Agronomy Research 18(3), 2004 2021, 2020
https://doi.org/10.15159/AR.20.180

A linear assignment based conceptual lifecycle assessment
method for selecting optimal agri-industrial materials
production pathway: A case study on Nigerian yam value chain
I. S. Dunmade
Mount Royal University, Faculty of Science & Technology, Department of Earth &
Environmental Sciences, 4825 Mount Royal Gate SW, Calgary AB T3E 6K6, Canada
*
Correspondence: idunmade@mtroyal.ca; israel_dunmade@yahoo.ca
Abstract. Lifecycle assessment is a robust tool for comprehensive environmental impact
assessment of products and processes. It provides users opportunities to identify the hotspots
along the lifecycle of a system and thereby enable them to implement improvement opportunities
as deemed appropriate. Production of agri-based industrial raw materials could be energy and
water intensive. Such endeavour could take a heavy toll on the environment in terms of resource
consumption and environmental pollution. The goal of this study was to develop an easy to use
and less data intensive conceptual LCA methodology for selecting optimal pathway along a
value-chain under two decision scenarios: the optimal techno-environmentally friendly pathway,
and optimal sustainability pathway. This proposed Linear Assignment Method integrated LCA is
a less data intensive conceptual LCA method that facilitates the selection of an optimal production
and processing pathway for agri-industrial materials, minimizes resource consumption and
reduction of potential climate change impact of agri-industrial materials value chain. The LCA
ISO 14040s aligned conceptual LCA method will be found useful in identifying potential hotspots
in a agri-industrial production process lifecycle, in selecting activity options that would result in
minimum ecological footprint, and help in removing obstacles in implementing a scoping
lifecycle analysis where cost, time and data availability are the impediments.
Key words: Africa, agri-industrial materials, ecological footprint, LAM (linear assignment
method), yam.

INTRODUCTION
Agri-industrial materials refer to agricultural produce used as feedstocks in the
textile, dairy, fashion, food, beverage and paper industry. It includes crops like cocoa,
coffee, tea, orange, sorghum, millet, cassava, yam, cocoyam, kenaf, sisal, and jute. Their
industrial applications include in the production of starch, biofuels, pharmaceuticals, and
other industrial chemicals. Decisions in this sector of the economy are often based on
profitability and regulatory compliance. The emerging trend in this sector is the
incorporation of corporate social responsibility and concept of sustainability.
Production of agri-based industrial raw materials could be energy and water
intensive. Such endeavour could take a heavy toll on the environment in terms of
resource consumption and environmental pollution. There is, therefore, a need to address
2004

environmental issues along with other social and economic factors. Lifecycle assessment
(LCA) is a robust tool for evaluating environmental-, social-, and social sustainability of
a product, a process or a system. Originally, LCA is utilized for comprehensive
environmental impact assessment of products and processes. It provides users with
opportunities to identify the hotspots along the lifecycle of a system and thereby enable
them to implement improvement opportunities as deemed appropriate. Lifecycle tool has
been used for evaluating environmental impacts of products and processes from
various sectors of our economy. Its use in agriculture includes using it to determine
Romero-Rey, 2020); livestock production systems (Ottosen, 2020),
and products from agro-based companies (Mfitumukiza et al., 2019; Farahani et al.,
2019). Although LCA is a comprehensive tool has been widely used in the agricultural
sector but its use is mostly in the developed countries. Its complexity and associated cost
has limited its utilization by agricultural stakeholders in the developing countries. The
goal of this study was to develop an easy to use and less data intensive conceptual LCA
methodology for selecting optimal pathway along a value-chain. This study proposed
the use of Linear Assignment Method based, less data intensive conceptual LCA method
that facilitates the selection of an optimal production and processing pathway for
agri-industrial materials, minimizes resource consumption and reduction of potential
climate change impact of agri-industrial materials value chain. The LCA ISO 14040s
aligned conceptual LCA method will be found useful in identifying potential hotspots in
an agri-industrial production process lifecycle, in selecting activity options that would
result in minimum ecological footprint, and help in removing obstacles in implementing
a scoping lifecycle analysis where cost, time and data availability are the impediments.
One of the contributions of this research is that this is the first time that Linear
Assignment Method (LAM) is integrated with the Lifecycle Assessment (LCA)
methodology to simplify the LCA process by eliminating the need for intensive data as
is the case with the traditional LCA (Fava and Cooper, 2004). There is no known
literature on the use of LAM integrated LCA approach. The use of the LAM integrated
LCA approach enables the stakeholders in the agri-industrial materials production value
scenarios: environmental friendly pathway or sustainability pathway.
Environmentally friendly pathway is the decision scenario that evaluates the value
chain to select the combination of technically sound processes with the lowest ecological
footprint. This pathway favors processes with the lowest resource consumption and
minimum emissions. The sustainability pathway goes beyond the environmental
sustainability to include the consideration of economic and sociocultural factors in the
process of designing/selecting the best pathway along the value chain.
This conceptual LCA methodology is particularly beneficial to agri-industrial
materials producers, processors and marketers in developing countries that may want to
carry out an LCA but cannot afford to purchase commercial LCA software necessary to
carry out the traditional LCA. It is also suitable for those that may not be able to handle
the complexity, data requirement and time commitment necessary for the conventional
LCA (Udo de Haes, 2004; Rebitzer & Hunkeler, 2006).

2005

MATERIALS AND METHODS
This proposed conceptual LCA method involved hybridization of linear assignment
decision method (LAM) with the ISO 14040s based LCA process in an easily
understandable and utilizable manner. The integration of LAM with the LCA process
was done at the lifecycle inventory stage of LCA. This proposed method is easy to
employ and it produces actionable results that would be found useful in decision-making
processes along agri-industrial materials value-chain.
Linear assignment method and reasons for its choice as a method to integrate
with LCA
Linear assignment method (LAM) is one of the multiple attribute decision making
(MADM) methods that utilize quantitative and qualitative data in facilitating the
f a small number of possible options.
In LAM, the choices are ranked based on their points of each criterion and are rank
ordered on the basis of their overall performance across the criteria. The evaluation of
the available choices often involve considering multiple conflicting attributes
(Abdolazimi et al., 2015; Azar, 2000). At each stage of agri-industrial material
production, a farmer/processor is often confronted with the need to choose among a
small number of options. Their choices at each stage often have to be based on a set of
weighted or unweighted criteria that may eventually have far reaching effect on
profitability, environmental impacts and socio-cultural consequences. So, their decisions
are of multiple attributes in nature.
Although there are many MADM methods, LAM was selected because it is
simpler/easier to understand and to use. In addition, it is technically sound and has been
used in many real-life situations requiring making choices from a small number of
options on the basis of a set of criteria. Examples of areas of applications of LAM were
in logistics (Liu & Wang, 2009); material selection (Jahan et al., 2010); optimum
maintenance strategy selection (Bashiri et al., 2011), and spare parts inventory
classification (Baykasoglu et al., 2016). Further literature on the theory and
applications of MADM and LAM specifically can be found in the works of Herrera &
Herrera-Viedma, 2000; Liu & Wang, 2007 and Chen, 2013.
The ISO 14040s based LCA process
Life-cycle assessment (LCA) is a robust tool for evaluating potential environmental
impacts of products, processes and systems. LCA enables the users to determine the
potential environmental impacts of their products or process even before they are
developed, thereby facilitating taking preventive measures rather than curative steps that
may be necessary after the facts. LCA also allows for consistent comparisons of
alternative system designs with respect to their environmental performance. LCA
consists of four major steps, namely: goal and scope definition, inventory analysis,
impact analysis, and LCA interpretation (Fig. 1) (ISO, 2006a and 2006b; Dunmade,
2013a and 2013b; Kazulis et al., 2018; Dunmade, 2019a).

2006

Figure 1. The four steps life cycle assessment process.

Conceptual LCA
The conceptual level of LCA, which is also referred to as scoping LCA or lifecycle
thinking, generally involves the use of generic secondary data and scoring of possible
alternative course of actions over a set of criteria. It is often used for selecting a more
promising option from among two or more available options. It is commonly used in
selecting conceptual product designs pending a more detailed analysis of the selected
option. It is useful when there are cost, time or data availability issues affecting carrying
out a more rigorous LCA. This level of LCA facilitates getting a rough idea/
identification of potential hotspots in a process, products, or system without the use of a
more rigorous level of LCA.
Goal and scope definition
ISO 14040s require that the goal of an LCA should articulate the intended
applications, reasons for implementing the LCA and the audience that will use the
information from the results. The scope definition set the boundary for the LCA study.
It specifies the function of the system, the functional unit, the data cut-off criteria.
Lifecycle inventory (LCI)

This second stage of the LCA
involves quantification and compilation
of data, usually in spreadsheet format.
This is the most time consuming step in
the LCA process. This is because the
needed data are either not kept or it is
not available in a usable form. Intended
users of LCA are usually discouraged/
frustrated
for
those
reasons.
Consequently, an effort to address this
problem would greatly enhance utilization

Figure 2. An illustration of LAM integrated
LCA process.

2007

of LCA for various purposes. This is where the use of LAM comes in handy because of
its simplicity and less data demanding. Fig. 2 is an illustration of LAM incorporated LCA.
It shows that LAM is integrated at the lifecycle inventory analysis stage of the LCA.
The incorporation of LAM to the LCA process
The integration of LAM into the life cycle inventory stage involves a professional
or manager evaluating each of the available options Aj,
for a production unit
process against a set of criteria S1
m that are essential for the successful
implementation of that unit process. The professional comparatively rate the options in
terms of how good they are on each of the criteria and compile the numerical score of
each option across all the criteria. He/she then rank order the options based on their total
scores. The option with the least total score across the criteria is the best option while
the option with the highest total score is the worst option for the unit process/opperation
of the value chaim. The professional or manager repeats the rank ordering and totaling
the score for each of the unit processes in the value chain. The rank ordering of the
options on the basis of their total score at the unit process/operational level enables the
decision maker to easily see the best and the worst options. Assemblage of all the
(operation level) best options is the optimal production pathway along the value chain
(Dunmade, 2013b; Dunmade & Anjola, 2019b).
Metrics of measurement
The aforemention rank ordering process starts with articulating the criteria by
which the various unit process options would be assessed and the metric for measuring
the performance of each process. The
Table 1. The six linguistic scale levels
framework allows the use of mixed
qualitative and quantitative metric or
Assigned
Linguistic rating
purely qualitative metric wherever
numerical value
The
best
1
necessary/relevant. The qualitative
Second
best
2
evaluation is done on the basis of a six
Third
best
3
ordinal linguistic scale that ranks
Fourth
best
4
available choices in order of their
Fifth best
5
goodness and assign numerical values
Sixth best (i.e. worst case) 6
according to the ranking. Generally,
in ordinal scales, it is the order of the
choices/values that is important and significant because the magnitude of the differences
between the choices may not really be known. Ordinal scales therefore provide good
information about the order of choices (Triola, 2007; MRK, 2020). Table 1 shows the
six ordinal linguistic scale levels and the numerical conversion of the linguistic ratings.
Decision analysis
Having determined the available options and articulating the basis for their
evaluation, it is necessary to determine the characteristics of the decision maker. This
methodology is premised on a single decision maker that is assumed to be rational and
wants to choose a unit process option that maximize his utility. Furthermore, it is also
assumed that in choosing the best out of the available options, he/she may set some
minimum limits/value on the performance of the options below which he will not be
ready to accept to choose any of the options.
2008

For a specific decision scenario, let Aj, j =
n be the identified unit process options
from which he/she wants to choose while Si, i = 1, 2, m are criteria/attributes on which the
options are to be evaluated. As a rational decision maker who intends to maximize his
utility, he/she will select the option with the lowest total score (Dunmade, 2004):
(1)
But if he/she has set some minimum performance limit for any acceptable option
on the sustainability factors, this limit can be written as
(2)
where is the required minimum performance for any acceptable option Aj on criterion Si.
Thus, he/she will choose process A* that both satisfy his/her minimum performance
requirements and maximize his/her utility. This can be written as
A*

(3)

Lifecycle impact analysis (LCIA)
This third step in LCA is the point at which the data collected and processed
regarding resource use and environmental releases at lifecycle inventory stage are
mapped/ modelled into environmental effects. This stage conventionally consists of three
mandatory steps of impact
category selection, classification
and characterization. The other
non-mandatory steps at this stage
in the LCA process are
normalization, grouping and
valuation. For this LAM integrated
conceptual LCA method, the
LCIA step involves trying,
compiling and diagrammatic
illustration of possible combinations
of operational options and
determining the outcomes. The
set of best choice (A*) from
Figure 3. An illustration of the optimal pathway
individual operations of the value
selection in LAM integrated LCA process.
chain (Fig. 3) constitute the optimal
pathway for the scenario under consdideration.
Lifecycle interpretation
This last step in the LCA process involves evaluating the LCI and LCIA data, and
determining environmentally significant issues from those data. Significant issues can
be identified by doing contribution analysis or anomaly assessment of the data. This
stage of LCA also involves evaluating the soundness of the decisions taken and validity
of assumptions made at each stage of the LCA process. Such evaluation ensures correct
interpretation of the results, and adequacy of conclusions and recommendations. It also
2009

improves confidence in the outcomes of the LCA study. Conclusion on the outcomes of
the study and recommendations for necessary actions are made after the evaluation. The
results of the LCA study may also be subjected to either internal or external peer/critical
review before the report is submitted to the client or published.
An illustration on the use of LAM integrated conceptual LCA method for the
selection of an optimal agri-industrial material production value chain/pathway
Agri-industrial material production system: yam as an example.
The process of producing and transforming a typical agricultural produce to a final
industrial material or products involve so many activities. Using yam as an example, the
production process involves land clearing, mound/ridge making, seed yams planting,
weeding, fertilizer and chemicals application, staking and harvesting (Hori & Oshima,
1986; Diop, 1998; IITA, 2013; Ike & Inoni, 2006; Maroya et al., 2014; Bassey, 2017;
Eze, 2018; FMAWRRD, 2020). And according to ANOL (2018), the postharvest
processing of yam into instant pounded yam flour, involves yam selection and weighing,
washing, peeling and slicing, parboiling, drying, milling, and packaging. Fig. 4 illustrates
the various processes involved in yam value chain resulting in multiple industrial
products obtainable from yam processing (Suzan & Gameiro, 2007; Sadh et al., 2018;
USOTA, 2020).

Figure 4. A network of main operational activities involved in yam production value chain
system boundary and its products.

Yam production process
Land clearing is the process of removing vegetation cover from a piece of land for
crop planting planting. It often involves removing trees, stumps, brush, stones and other
2010

obstacles from an area as required to increase the size of the crop producing land base
of an existing farm or to provide land for a new farm operation. Methods used to clear
land will vary depending on the type and density of native cover, prevailing regulations,
available technology, and affordability of modern methods. The choice of land clearing
method would in turn affect soil properties and agricultural produce yields. Umeghalu
& Ngini (2013) in their article on the effect of poor land clearing on soil and agricultural
produce highlighted five methods of land clearing operation. However the four
commonly used methods in Nigeria are:
1. Manual method involving the use of hand tools such as matchet, hoes, axes and
diggers for land clearing. It is a tedious method that leads to drudgery. Land cleared by
this method may be difficult to later work with machines as some stumps and roots may
be left in the soil.
2. Burning method involves setting the vegetation on fire. It is commonly used in
the savanna vegetation region of Nigeria. It is fast and not labor intensive. It however
can lead to decrease in the soil organic matter, nitrogen content, earthworm and
microbial population, as well as general fertility of the soil.
3. Chemical method utilizes arboricides to kill stumps and forest regrowth thereby
avoiding the utilization of the commonly used mechanical means of land clearing.
However some arboricides are highly poisonous and could have unexpected
consequences on humans and other organisms.
4. Mechanical method employs heavy machinery such as bulldozer and tractors to
clear vegetation. This method is adopted by large scale farmers. It is more costly than
the other three methods.
The rank ordering and scoring of the land clearing operational options is as shown
in Table 2 below.
Table 2. Land clearing options and their scores
Resource
Environmental
Option
consumption
pollution
Manual
1
1
Burning
2
2
Chemical
3
4
Mechanical
4
3

Efficiency of
operation
4
2
3
1

Total

Path ID

6
6
10
8

A1
A2
A3
A4

Mound/ridge making
This refers to the piling up of earthen materials either in rounded forms (mounds)
or continuous earthen elevation in a row or rows (ridges) above the plane. It is done in
preparation for seed yam planting to facilitate easy penetration of seed yam roots thereby
fostering its growth and eventual yield. There are three commonly used methods in
Nigeria, namely:
1. Manual method involving the use of hoes designed for the purpose. The use of
manual methods for mound /ridge making is generally plagued with drudgery and is only
suited for small scale farming.
2. Animal draught methods involve the use of animals such as donkey and bull to
which farm implements such as disk or mouldboard plough are attached, which draw
those implement to make ridges. This method is commonly utilized in Northern Nigeria.

2011

3. Mechanical method. This is similar to animal draught method except that
tractors are used instead of donkey or bull. This method is often used for large scale
farming.
The rank ordering and scoring of the mound/ridge making operational options is as
shown in Table 3 below.
The same rank ordering and scoring process was used for the rest unit processes in
the yam production value chain.
Table 3. Mound/ridge making options and their scores
Resource
Environmental
Option
consumption
pollution
Manual
1
1
Animal
2
1
Mechanical
3
2

Efficiency of
operation
3
2
1

Total

Path ID

5
5
6

B1
B2
B3

Seed planting
Yam seed planting and fertilizer application operations are often carried out
manually by small scale farmers while large scale farmers use mechanical methods
involving the use of planters and fertilizer applicators.
Staking involves the insertion/erection of long sticks in the soil near each sprouting
yam seed is used to train the yam vine to hang onto those stakes in order to facilitate
healthy growth. The staking operation involves cutting sticks of about 40 70 mm thick
and about 180 200 cm height, transporting them to the site, inserting each stick for one
or two growing yam vines, and training the vines to wind around the stakes. The staking
design could be in various patterns, namely: standalone, 4-across two rows, or stakes in
each row linked by horizontally lying top ones that are tied to the top of the standing
ones. To date it is only done manually. Transportation of the stakes may be manual,
animal drawn carriage or by a machine.
Weed control is often necessary at the early growth stage of the yam seedling
before the vines form a canopy. There are four commonly used weed control methods.
1. Manual method. This often involves the use of hoe and cutlass. This method is
often plagued with drudgery and suited for only small sized farms, just like other manual
farming operations.
2. Chemical method. This method involves the use of herbicides. It requires careful
handling as it may kill other things that were not the target of the application. It could be
done manually or mechanized.
3. Animal draught weeding method. This involves the attachment of weeding
implement to a set of farm animals such as donkey and bulls, and directing their
movement.
4. Mechanical weeding method. This involves the use of weeding tool mounted
farm machinery that may be self-propelled or manually driven. The weeding tool may
be cutters that farm machinery like mower or trimmers can be used. It may also involve
a tool that turns the soil on the weed.

2012

Pest control/chemical application
1. Chemical method. This common method involves the use of
pesticides/insecticides. It also requires careful handling as it may kill other things that
were not the target of the chemical application. It could be done manually or mechanized.
2. Biological method. This involves raising and releasing insects, birds or animals
that kill/feed on the pests.
3. Mechanical method. This usually involves the use of noise making devices that
scare away the pest. The most common one consists of string suspended metal gongs
that periodically hit each other as wind blows. The level of effectiveness of this method
is yet to be established.
Harvesting
There are two usable methods for yam harvesting.
1. Manual method. Majority of yam harvesting is done by using hoes or cutlass to
dig out the tuber from the soil. It usually involves cutting off the vine from the tuber,
removing the soil around the tuber, shaking the tuber and lifting it up from the soil.
2. Mechanical method. Tuber harvesting implement can also be attached to a
tractor that digs out the yams from the soil. This is suitable for mechanized large farms.
Storage
Losses in farm produce in many developing countries are largely due to lack of
appropriate storage facilities for storing harvested produce. This is often because small
holders can not afford the cost of modern storage facilities and these losses poses threat
to food security and constitute serious economic losses in many developing countries.
Yam is one of the farm produce that suffer from such losses (Amponsah et al., 2015).
There are two common methods of yam storage in Nigeria:
1. Traditional method. There are various versions of this method. One common
version involves tying yams unto erected stakes. The stakes are fenced to prevent human
theft and easy access by animals such as rodents that may want to feed on the yams. This
version allows cross circulation of air that elongates the lifespan of the tubers by
preventing decay and mold growth on the tubers.
2. Improved yam storage facility. In recent years, there are concerted efforts being
devoted to the design and development of modern yam storage facilities in Nigeria and
in Ghana (FAO, 1990; Amponsah et al., 2015 and Knoth, 2020). Improved storage
methods generally consist of ventilated buildings of various sizes with shelves on which
yams are stored. The storage facility may be naturally or artificially ventilated.
Yam post-harvest processing
Cleaning
The processing of yam to any industrial material or product requires the removal of
remaining soil that may still be clinging to it after harvesting it. A number of marketers
do put identification marks on their yams. The markings may be with paints, chalk or
charcoal. All these would need to be removed by washing before further processing.
There are two main methods of tuber washing which are also applicable to yam washing:
1. Traditional method involves hand washing each yam tuber in water usually with
a sponge. Like other operations involving the usual manual method, this method is
tedious and generally applicable to small scale processing.
2013

2. Mechanized methods could be either continuous or batch type. The most
common ones involve a motorized sieve-like cylinder rotating in a pool of water that is
fed with yams. The continuous version is often fitted with an auger or worm like device
that moves yams from feeding point to the output end.
Other yam processing operations to various industrial materials/products such as
slicing, crushing, frying, parboiling/cooking, drying, milling and packaging are
amenable to both traditional manual method and mechanized method depending on the
scale of operations as well as availability and affordability of the technology. Options
available for each operation are comparatively assessed in terms of their energy, material
and water consumption. Their environmental impacts are also comparatively evaluated
with regards to the extent to which they affect land degradation, water contamination,
air pollution and loss of biodiversity.
This example to illustrate this conceptual LCA method involves the use of the
method by a corporate organizati
from yam. The company has two farms under cultivation for the production of yams and
other crops. It also has a facility that process the yam into pando yam flour.
Limitations to the utilization of the method
The use of this method requires in-depth knowledge of operations required to
methods that could be used to accomplish a task/operation and his/her ability to correctly
evaluate and rank order them in terms of the various attributes developed to assess the
usable methods.
RESULTS AND DISCUSSION
Lifecycle inventory
Two decision scenarios were evaluated. The first scenario is that of that individual
that wants to choose the best environmentally friendly pathway along the value-chain.
The second scenario went beyond the consideration of just the technical and
environmental factors to include the economic and social factors (Zamagni et al., 2013).
1. Techno-environmental Scenario:
The LAM integrated LCA process starts with setting the goal and scope of the LCA
study using the ISO 14044 standard. Then comes the role of a decision maker that is
knowledgeable in: the operations constituting the value chain, available choices within
each operation, and the various characteristics of each choice in relation to the
environmental factors such as resource requirements and environmental releases. He/she
considers these factors and rank order the choices from the best to the worst. If there are
three available choices for an operation, the best choice in term of environmental
performance is assigned 1 while the worst choice is assigned 3. If there are six possible
choices, rank ordering them means the best choice is assigned 1 while the worst choice
is assigned 6. The decision maker goes through the rank ordering of available choices
for each operation till the last operation in the value chain. The set of choices that is
ranked 1 for each of the operations in the value chain constitute the optimal
environmentally friendly pathway along the value chain. Table 4 is an extract of
environmental focus analysis results where the goal of the conceptual LCA analysis is
2014

only to select a technically sound and environmental friendly optimal pathway for yam
production value chain.
Table 4. A sample results of technical effectiveness and environmental friendliness based analysis
Land clearing operation
Option
Res. cons. Env. pol.
Tech. eff.
Total
Path ID
Manual
1
1
4
6
A1
Burning
2
2
2
6
A2
Chemical
3
4
3
10
A3
Mechanical
4
3
1
8
A4
Mound/ridge making operation
Option
Res. cons. Env. pol.
Tech. eff.
Total
Path ID
Manual
1
1
3
5
B1
Animal
2
1
2
5
B2
Mechanical
3
2
1
6
B3
Seed planting
Option
Res. cons. Env. pol.
Tech. eff.
Total
Path ID
Manual
1
1
3
5
C1
Mechanical
3
2
1
6
C3
Fertilizer application
Option
Res. cons. Env. pol.
Tech. eff.
Total
Path ID
Manual
1
1
2
4
D1
Mechanical
2
2
1
5
D2
Staking
Option
Res. cons. Env. pol.
Tech. eff.
Total
Path ID
Manual
1
1
3
5
E1
Manual-animal
2
2
2
6
E2
Manual-mechanical
3
3
1
7
E3
Weed control
Option
Res. cons. Env. pol.
Tech. eff.
Total
Path ID
Manual
1
1
2
4
F1
Chemical
2
3
1
6
F2
Animal
2
2
3
7
F3
Mechanical
4
3
4
11
F4
Pest control
Option
Res. cons. Env. pol.
Tech. eff.
Total
Path ID
Chemical
2
3
1
6
G1
Biological
1
1
2
4
G2
Mechanical
3
2
3
8
G3
Harvesting
Option
Res. cons. Env. pol.
Tech. eff.
Total
Path ID
Manual
1
1
2
4
H1
Mechanical
2
2
1
5
H3
Storage
Option
Res. cons. Env. pol.
Tech. eff.
Total
Path ID
Traditional
1
1
2
4
I1
Improved
2
2
1
5
I2
Res. cons. resource consumption; Env. pol. environmental pollution; Tech. eff. technical effectiveness;
Econ. economic sustainability.

2015

2. Sustainability Scenario:
There are three main dimensions of sustainability: namely, environmental, social,
amd economic sustainability. Consequently, this scenario considers the three dimensions
in the selection of the optimal pathway. This is particularly important in view of the
ongoing trend in agri-industrial system analysis that necessitates going some steps
further to include potential economic and sociocultural/sociopolitical impacts of our
choices. Social factors consider various aspects of human well-being. The

methods are evaluated in terms of elimination/reduction of drudgery,
minimization of exposure to health risk, emotional trauma, and other possible
hazards that could affect human well-being (
. Looking at
the options available for each operation, the use of mechanical methods facilitate
the attainment of the aforementioned goals. This scenario follows the same process
as in the case of techno-environmental scenario. However, in addition to evaluating the
available choices for each operation on the basis of environmental factors, it also
consider social and economic factors (Roos, 2016). The choice that has the lowest total
of the combination of the environmental, social and economic factors is ranked first. The
choices are thus ordered from the lowest total to the highest total for each operation. The
set of choices that are ranked first over the value chain operations constitutes the optimal
pathway. Table 5 shows a sample results of sustainability based analysis that included
economic and social considerations along with the technical effectiveness and
environmental friendliness.
Table 5. A sample results of sustainability based analysis
Land clearing operation
Option
Res. cons.
Env. pol. Tech. eff. Econ.
Manual
1
1
4
4
Burning
2
2
2
1
Chemical
3
4
3
2
Mech
4
3
1
3
Mound/ridge making operation
Option
Res. cons.
Env. pol. Tech. eff. Econ.
Manual
1
1
3
3
Animal
2
1
2
1
Mech
3
2
1
2
Seed planting
Option
Res. cons.
Env. pol. Tech. eff. Econ.
Manual
1
1
3
2
Mech
3
2
1
1
Fertilizer application
Option
Res. cons.
Env. pol. Tech. eff. Econ.
Manual
1
1
2
2
Mech
2
2
1
1
Staking
Option
Res. cons.
Env. pol. Tech. eff. Econ.
Manual
1
1
3
3
Manual-animal 2
2
2
1
Manual-mech 3
3
1
2

2016

Social
4
2
2
1

Total
14
9
14
12

Path ID
A1
A2
A3
A4

Social
3
2
1

Total
11
8
9

Path ID
B1
B2
B3

Social
2
1

Total
9
8

Path ID
C1
C2

Social
2
1

Total
8
7

Path ID
D1
D2

Social
3
2
1

Total
11
9
10

Path ID
E1
E2
E3

Table 5 (continued)
Weed control
Option
Manual
Chemical
Animal
Mech
Pest control
Option
Chem
Biol
Mech
Harvesting
Option
Manual
Mech
Storage
Option
Tradi
Improv

Res. cons.
1
2
2
4

Env. pol.
1
3
2
3

Tech. eff.
2
1
3
4

Econ.
4
2
2
1

Social
4
3
2
1

Total
12
11
11
13

Path ID
F1
F2
F3
F4

Res. cons.
2
1
3

Env. pol.
3
1
2

Tech. eff.
1
2
3

Econ.
3
1
2

Social
3
2
1

Total
12
7
11

Path ID
G1
G2
G3

Res. cons.
1
2

Env. pol.
1
2

Tech. eff.
2
1

Econ.
2
1

Social
2
1

Total
8
7

Path ID
H1
H2

Res. cons.
1
2

Env. pol.
1
2

Tech. eff.
2
1

Econ.
2
1

Social
2
1

Total
8
7

Path ID
I1
I2

Res. cons. resource consumption; Env. pol. environmental pollution; Tech. eff. technical effectiveness;
Econ. economic sustainability.

Lifecycle impact analysis
An evaluation of the results shown in Tables 4 and 5 provides us some insights into
the best pathway for each of the two yam production value chain decision scenarios.
Fig. 5 shows the best yam production value chain pathway for the technoenvironmentally focussed decisions while Fig. 6 shows the best yam production value
chain pathway for an all encompassing sustainability based decision. It would be
observed that the environmentally friendly optimal pathway largely consist of manual
methods. The reason for this is because manual methods generally require less resource
to operate and they generate no or smaller emissions than other approaches.

Figure 5. An illustration of the best pathway for techno-environmental focused yam production
value chain.

2017

The sustainability optimal pathway (Fig. 6) mainly consist of mechanical
approaches. The main reason is because the use of mechanical methods generally protect
workers from drudgery and facilitates higher productivity. Thus, it is preferred to the
manual and other approaches. The combine effect of economic and social sustainability
balances the environmental sustainability for the attainment of all round sustainability.

Figure 6. An illustration of the best pathway for sustainability focused yam production value chain.

Systems Lifecycle Interpretation
Techno-environmental focused analysis results in Table 4 and Fig. 5 revealed an
emphasis on the use manual labour in majprity of the operaions along the yam production
value chain. The reason is not far fetched. Manual labour based operations minimizes
resource consumption and eliminates environmental releases that could lead to resource
depletion, loss of biodiversity, air polltion, water contamination and a number of other
environmental problems. However, business decisions would need to also consider
economic implications of its choices. Consequently, there is a need to include economic
and social factors in the analysis. A look at results of sustainability analysis results in
Table 5 and Fig. 6 showed that major emphasis is on the use of mechanized systems.
The reason being that mechanized systems facilitate mass production, reduced unit cost,
increased profit margin and drudgery elimination. A comparison of the environmental
results and sustainability results revealed only in pest control operation that both analysis
recommed the same approach, that is biological pest control.
Comparing both decision scenarios, sustainability based optimal pathway is more
comprehensive and it is a more balanced decision than environmentally optimal pathway
as it also consider social and economic factors. The only challenge is that the
sustainability decision scenario require someone with not only the indepth knowledge of
environmental characteristics of the system to implement the LCA process, it also
requires the decision maker to have the knowledge of the social and economic
characteristics of various choices available along the value chain.
CONCLUSIONS
This paper presented a simplified less data intensive linear assignment based
conceptual LCA method. The used of the LCA methodology was illustrated with a case
study yam production value chain. Contributions of this study includes its provision of
opportunity to choose the best pathway to produce agri-industrial materials in technically
2018

efficient and environmentally friendly manner. It also facilitates the use of lifecycle
concepts in selecting agri-industrial material production operations without going
through the rigour of data collection and related analytical issues. The methodology
would enable small to medium scale farmers and agri-processors in developing countries
to conduct an LCA of their products because many of the LCA software and databases
are beyond their affordability. In addition, this methodology is much easier to use than
the conventional lifecycle assessment method. Moreover, this LCA approach is less
costly and less time consuming than other known methods. The methodology can be
used by a manager, a policy maker or any professional to identify the best operational
pathway that is technically sound, environmental friendly, warrants economic
profitability and incorporate human welfare consideration. This methodology would be
found useful, not only for any agri-industrial material production value chain but also
for other production or service systems decision scenarios that require an evaluation of
environmental and socioeconomic consequeces of our choices.
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