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519

Chapter 16. Developing Software for Livestock Manure and

Nutrient Management in the USA

P.J. Hess

a

, B.C. Joern

a

, and J.A. Lory

b

a

Department of Agronomy, Purdue University, West Lafayette, IN, USA

b

Department of Agronomy, University of Missouri, Columbia, MO, USA

More and more crop and livestock producers will be required to develop nutri-

ent management plans to demonstrate to regulatory agencies that their operations

have sufficient crop acreage, seasonal land availability, manure storage capacity,

and application equipment to manage commercial fertilizers, animal manures, and

other land-applied nutrient resources in an environmentally responsible manner.

Computer software has been and will continue to be used to help develop these

plans. Previous software addressed some pieces of the management plan puzzle, but

were generally limited in scope and failed to address fully the temporal and spa-

tial nature of nutrient management or provide ways to accommodate multiple states

and changing regulatory reporting requirements. New nutrient management plan-

ning software needs to take these issues into account, utilize national databases and

standards, and take advantage of modern software technologies. This chapter dis-

cusses the limitations of previous planning software, the opportunities this presents

for new software, the data requirements of planning software, challenges and barriers

to creating this software, and a glimpse of what this new software might look like.

1 . INTRODUCTION

1.1 . US Livestock and Poultry Production

Livestock and poultry in the US excrete nearly 1.3 billion tons of fresh manure

annually ( Table 1 ). If this manure were placed in railcars, the resulting train would

circle the earth more than 3.5 times! The phosphate (P

2

O

5

) and potash (K

2

O)

excreted by these animals nearly equals annual US P

2

O

5

and K

2

O commercial fer-

tilizer consumption and the nitrogen (N) excreted exceeds 60% of US commercial

fertilizer N consumption. While more than half of the manure produced by cattle

in the US is excreted directly onto pasture and range lands, most of the manure

generated by pigs and poultry is collected and can be managed as a crop nutrient

resource. The “ collectable ” portion of livestock and poultry manure still constitutes

more than 50% of US commercial P

2

O

5

and K

2

O fertilizer consumption ( Table 1 ).

While the total N excreted in the collectable fraction of livestock and poultry

manure is nearly 35% of US commercial fertilizer N consumption, 30–85% of this

Nitrogen in the Environment: Sources, Problems, and Management

J.L. Hatfield and R.F. Follett (Eds)

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520 Nitrogen in the Environment

N may be lost to the atmosphere during manure storage and application depending

on the manure management system used by an operation. Additional N losses fol-

lowing application may also occur due to application timing, method and weather.

Therefore, the potential N value of collectable manure is likely less than 20% of US

commercial fertilizer N consumption.

Because of these N losses, when animal manure is applied to meet crop N

requirements, P

2

O

5

and K

2

O application rates can be 2.5–5 times crop uptake.

Consequently, fields that frequently receive livestock manure often have soil test P

and K levels that greatly exceed those needed for optimum crop production. In addi-

tion, the number of livestock and poultry farms in the US has decreased by approxi-

mately two-thirds in the last 30 years, while the number of animals in inventory has

increased ( USDA/NASS, 1999 ). This increase in animal density on livestock and

poultry farms can make it more difficult to find sufficient land near the operation to

utilize manure P and K effectively.

Table 1.

Estimated quantities of manure and nutrients produced annually in the United

States compared to commercial fertilizer consumption.

Manure

2

P

2

O

5

2

K

2

O

2

Animals

1

(millions)

(millions

of tons)

3

N

2

(thousands

of tons)

3

(thousands

of tons)

3

Beef cattle 65 773 4,284 2,057 3,049

Milk cattle 18 364 1,825 837 1,212

Hogs 61 94 777 496 407

Broilers 1,103 36 463 282 221

Turkeys 104 13 180 154 77

Layers 419 17 234 181 107

All animals 1,770 1,297 7,763 4,007 5,073

Collectable

manure

4

651 4,143 2,371 2,736

Fertilizer

consumption

5

11,897 4,424 5,178

1

Number of animals in inventory from 1997 Census of Agriculture ( USDA/NASS,

1999 ).

2

Excretion values adapted from Midwest Plan Service ( MWPS, 2000 ).

3

To convert to metric tons, multiply values by 0.907.

4

If assumes 100% of manure from beef cows and dairy replacement animals

(heifers and heifer calves) and 15% of manure from pigs, poultry, and other cattle is

not collected.

5

Average 1990–1999 US commercial fertilizer consumption ( AAPFCO-TFI, 1999 ).

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Developing Software for Livestock Manure and Nutrient Management in USA 521

1.2 . Policy Drivers

According to the US Environmental Protection Agency (USEPA) 1998 national

water quality inventory, nearly 40% of US waters surveyed are too polluted for

fishing or swimming. USEPA estimates that agricultural sources are responsible

for 60% of this pollution in rivers and streams and 45% of this pollution in lakes

( USEPA, 2000a ). In response to water quality impairments attributed to agricul-

tural sources, the US Department of Agriculture (USDA) and USEPA published

the Unified National Strategy for Animal Feeding Operations ( USDA and USEPA,

1999 ). This document emphasizes the need for livestock and poultry operations

to develop comprehensive nutrient management plans (CNMPs) to minimize the

impact of these operations on water quality and public health. The USDA Natural

Resources Conservation Service (NRCS) has published guidelines that define the

specific components of CNMPs ( USDA/NRCS, 2000 ). If all livestock and poul-

try operations are eventually required to develop CNMPs, over 300,000 plans will

be needed. The USEPA is developing specific regulations to address water quality

issues for large concentrated animal feeding operations via a permit nutrient man-

agement plan (PNP) ( USEPA, 2000b ). PNPs may be required for approximately

30,000 animal feeding operations. In addition, nutrient criteria are being developed

by USEPA for surface waters based on total N, total P, turbidity, and chlorophyll a

in the water column ( USEPA, 2000c ). Total Maximum Daily Loads (TMDLs) in

nutrient-impaired water bodies may be based on these nutrient criteria, which could

significantly increase the total number of nutrient management plans needed. To

satisfy both current and future regulatory reporting requirements, nutrient manage-

ment planning software that supports sophisticated add-in reports is needed since

both federal and state-specific reports may be required for the same operation. This

will require software that is national in scope.

1.3 . What Is a Livestock Nutrient Management Plan?

Nutrient management planning helps farmers develop strategies to use manure

and other fertilizers as nutrient sources for crop production in a manner that pro-

tects environmental quality. The planning process is documented in a written nutri-

ent management plan for possible review by regulatory personnel, consultants, or

agency personnel and for use by the farmer as a working plan. The plan includes

information about the operation ’ s animal types and numbers, the quantity of

manure produced, the manure nutrients available for land application, the storage

facilities where animal manure is collected and stored, the crop rotations and fer-

tilizer needs of crops where manure will be applied, the methods used for apply-

ing manure, and the timing of planned manure and other fertilizer applications. The

plan often accounts for manure produced over a multiple-year period. Local, state,

and national regulations can determine the specific information required in a plan.

At its simplest, a plan includes an estimate of the total quantity of manure and

nutrients produced by the operation during the plan period and shows how those

nutrients will be distributed (when, where, and how much) on the available crop

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522 Nitrogen in the Environment

land. A more comprehensive plan takes into account temporal, spatial, and environ-

mental limitations to show that the operation has sufficient crop acreage, seasonal

land availability, manure storage capacity, and application equipment to manage

manure and other nutrient resources in a responsible and sustainable manner.

1.4 . Strategic and Tactical Nutrient Management Planning

Strategic nutrient management planning uses long-term data and industry stand-

ards to help the farmer create a blueprint for handling manure and other nutrients.

These plans evaluate the sustainability of an operation ’ s approach to nutrient man-

agement over multiple years. Strategic plans determine if sufficient land is avail-

able for manure application, how often and how much manure typically needs to be

land-applied, and the typical fertilizer value of manure nutrients. These plans are

used by farmers as long-term planning tools and by regulatory agencies to insure that

proper measures are in place to collect and handle manure. A strategic plan identi-

fies the fields that will likely receive manure and the typical rates to be applied to

each field.

Tactical planning uses current data to solve immediate nutrient management

challenges. For example, tactical planning helps a farmer evaluate the impact of

above average rainfall on manure storage capacity and identify the best field to

apply manure under these wet conditions.

In some cases, the same data can be used both in strategic and tactical planning,

but the data will be collected or determined in different ways. Table 2 highlights

some of the differences in data used for strategic versus tactical planning.

2 . THE NEED FOR COMPUTER SOFTWARE

Most of the arithmetic involved in creating a plan is not difficult and can be

performed on a pocket calculator. However, the number of calculations required and

Table 2.

Differences in data used for strategic and tactical planning.

Strategic Planning Tactical Planning

30-year normals for weather Actual on-farm weather data or

data from nearest weather station

Most recent soil tests used for entire plan

period

Soil nitrate test levels

Yield goals and typical cropping sequences Actual yields and previous crops

Book value-based estimates or most recent

manure analyses used for entire plan period

Actual manure analyses and

measured volumes

Month or season of manure applications Actual dates of manure applications

Planned application methods Actual application methods

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Developing Software for Livestock Manure and Nutrient Management in USA 523

the repetitive nature of the calculations when many fields and manure applications

are involved can be daunting. Furthermore, the amount of reference material and

information about the operation that is needed at hand before the calculations can

be done is considerable. Added to this is the need to run various what-if scenarios

for making a non-sustainable operation sustainable or keeping an operation sustain-

able if it expands. Computer software has the potential to reduce the work of gener-

ating a plan, permit review of different nutrient management options, and generate

reports in a standard format. Use of approved computer software can be a form of

quality control, ensuring that the plan incorporates approved recommendations and

standards.

2.1 . Opportunities for New Nutrient Management Software

A survey of software programs that calculate dairy manure application rates

revealed that there were at least a dozen such programs available at the end of 1995

( Thompson et al., 1997 ). Many of these programs could supply several of the basic

components of a livestock manure management plan. Most were available from

the authors for a nominal fee and few had unusual hardware or software require-

ments. However, from the perspective of late 2000, these programs already sound

somewhat antiquated. In general, they can be characterized as pre-Windows ® , pre-

Internet, pre-geographic information system (GIS) programs.

Based on the survey ’ s descriptions, these programs suffered from many of

the same limitations. The following are areas where new software can bring novel

ideas and approaches to bear on the complex challenge of nutrient management

planning.

● Take advantage of Windows- and Web-based interfaces : Previous programs

used the limited text-only interface supported by operating systems such

as Microsoft ® MS-DOS ® that were in use at the time the programs were

designed. Today ’ s Windows- and Web-based software support the more pow-

erful and intuitive graphical interface expected by modern computer users.

● Fully address temporal issues : Earlier software focused on annual totals for

manure production and manure applied to each field. To meet water quality

goals, nutrient management planning must address the timing as well as the

amount of manure and other fertilizers applied to fields. Effective planning

must also help the farmer anticipate times of the year when there is a danger

of exceeding manure storage capacity.

● Enhanced management of spatial data : Previous software at most noted the

distance fields were from manure storage. In practice, nutrient management

planning requires evaluating the proximity of manure management practices

to many geographical features, including lakes, streams, wells, neighbors,

and steeply sloping land. Advances in the availability of GISs provide an

opportunity to integrate more sophisticated map-based features into nutrient

management software.

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524 Nitrogen in the Environment

● Process-oriented : Most of the earlier programs appeared to base manure N

availability and loss estimates on an annual or seasonal loss factor. Prediction

of N availability may be improved by process-oriented models that account

for the effects of time, weather, application method, and source characteristics

on transformations occurring in the field.

● Regional and national focus : Previous software was developed by individuals

who were focused primarily on the specific needs and conditions of a par-

ticular state. Nutrient management efforts are more similar than they are dif-

ferent from state to state. Supporting multiple states is not only cheaper in

the long run, but is consistent with the current trend of developing common

approaches for generating land application standards for multiple states. To

satisfy regulatory reporting requirements, software will be needed that supports

sophisticated reports. Both federal and state-specific reports may be required

for the same operation. This will require software that is national in scope.

● Designed to be extended or enhanced by users and third parties : Previous

programs were largely limited to enhancements supported by MS-DOS and

the DOS-based programming tools prevalent at the time the programs were

developed. Today ’ s users require ways to add value to software by incorpo-

rating ideas and innovations of their own. This gives users a personal stake in

what otherwise could be perceived as impersonal national software.

● Utilize existing standards for identifying and exchanging data : Data exchange

between earlier programs generally had to be worked out by the developers

themselves on a case-by-case basis. Today ’ s users may need more than one

nutrient management tool. If the tools adhere to standards and support com-

mon ways of identifying and exchanging data, the amount of data that must

be manually entered can be kept to a minimum.

● Take advantage of the Internet : Most software today can be updated by

downloading revisions or updates from the Internet. This requires a more

sophisticated way of packaging and installing the software. The Internet can

also be used to provide weather and geographic data relevant to nutrient man-

agement planning.

● Link to a GIS : Working with a GIS is now a common way of putting a friend-

lier, map-oriented interface on agricultural software.

● Provide both “ strategic ” and “ tactical ” approaches : A strategic approach

requires that the focus be on planning for the next several years; a tactical

approach must address immediate and short-term planning and recordkeep-

ing needs; and a bimodal approach requires a way to switch cleanly between

modes.

3 . DATA REQUIREMENTS AND ACQUISITION

Easy access to relevant data is the foundation of successful computerized

nutrient management planning. Automated data acquisition is one of the primary

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Developing Software for Livestock Manure and Nutrient Management in USA 525

potential benefits that new software can have on nutrient management planning.

Automated data acquisition can reduce much of the drudgery of manual data input,

provide more accurate and timely information, and include more of the information

needed for developing detailed plans.

Transfer of data between programs is not assured; substantial effort must be

applied to standardize data among programs and develop protocols for communica-

tion between them. For example, the apparently simple task of importing soil test

results from different soil testing laboratories into planning software is only now

being resolved.

3.1 . External and Operation-Specific Data

Data required by planning software consist of two types, external and operation-

specific. External data typically are derived from state and national databases. These

data can be modified, but only infrequently. Operation-specific data are unique to the

operation and often vary from year to year. Strategic planning relies heavily on exter-

nal, non-temporal data, while tactical planning demands operation-specific, temporal

data. Strategic planning requires generalization, while tactical planning forces better

data collection. The more recent the data, the better the tactical plan will be.

Examples of external data include:

● Location data, including state, county and watershed boundaries.

● Soil survey attributes.

● Long-term weather data.

● Fertilizer recommendations.

● Plant nutrient removal rates.

● Typical manure excretion volume and nutrient content.

● Soil test response to nutrient inputs.

● Nutrient availability calculations.

● Digitized orthophoto quadrangles (DOQs).

Examples of operation-specific data include:

● Field layout, including predominant soil type, total area, spreadable area, set-

backs, buffers, and distance from manure storage.

● Soil test levels.

● Current weather data.

● Crop rotation and yield goals.

● Manure storage facilities.

● Animal numbers, types and rations.

● Manure volume and analysis.

● Equipment types and specifications.

● Fertilizer and manure applications.

● Planting, residue, tillage and harvest information.

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526 Nitrogen in the Environment

3.2 . Standards for Identifying Data

Two obstacles prevent data from one program from being used in another pro-

gram. The first is the way in which the information is encoded and stored. For

example, are the data in a computer file or a paper report? If the data are in a com-

puter file, what is the file ’ s format? Is it a spreadsheet file, a text file, or some other

type of file? Software that imports data must be able to identify and understand the

file ’ s format to read the file. Overcoming data format barriers is largely a technical

issue and can generally be solved through the development of conversion tools or

program support.

The second obstacle is the problem of identifying and describing data. A pro-

gram that imports data must be able to identify each piece of incoming data. With

agricultural data, there are a number of areas where standards for describing data

would be useful. In some cases, standards have recently emerged or are being devel-

oped. In other cases, no standards yet exist.

3.2.1 . Farm field identification

Unlike street addresses for houses and businesses, farm fields are fairly amor-

phous, dividing and combining as they are sold, rented, farmed, and managed from

year to year. Producers may have more than one way of identifying fields. For

example, they might have one system based on field ownership. This could corre-

spond to the traditional USDA Farm Service Agency (FSA) farm/tract/field system

of field identification. They might have another system based on how the field is

managed, in which a field is divided into subfields based on soil type, drainage,

proximity to water, or other factors. Each subfield might be managed differently for

manure even though the entire field is planted and harvested the same. A field could

also be identified by the latitude and longitude of points on its boundary, although

this is less a method of identification than a method of locating the field and is most

useful within the context of a GIS.

3.2.2 . Soil test data identification

With soil test data, the problem of identification is twofold. Not only does the

field from which the sample was taken need to be identified, but the particular test

and units used by the laboratory where the sample was processed must also be

known. With a sample ’ s field identification, the field ID must travel with the sample ’ s

data so it appears alongside the test results in the report or data file returned by the

laboratory.

Programs that import soil test results must also know, for example, which value

is pH and which is P. Furthermore, the program will need information about the

kind of data being provided. For example, the method used to measure soil test

P (e.g. Bray P-l, Mehlich III, Olsen, etc.) and the units (e.g. parts per million or

pounds per acre) must be known to properly interpret the incoming data.

Data standards can be used to facilitate transfer of information between pro-

grams. These standards can be program specific, in which a program has certain

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Hatfield J.L., Gandini A. (eds.) Nitrogen in the Environment

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