, unpaved roads, paved roads, county 
(parish) boundaries, septic systems, animal densities, soil types, and elevation data.  
      For our initial analysis, we choose a section of northern Tangipahoa Parish that 
included six subsection of the major watershed where a significant portion of dairy farms 
within the parish are located. These six subsections then formed a basin aggregate (Basin 
Aggregate 1). Our initial efforts for the study then focused on the layers of information 
within Basin Aggregate 1.   
     After the layers for Basin Aggregate 1 are entered, the AVGWLF application is used 
to create input data files for subsequent use in the Generalized Watershed Loading 
Function (GWLF).  This model simulates runoff, sediment, and nutrient (N and P) 
loadings from a watershed given the agricultural, forested, and developed land available. 
In addition, it contains algorithms to calculate septic system loads and point source 
discharge data. GWLF is a continuous simulation model that uses daily time steps for 
weather data and water balance estimations. Daily water balance is accumulated into 
monthly amounts and these calculations result in sediment and nutrient loads.         These estimates are then loaded into the Pollution Reduction Impact Comparison 
Tool (PRedICT). This model was developed for use in evaluating the implementation of 
agricultural and non-agricultural pollution reduction at the watershed level. The user can 
create scenarios for current versus future landscape conditions and pollution loads and 
predicts the reduction in pollution in the watershed on the different scenarios.  BMP 
implementation for pollution reduction is enacted at this point. The BMPs are group into 
eight categories: cover crops, conservation tillage, conservation plans, agricultural to 
forest conversion, agricultural to wetland conversion, nutrient management, grazing land 
management, a user defined BMP.  
 
 Data and Study Area 
     Data were collected from a survey sent to all 344 Louisiana dairy farms using a mail 
survey following the tailored designed method (Dillman, 2001). The survey contained 
four sections: Dairy Manure Disposal, the Dairy Termination Program (DTP) and the 
Milk Diversion Program (MDP) as policy instruments to reduce cow numbers so as to 
control the negative environmental impacts of cow manure, BMP adoption as measures 
to enhance the cow carrying capacity of the land without compromising the environment, 
and demographics.  
  Surveys were mailed first on May 2004 and then follow up surveys were mailed 
again after three weeks. After two weeks of mailing the survey, a reminder post card was 
mailed to each individual whom the survey questionnaires were mailed. In addition, 
telephone contact attempts were made to encourage responses. Only 49 surveys were 
received for a response rate of 14.24%. The low response rate reflects several aspects of current dairy production. The industry is in decline in Louisiana and some farmers on the 
mailing list were either out of business or had retired. In conversation with the farmers, 
many expressed a feeling that they were being constantly survey and were tired of the 
process. Several farmers felt that nothing good ever came out of such surveys because the 
price for their milk just keeps falling.  
     The survey determined BMP adoption among farmers through the use of thirteen 
adoption questions.  For example, waste treatment lagoons and cover and green manure 
crop participation rates were determined. If a BMP was not under current adoption, the 
farmer was asked to determine the level of total costs that he/she would pay to adopt. 
 
Results  
Figure 1. 
 
 
 
The first step in using AVGWLF is to add information “layers.” Figure 1 shows the 
location of dairy farms in Tangipahoa parish. Other layers include weather data, streams, unpaved roads, paved roads, point pollution sources, watersheds, animal density, soils, 
and elevation. 
Figure 2 
 
 
Six sub-watersheds are chosen that included a large number of the dairy farms. These six 
sub-watersheds are the aggregated into a Basin Aggregate (Basin 1) as shown in Figure 2. 
                                     
           Figure 3 shows the layers of data (nutrient, pesticides, transportation, and weather) 
that will be transferred to GWLF for further processing.     
 
Figure 4 
 
 
Figure 4 contains precipitation, evaporation, extraction, runoff, subsurface floe, point 
source flow, tile drain, and stream flow calculated by GWLF. 
 
Figure 5 
 
 
Figure 5 shows tons of erosion, sediment, dissolved nitrogen, total nitrogen, dissolved 
phosphorus and total phosphorus for a nine year period by month calculated using 
GWLF. Figure 6 
 
 
After the GWLF calculations, the data is input for use in PRedICT. Figure 6 shows cost 
information by BMP. PRedICT allows for BMP manipulations to estimate the effect of 
BMPs on pollutants in Aggregate Basin 1. 
 
The summary nutrient reduction results are as follows:     
                                                                           BMP Usage  
                                                         0%               25%                  50%             75%                                                         
       Total Sediment (lbs)        1,052,456        1,000,253         1,001,412       991,835 
       Total Nitrogen (lbs)            102,569             94,673              85,832         81,120 
       Total Phosphorus (lbs)         12,087             11,465               10,942        10,573 
 
           This study focused on three different future scenarios then compared an existing 
situation of zero BMPs with a 25%, 50% or 75% BMP implementation.  The total for 
BMPs #1 to BMP #5 cannot be greater than 100%. BMP #5 (agriculture to wetland 
conversion) can only be applied to lands with a slope greater than 3% and was limited to 
5% increase in the program. There were two major agricultural acre types: row crops and hay/pasture. Dairy production falls under hay/pasture and is not predicted by using BMP 
# 1 (cover crops) and BMP # 2 (conservation tillage).  
     Not all BMPs are expected to reduce pollution by the same amount. For example, 
BMP # 6 (nutrient management) reduces nitrogen by 70% and phosphorus by 28% but 
doesn’t affect sediment. BMP #7 (grazing land management) reduces nitrogen by 43%, 
phosphorus by 34% and sediment by 13%. 
     While Nitrogen and Phosphorus both deceased with increases in BMPs sediment 
didn’t actually increased slightly. Since BMP # 5 was limited to 5%, BMP # 6 was 
increased to 15%, which may have lead to the slight increase in sediment. However, all 
three variables decreased at the 75% level.  
 
Conclusions 
       Implementation of BMPs showed reduced pollution in three simulation scenarios for 
a small watershed basin in northern Tangipahoa Parish, Louisiana. Both nitrogen and 
phosphorus pollutants were reduced approximately 20% with a 75% increase in BMP 
usage. However, sediment pollution remained high even with the improved BMP 
implementation. While pollution reduction was achieved, cost increases significantly as 
the desired level of nutrient water quality increases (Table 1). Cost changes as the desired 
suite of BMP is modified from $ 642,238.5 to $1,621,389. The results show diminishing 
returns with BMP adoption. Therefore, policy makers funding for a 25% adoption would 
achieve almost half of the pollution reduction for approximately one-third of the cost of 
what would be achieved with a 75% adoption. Further study will include all five dairy 
producing parishes in Louisiana and their impact on regional water quality. References 
 
Dillman, D.A.  Mail and Internet Surveys: The Tailored Design Method, John Wiley and 
  Sons, Inc., New York, 2000. 
 
Evans, B, Lehning, D., Borisova, T, Corradini, K, Sheeder, S., Brown, W. 
  AVGWLF and PRedICT Manuals, Penn State Institute of the Environment 
  The Pennsylvania State University. 
 
Hilliard, C and Reedyk, S “Agricultural Best Management Practices” 
  Accessed from the web http://www.agr.gc.ca/pfra/water/agribtm_e.htm 
  on January 9, 2006 
 
Feather, P. and Cooper, J. “Voluntary Incentives for Reducing Agricultural  
  Nonpoint Source Water Pollution” Accessed from the web 
  Http://www.ers.usda.gov  on January 9, 2006 
F 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Table 1 
    Hay/Pasture      Sediment  Nitrogen  Phophorus 
BMP   BMP%  Acres  Cost/Acre 
Total 
Cost     (lbs)     (lbs)       (lbs) 
3  0  28076  30  0  1052456  102569  12087 
4  0  28076  30  0  1052456  102569  12087 
5  0  28076  170  0  1052456  102569  12087 
6  0  28076  7.5  0  1052456  102569  12087 
7  0  28076  220  0  1052456  102569  12087 
Total %  0   
Total 
Cost  0       
               
3  0.05  28076  30  42114  1008253  94673  11465 
4  0.05  28076  30  42114  1008253  94673  11465 
5  0.05  28076  170  238646  1008253  94673  11465 
6  0.05  28076  7.5  10528.5  1008253  94673  11465 
7  0.05  28076  220  308836  1008253  94673  11465 
Total %  25   
Total 
Cost  642238.5       
               
3  0.1  28076  30  84228  1001412  85832  10942 
4  0.1  28076  30  84228  1001412  85832  10942 
5  0.05  28076  170  238646  1001412  85832  10942 
6  0.15  28076  7.5  31585.5  1001412  85832  10942 
7  0.1  28076  220  617672  1001412  85832  10942 
Total %  50   
Total 
Cost  1056360       
               
3  0.17  28076  30  143187.6  991835  81120  10573 
4  0.18  28076  30  151610.4  991835  81120  10573 
5  0.05  28076  170  238646  991835  81120  10573 
6  0.18  28076  7.5  37902.6  991835  81120  10573 
7  0.17  28076  220  1050042  991835  81120  10573 
Total %  75   
Total 
Cost  1621389       
               
BMP 3   Conservation Plans (Crop Rotation/acre)       
BMP 4   Agricultural to Forest Conversion (Crop Residue Management/acre)   
BMP 5   Agricultural to Wetland Conversion (Terraces and Diversions/acre)   
BMP 6   Nutrient Management/acre         
BMP 7   Grazing Land Management/acre         
 
 
 
 
 
 
 
 
 Appendix 1 
 
Types of generic BMPs aggregated for use in the PRedICT system 
 
1)  Crop Residue Management 
2)  Vegetated Buffers 
3)  Crop Rotation 
4)  Cover Crops 
5)  Contour Farming/Stripcropping 
6)  Terraces and Diversions 
7)  Grazing Land Management 
8)  Streambank Protection 
9)  Nutrient Diversion 
 
 
 
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Agricultural Best Management Practices” Accessed from the web http://www.agr.gc.ca/pfra/water/agribtm_e.htm on

Mail and Internet Surveys: The Tailored Design Method,

Determination of BMP Adoption Effectiveness in the Louisiana Dairy Production Region.

Determination of BMP Adoption Effectiveness in the Louisiana Dairy Production Region.

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