1
LUCTOR: introduction and exercises
H. Hengsdijk
1.
Introduction
This document is a brief introduction to LUCTOR 4.0 (Land Use Crop Technical
coefficient generatOR). LUCTOR generates technical coefficients for cropping systems in the
northern Atlantic Zone of Costa Rica (Hengsdijk et al., 1998). A cropping system can be
characterized by its so-called ‘definition criteria’ that explicitly defines the environment and
management options.
Technical Coefficients are inputs and outputs of cropping systems expressed per hectare
(Hengsdijk et al., 1996). Examples of technical coefficients are costs of production, yields in
different quality classes, sustainability and environmental indicators such as soil nutrient
balance and biocide use, and labor use. Technical coefficients are used in linear optimization
modeling to select combinations of land use activities that maximize a certain goal under
specified boundary conditions (restrictions). Often, the goal (objective function) is value
added (‘profit’), while restrictions can be related to the amount of resources available (land,
labor), marketable volumes of products or some environmental limitations (such as allowable
biocide use). Linear programming models of such type are often used in exploratory land use
studies (Rabbinge & Latesteijn, 1992; WRR, 1992; Veeneklaas et al., 1994; Bakker et al.,
1998). In Costa Rica, land use analysis methodologies using Linear Programming techniques
have been developed at settlement and district level for the Atlantic Zone (Schipper et al.,
1995; Stoorvogel, 1995; Schipper, 1996; Jansen et al., 1997a; Bouman et al., 1999d). Here,
the approach to linear programming and its use in exploratory land use studies is not further
explained. Merely suffice to say that LUCTOR is a tool that generates technical coefficients
for a large number of cropping systems. Equivalent tools exist for the generation of technical
coefficients of animal, pasture and animal feed acquisition systems (Bouman et al., 1998a). A
linear model can select the optimum combination of cropping, animal, pasture and feed
acquisition systems by maximizing explicitly defined objectives.
LUCTOR is developed for cropping systems in the northern Atlantic Zone of Costa Rica.
However, the model is set up in a generic manner so that by adapting the input files, users can
make LUCTOR relatively easy suitable to other environments. Technical coefficients for
beans, cassava, rice, maize-grain, maize-fresh cobs, pineapple-local market, pineapple-export
market, banana, plantain, palmheart, melina, teak and natural forest can be generated.
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In the following three sections, a brief explanation is given on some important concepts
used, the structure of LUCTOR and the definition criteria used to characterize cropping
systems. In section 5 some exercises are described to familiarize users with concepts and
results of LUCTOR.
2.
Concepts
LUCTOR generates technical coefficients for actual as well alternative cropping systems.
The former represent current production systems in the region while the latter are technically
feasible cropping systems that are possibly not yet widely practiced in the region. In general,
actual cropping systems have negative nutrient balances (indicating soil nutrient depletion)
resulting in a lower production potential in future years. In contrast to alternative systems that
are aimed at maintaining soil nutrient stocks (i.e. nutrient balance is zero) using the so-called
‘target-oriented approach’ that has been developed during a number of explorative land use
studies by AB-DLO and TPE-WAU in Wageningen, The Netherlands (Van Ittersum &
Rabbinge, 1997). The ‘target oriented’ approach implies that an optimal combination of
inputs is identified to realize a particular target yield defined by the user. In case of nutrients
LUCTOR calculates the amount of fertilizers required to replenish withdrawn and lost
nutrients. Inputs are calculated on the basis of systems-analytical knowledge on input-output
relations for the cropping system under consideration. Target production levels may vary
from potential production levels to very low levels. In the first case, high external input levels
(e.g. fertilizers, biocides) will be required, and in the second case, low external input levels
will be simulated. Next to desired production levels, the manner of production (technology)
can be specified. For instance, certain operations may be performed with machinery or may
alternatively be done manually (or using a combination method).
By specifying a number of target production levels, the environment and a number of
different technologies that may be used (the definition criteria of a cropping system),
LUCTOR ‘generates’ various technical coefficients that characterize cropping systems.
‘Classical’ input coefficients are the use of resources such as fertilizers, biocides, machines,
labor, and - of course - the total costs of production. ‘Classical’ output coefficients are yields
and the economic value of the yield. Next to these ‘classical’ coefficients, Technical
Coefficient Generators also calculate a number of other parameters that are associated with
the modeled cropping systems. These technical coefficients are called ‘sustainability
indicators’ or ‘environmental indicators’, and quantify effects to the environment. Examples
are losses of nutrients and emissions of biocides to the environment that are associated with
each cropping system. These technical coefficients can be used in linear programming models
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to set restrictions on the selection of cropping systems based on environmental or
sustainability issues.
3.
Structure of LUCTOR
LUCTOR version 1.0 was developed in EXCEL 5.0 but the newer version 4.0 operates
under Microsoft Office 97. To operate it only basic knowledge of the spreadsheet program is
required. The user only needs to fill in the definition criteria, which characterize the cropping
system using custom-made dialog boxes. The definition criteria are the driving variables for
the calculation of technical coefficients for each cropping system. They determine for which
environment, production level and management options technical coefficients are calculated
and hence which data, parameters and calculation rules are applied.
The structure of LUCTOR is modular; i.e. data and calculations are in separate files. Each
parameter or calculation rule is described in the files so that they are self-explanatory and
transparent. To generate technical coefficients a set of files for each type of cropping system
is required. They can be divided into files (i) with data and basic parameters, (ii) with
calculation rules and (iii) files with generated results. One file contains Visual Basic programs
that are required for the dialogue boxes and to automate procedures that return frequently.
The user of LUCTOR will not face these programs, since they are hidden. In Annex I an
overview is given of all LUCTOR files, their content and what files are used for which
cropping systems.
4.
Definition criteria of cropping systems
In Table 4.1 the definition criteria and their options for each criterion are shown for
annual, pineapple and perennial cropping systems. For timber cropping systems only three
definition criteria apply (type of activity, soil type and crop type). These will not be further
discussed in these exercises. Combining an option of each definition criteria results in unique
cropping system. Theoretically all options can be combined in any combination. However,
not all combinations are feasible due to ‘technical’ constraints, e.g. soils can be unsuitable to
grow certain crops, the low biocide option is considered infeasible for bananas due to high
infestation pressure of Sigatoka, etc. These factors are accounted for in LUCTOR. In case
only unfeasible options are selected LUCTOR will respond with a message indicating so.
Alternative cropping systems (see section 2) are defined in such a way that the annually
withdrawn nutrients from the system due to removal of marketable products and inevitable
losses (leaching, denitrification and volatilization) are replenished by nutrients in the annual
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supply from natural resources (deposition and nutrient fixing micro-organisms) and in
fertilizers. For actual activities LUCTOR calculates balances of nutrient in the soil
(depletion/surplus) based on (possible) fertilizers applications and realized production levels.
The ten target yield levels only refer to alternative cropping systems. The maximum
attainable target yield is based on expert knowledge and is stepwise reduced resulting in ten
yield levels of which the minimum level is 10% of the maximum. The production level of
actual cropping systems is based on regional averages.
Soil characteristics determine which soils are suitable to grow a crop, maximum attainable
yield level and nutrient recoveries. Some crop/soil combinations are only feasible after
construction of a drainage which costs are taken into account.
Table 4.1
Definition criteria and the distinguished options per criterion for cropping
systems.
Definition criterion
Options
1. type of activity
2 (actual and alternative)
2. target yield level
11 (10 target yield levels for alternative activities, 1 yield level for actual
activities)
3. crop type
13 (bean, cassava, rice, maize-grain, maize-fresh cobs, pineapple-local, pineappleexport, banana, palmheart, plantain, teak, melina and natural forest)
4. soil type
3 (fertile poorly drained, fertile well drained, infertile well drained)
5. mechanization level
2 (low and high mechanization level)
6 crop residue strategy
2 (harvesting and left in the field)
7. herbicide level
2 (low and high herbicide level)
8. biocide level
2 (low and high biocide level)
9. cycle length
2 (one or two years, only applicable for pineapple)
Two types of pineapple crops are available, one for the export market and one for the local
market. Both differ e.g. in the used variety, planting density and length of the crop cycle but
more important is their difference in post harvesting handling. Pineapple for export is preprocessed at the farm of which the inputs (capital and labor) are taken into account in the
technical coefficients. For maize also two types have been defined, one for grain production
and one for production of fresh cobs. Both have a different economic value and since fresh
cobs are harvested in an earlier stage than grain maize both differ in nutrient dynamics.
Next to the type of activity, yield level, soil type and crop type the user has to specify the
type of management, i.e. level of mechanization, level of herbicide and level of other
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biocides. For each of these definition criteria two extreme levels are defined, a low and a high
level.
Mechanization is due to high rainfall intensities combined with compaction characteristics
of soils in the northern Atlantic Zone and crop characteristics (narrow passage in perennials)
limited to mainly soil preparation operations. It is assumed that the high mechanization level
(with mechanized soil preparation) results in a yield increase due to improved soil conditions
compared to a manual soil preparation.
Crop protection agents are divided into herbicides and biocides. The latter include
insecticides, fungicides and nematicides. In the low herbicide option herbicides are
substituted by manual weeding which requires more labor but reduces the use of active
ingredients. Manual and chemical weeding are supposed to be completely substitutable, thus
not affecting the yield level. In the low biocide variant chemical insecticides and fungicides
are reduced with 50% compared to the high biocide variant. It is assumed that with better crop
hygienic measures, - requiring extra labor -, the use of fungicides and insecticides can be
reduced. However, it is assumed that some yield losses are inevitable compared to the high
biocide variant in the disease and plague susceptible (humid) environment of the northern
Atlantic Zone.
The technical coefficients of cropping systems include:

Production (of different quality classes, if applicable)

Labor requirements

Costs of production

Environmental and sustainability indicators

Fertilizer use specifications (N, P and K)

Equipment requirements
See Annex II for a specified list of all technical coefficients, their codes and units.
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5.
Exercises
Exercises in this section are a brief introduction to the functioning of the Technical
Coefficient Generator LUCTOR with the aim to familiarize users with concepts and the type
of results. Four exercises with LUCTOR will be made: one to generate technical coefficients
of actual and alternative cropping systems, one to generate technical coefficients of a crop
with different management options, one to generate technical coefficients of different crops,
and one in which the effect of different parameter values are analyzed.
Moreover, the user will be acquainted with dialogue boxes that are used to define the
criteria options of land use systems and other automation procedures that facilitate the
generation of technical coefficients.
5.1
Starting LUCTOR
Install LUCTOR according to the description given in Annex IV. After having installed
LUCTOR the exercises can be started.
 To start EXCEL click on the Excel program icon in your Microsoft Toolbar or Initial start
up.
 Go to the directory with the LUCTOR files. Note all files that are presented in Annex I.
 Open the file LIST.XLS. Subsequently, press [Ctrl+t] to activate a dialogue box with user
options. Seven options are available:
(i) Generate TCs for annual cropping systems,
(ii) Generate TCs for pineapple cropping systems,
(iii) Generate TCs for perennial cropping systems,
(iv) Generate TCs for timber cropping systems
(v) Return to active worksheet,
(vi) Combine XLS-output files, and
(vii) Close all files.
Choose the first option (i) ‘Annual cropping systems’ by clicking the option with your
mouse. When the option is highlighted click with your mouse the button [Just do it!] in the
right corner.
 All files required to generate technical coefficients for annual crops (beans, cassava, rice,
maize-grain, and maize-fresh cobs) will now be opened. Wait till all files are open. The
active file will be the output file ANN_IO.XLS. View the other files by pressing [Alt+W]
or clicking Window in the menu bar. Compare the opened files with the file list shown in
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Annex I for annual crops. Notice that some files contain more than one worksheet with
data or calculations.
 Study briefly the content of each opened file. At the top of each worksheet is a short
description of its content. The user can switch to another file by pressing [Alt+W] and
clicking a filename in the file list.
After having performed these instructions the user can start with the first exercise.
5.2 Exercise 1: Differences between actual and alternative cropping systems.
This exercise will show the user differences between actual and alternative cropping
systems. In actual systems soil nutrient balances are calculated as function of current attained
yields, current fertilizer gifts (if applicable), soil properties, and natural inputs of natural
resources. This may result in depletion or accumulation of nutrients in the soil. In contrast to
alternative systems which are aimed at equilibrium nutrient balances. The soil nutrient
balance is an important indicator of sustainability since a depletion of nutrients will result in a
future reduction in production potential. The ‘price’ to pay for sustainable cropping systems
(alternative cropping systems) is a high input (costs) of fertilizers. The land use systems that
will be generated help to analyze the sustainability of cropping systems.
In this first exercise the user is acquainted with the use of dialogue boxes with definition
criteria that will be used throughout the course to define options. The user only has to turn on
check boxes by clicking with the mouse.
Maize-grain is taken as a first example. To facilitate comparison, actual and alternative
cropping systems will be generated with similar management options.
 Press [Ctrl+s] to activate dialogue boxes with the definition criteria and their options. The
first dialogue box asks the user to define the type of activity. Two options, each with a
check box are available: actual and alternative. The user must select those criteria options
for which technical coefficients must be generated. This is done by turning on/off the
check boxes. Click with the mouse on the option or check box in front (both will work) to
turn it on. When the option is clicked once again the check box will be turned off. In this
exercise we will examine differences between actual and alternative cropping systems.
Therefore, both check boxes should be turned on by clicking on the check boxes.
Subsequently, click [Next]. It is noted here that this selection procedure can be stopped
any time with clicking the [Exit] button or can be reversed by clicking the [Back] button.
This may happen, e.g. when an incorrect check box is turned on or off while already
having pressed the [Next] key.
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 The dialogue box of the following definition criteria appears automatically, the target
yield level of activities. Only turn on the check box for 100% target yield and click
[Next].
 The dialogue box of the crop type appears. Since in this exercise maize-grain systems will
be compared turn on the check box for maize-grain and click [Next].
 The dialogue box of the soil types appears. Turn on the check box for Soil Fertile Well
drained and click [Next]
 The dialogue box for the mechanization level appears. Turn on the check box for low
mechanized level and click [Next].
 The dialogue box for the crop residue strategy appears. Turn on the check box for crop
residues left in the field and click [Next].
 The dialogue box for the herbicide level appears. Turn on the check box for the high
herbicide level and click [Next].
 The dialogue box for the biocide level appears. Turn on the check box for the high
biocide level and click [Next].
LUCTOR will now automatically start to calculate the technical coefficients for the
selected options. When finished the file ANN_IO.XLS will be the active worksheet
containing the technical coefficients. The first 9 columns contain codes of the generated
activities. In column 10 the codes are shown of the generated cropping systems. The first
three letters of the code indicate the soil type, the following two the crop type and the last part
contains the type of activity plus target yield level (letter plus number), biocide level (second
letter), herbicide level (third letter) and mechanization level (fourth letter). The ‘H’ stands for
a high level and ‘L’ for a low level. The code ends with the length of cropping cycle in years.
See for a complete overview of the codes Annex III. In columns 11 and 12 additional codes
are given that are of no relevance for the exercises (see also Hengsdijk et al., 1998). The
generated technical coefficients can be found to the right of these codes. The headers explain
the content of these columns. See Annex II for a complete overview of heading-codes,
description and units.
 Fill in Table 5.1 the relevant technical coefficients for both maize systems.
 After having filled in the technical coefficients for maize in Table 5.1 we will repeat the
exercise for cassava. Press [Ctrl +s] to pop up the same dialogue boxes as before.
LUCTOR will automatically delete the technical coefficients of both maize systems.
Proceed as described above. Change only the dialogue box for the crop option: turn the
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check box for maize-grain off and turn the check box for cassava on. When entered the
last dialogue box (biocide level) LUCTOR calculates the new technical coefficients for
cassava and write them to the output file ANN_IO.XLS. Fill in Table 5.1.
Table 5.1. Yield export quality product (EXP in kg/ha/yr), labor required (CLABA in d/ha/mth),
costs (CCOST in colon/ha/yr), Nitrogen balance (NBAL in kg N/ha/yr), and N-gifts (FIN in kg
N/ha/yr) of simulated actual and alternative cropping systems.
Cropping system code:
EXP
CLABA
CCOST
NBAL
FIN
Maize:
SFW.ZM.F0HHHL.01
SFW.ZM.F9HHHL.01
Cassava:
SFW.ME.F0HHHL.01
SFW.ME.F9HHHL.01
 Study the results obtained from actual and alternative cropping systems of maize and
cassava. Note the equilibrium N-balance of both alternative systems and corresponding
high N-requirements.
5.3 Exercise 2: different management options
In this exercise the effect of different management options on technical coefficients is
examined, i.e. different herbicide, biocide and mechanization options. Substitution of some
production factors is possible without affecting yield levels, such as chemical herbicides that
can be replaced by manual weeding. Other production factors are less substitutable without a
reduction in yield, e.g. biocides. Integrated pest management (IPM) methods may reduce the
use of biocides if a yield reduction is acceptable. In practice this implies that lower emissions
of biocides to the environment attained with IPM are accompanied with lower yields. From a
viewpoint of optimal resource allocation such trade offs have to be taken into account in
linear programming models. Disregarding such possibilities would block prospects for
agricultural development in more ‘environmentally friendly’ directions.
As an example we will generate different management options for alternative maize-grain
systems.
 Start from where you finished exercise 1.
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 Press [Ctrl+s] to activate the dialogue boxes with the definition criteria and their options.
The first dialogue box asks the user to define the type of activity. Only turn on the check
box for alternative activities and turn off the check box for actual activities. Click [Next].
 Turn on the check box for 100% of the target yield and click [Next].
 Turn off the check box for cassava and turn on the check box for maize-grain. Click
[Next]
 Turn on the check box for Soil Fertile Well drained. Click [Next]
 Turn on the both check boxes for the low and high mechanization level. Click [Next]
 Turn on the check box for ‘Crop residues left on the field’. Click [Next]
 Turn on the both check boxes for the low and high herbicide level. Click [Next]
 Turn on the both check boxes for the low and high biocide level. Click [Next]
LUCTOR will now automatically start to calculate the technical coefficients for the
selected options. When finished the file ANN_IO.XLS will be the active worksheet
containing the technical coefficients. The technical coefficients are similarly structured as in
exercise 1 (see Annex III for a complete overview for codes of cropping systems).
 Fill in Table 5.2 the technical coefficients for the different alternative maize systems.
Compared to Table 5.1 a column is added that indicates the use of crop protection agents
(herbicides and biocides) and is expressed in terms of active ingredients per ha. The
higher this value is, the worse it is supposed to be for the environment.
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Table 5.2. Yield export quality product (EXP in kg/ha/yr), labor required (CLABA in
d/ha/mth costs (CCOST in colon/ha/yr), Nitrogen balance (NBAL in kg N/ha/yr), and use of
crop protection agents (BIOA in kg a.i./ha/yr) of simulated alternative systems.
cropping system code:
EXP
CLABA
CCOST
NBAL
BIOA
SFW.ZM.F9HHH.01
SFW.ZM.F9LHH.01
SFW.ZM.F9HLH.01
SFW.ZM.F9LLH.01
SFW.ZM.F9HHL.01
SFW.ZM.F9LHL.01
SFW.ZM.F9HLL.01
SFW.ZM.F9LLL.01
 Study the results obtained from the various management options with LUCTOR in Table
5.2. Note the yield reductions of the low biocide and mechanization options compared to
a high input level of these production factors. Note also the reduction in chemical crop
protection agents (BIOA) for land use systems with a low biocide and herbicide option.
The first four land use systems show the high costs of mechanization compared to the last
four that require less machinery. In this respect it is obvious that labor requirements are
higher in the last four land use systems.
5.4 Exercise 3: Comparing crops
This exercise will show the user differences among crops. Also technical coefficients of
perennial crops will be generated to show their high costs, labor requirements and use of crop
protection agents compared to annual crops. This exercise will also acquaint the user with
another automation part of LUCTOR. Since for the generation of technical coefficients of
annuals, pineapple, perennials and timber different files are required a custom made shell is
made that allows to switch quickly and automatically between different types of crops. It
closes files that are not required and opens other files required for other crops. This shell was
briefly introduced in section 5.1 to start LUCTOR.
To allow comparison among crops, land use systems with similar criteria options are
generated: alternative-cropping systems at soil fertile well drained soils, crop residues left in
the field, with a high use of biocides, herbicides and mechanization.
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 Start from where you finished exercise 2. First, we are going to generate technical
coefficients for annual crops.
 Press [Ctrl+s] to activate the dialogue boxes with the definition criteria and their options.
The first dialogue box asks the user to define the type of activity. Turn on the check box
for alternative activities and turn off the check box for actual activities. Click [Next].
 Turn on the check box for 100% of the target yield and click [Next].
 Turn on the check box for all crops. Click [Next]
 Turn on the check box for Soil Fertile Well drained. Click [Next]
 Turn on the check box only for the high mechanization level. Click [Next]
 Turn on the check box only for crop residues left in the field. Click [Next]
 Turn on the check boxes only for the high herbicide level. Click [Next]
 Turn on the check boxes only for the high biocide level. Click [Next]
LUCTOR will now automatically start to calculate the technical coefficients for the
selected options. When finished the file ANN_IO.XLS will be the active worksheet
containing the technical coefficients of five different crops, similar as in exercise 1 and 2.
 Fill in Table 5.3 the technical coefficients for the different alternative annual systems.
SFW.ZC.F9HHH.01 (fresh maize cobs) produces not for the export market and the cell
under EXP-column in ANN_IO.XLS is therefore zero. Use in Table 5.3, therefore, the
production for the domestic market (column with DOM as heading).
Subsequently, technical coefficients for pineapple are generated.
 Press [Ctrl+t] to activate the dialogue box with options that allows to switch among crop
types. Select the option ‘Pineapple cropping systems’ by highlighting the option with the
mouse. When highlighted click the [Just do it!] button. LUCTOR will close files that are
no longer required for the generation of technical coefficients of pineapple crops. While
closing files EXCEL returns with a message box asking the user to save the file. Since we
made no structural changes to the files click always on the ‘No’ button. Subsequently,
LUCTOR opens all files required for the generation of technical coefficients for
pineapple cropping systems.
 When LUCTOR has opened all required files the user can view all files that are open by
pressing [Alt+w] or clicking Window in the menu bar. Compare the opened files with the
files shown in Annex II for pineapple crops.
 The user can study briefly the content of the newly opened files. Switch to another file
using [Alt+w] and click the required filename in the file list.
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 After having performed these instructions the user can start to generate technical
coefficients for pineapple systems by activating the dialogue boxes with the definition
criteria. Press [Ctrl+s].
 The first dialogue box asks the user to define the type of pineapple activity. Turn on the
check box for the alternative pineapple activity and click [Next].
 Turn on the check box for 100% of the target yield and click [Next].
 Turn on the check box for both types of pineapple. Click [Next]
 Turn on the check box for Soil Fertile Well drained. Click [Next]
 Turn on the check box for the high mechanization level. Click [Next]
 Turn on the check box for crop residues left at the field. Click [Next]
 Turn on the check boxes for the high herbicide level. Click [Next]
 Turn on the check boxes for the high biocide level. Click [Next]
 Turn on the check boxes for the two-year crop. Click [Next]
LUCTOR will now automatically start to calculate the technical coefficients for the
selected options. When finished the file PIN_IO.XLS will be the active worksheet containing
the technical coefficients, similar as for annual crops.
 Fill in Table 5.3 the technical coefficients for the two alternative pineapple systems. The
land use system with the code SFW.AM.F9HHH (pineapple-local market) produces not
for the export market and the cell under the column EXP in PIN_IO.XLS is therefore
zero. Use in Table 5.3, therefore, the production for the domestic market (column with
DOM as heading).
Subsequently, technical coefficients for three perennial crops are generated.
 Press [Ctrl+t] to activate the dialogue box with options that allows to switch between land
use activities. Select the option ‘Perennial cropping systems’ by highlighting the option
with the mouse. When highlighted click [Just do it!]. LUCTOR will close files that are no
longer required for the generation of technical coefficients of pineapple cropping systems.
While closing files EXCEL returns with a message box asking the user to save the file.
Click always on the ‘No’ button. Subsequently, LUCTOR opens all files required for the
generation of technical coefficients for perennials.
 When LUCTOR has opened all required files the user can view all files that are open by
pressing [Alt+w] or clicking Window in the menu bar. Compare the opened files with the
files shown in Annex II for perennial crops.
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 The user can study briefly the content of the newly opened files. Switch to another file
using [Alt+w] and click the required filename in the file list.
 After having performed these instructions the user can start to generate technical
coefficients for perennial systems by activating the dialogue boxes with the definition
criteria. Press [Ctrl+s].
 The dialogue boxes with the definition criteria come in the same order as for annual and
pineapple systems. Select all perennial crops and the same options as for annuals and
pineapple. Proceed as described for annual and pineapple systems. After the last
definition criteria (Biocide level) LUCTOR will automatically start to calculate the
technical coefficients for the selected options. When finished the file PER_IO.XLS will
be the active worksheet containing the technical coefficients of the perennial systems.
 Fill in Table 5.3 the technical coefficients for the three alternative perennial systems.
Table 5.3. Yield export quality product (EXP in kg/ha/yr), labor required (CLABA in d/ha/mth),
costs (CCOST in colon/ha/yr), use of crop protection agents (BIOA in kg a.i./ha/yr) and Nrequirements (FIN in kg N/ha/yr) of simulated alternative systems.
cropping system code:
EXP
CLABA
CCOST
BIOA
FIN
SFW.ME.F9HHH.01
SFW.OS.F9HHH.01
SFW.PV.F9HHH.01
SFW.ZC.F9HHH.01
*)
SFW.ZM.F9HHH.01
SFW.AC.F9HHH.02
SFW.AM.F9HHH.02
*)
SFW.BG.F9HHH.15
SFW.MA.F9HHH.15
SFW.MB.F9HHH.15
*)
Use the value under the column with DOM in respectively ANN_IO.XLS and
PIN_IO.XLS
 Study the results for the different crops in Table 5.3. Note the large differences in most
technical coefficients among on the one hand pineapple for export purposes (AC), banana
(MA) and plantain (MB) and on the other hand the other crops.
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5.5 Exercise 4: Changes in data base
In this exercise changes will be made in the database to show the effect of data and
underlying assumptions on technical coefficients.
LUCTOR combines measured field data (e.g. soil data and prices), calculation rules (e.g.
nutrient withdrawal of crops) and export knowledge. These latter are by definition arbitrary
assumptions about for instance the attainable yield level, but in case of LUCTOR explicitized
and verifiable. Often these estimates are based on a kind of average yield and neither take into
account risks of crop failures due to unfavorable weather conditions in certain years nor the
opposite, i.e. higher than average yields. LUCTOR formalizes export knowledge in
quantitative characteristics and allows to use other assumptions about for instance the
attainable yield of a crop. Other data used in LUCTOR such as input and output prices can
vary due to e.g. changing market conditions or subsidies. By changing prices in the data files
of LUCTOR cost-benefit analysis can be done using different prices.
In this exercise is examined how certain yield parameters of maize-grain and changes in
input prices affect technical coefficients.
 Start from where you finished exercise 3. Press [Ctrl+t] to activate the dialogue box that
allows to switch among crop types. Select the option ‘annual cropping systems’ by
highlighting the option with the mouse. When highlighted click [Just do it!]. LUCTOR
closes the files that are no longer required and will open files required for generation of
annual crops.
 Press [Ctrl+s] to activate the dialogue boxes with the definition criteria and their options.
The first dialogue box asks the user to define the type of activity. Only turn on the check
box for alternative activities and turn off the check box for actual activities. Click [Next].
 Turn on the check box for 100% of the target yield and click [Next].
 Turn on only the check box for maize-grain. Click [Next]
 Turn on only the check box for Soil Fertile Well drained. Click [Next]
 Turn on only the check boxes for the high mechanization level. Click [Next]
 Turn on only the check boxes for crop residues left on the field. Click [Next]
 Turn on only the check boxes for the high herbicide level. Click [Next]
 Turn on only the check boxes for the high biocide level. Click [Next]
LUCTOR will now automatically start to calculate the technical coefficients for the
selected option. When finished the file ANN_IO.XLS will be the active worksheet containing
the technical coefficients.
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 Fill in the first row of Table 5.4 (‘standard’) the relevant technical coefficients. This
system will be used as a standard to compare with.
 Go to the file ANN_CROP.XLS by pressing [Alt+w] and clicking the filename in the file
list.
 Go to the worksheet ‘crop’ by clicking the tab at the bottom of your screen.
 Go to cell F9, which contains the maximum attainable target yield for alternative maize
activities. In the standard setting it is 6.8 ton/ha. Change this yield in 9 ton/ha. Enter 9
 Subsequently, press [Ctrl+s] to activate the dialogue boxes with the definition criteria and
their options. Turn on the check box for alternative activities and turn off the check box
for actual activities. Turn on the same check boxes as in the “standard” (see above). After
the last dialogue box LUCTOR will automatically start to calculate technical coefficients
for the selected option.
 Fill in the second row of Table 5.4 (‘higher target yield’) the relevant technical
coefficients.
 Go to the file ANN_CROP.XLS by pressing [Alt+w] and clicking the filename in the file
list.
 Set cell F9 back to its original value of 6.8 ton ha-1.
 Go to cell F117, which contains the labor requirements for harvesting maize. In the
standard setting it is 75 kg dm h-1. Reduce the amount harvested with 50%. Enter 37.5.
 Subsequently, press [Ctrl+s] to activate the dialogue boxes with the definition criteria and
their options. Proceed as described above. After the last dialogue box (definition criteria
for biocide level) LUCTOR calculates the same land use system with the new labor
requirements for harvesting.
 Fill in the third row of Table 5.4 (‘higher labor requirements’) the relevant technical
coefficients.
 Go to the file ANN_CROP.XLS by pressing [Alt+w] and clicking the filename in the file
list.
 Set cell F117 back to its original value of 75 kg h-1.
 Go to file PRICE.XLS by pressing [Alt+w] and clicking the filename in the file list.
 Go to cell E19which contains the price for Nitrogen fertilizer. Double the price for
Nitrogen and change it into 360 col/kg. Do the same for cells E20and E21 which contain
prices for Phosphor and Potassium fertilizer. Change the price of Phosphor into 780
col/ha and of Potassium into 256 col/ha.
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 Subsequently, press [Ctrl+s] to activate the dialogue boxes with the definition criteria
and their options. Proceed as described above. After the last dialogue box (definition
criteria for biocide level) LUCTOR calculates the same system with the new fertilizer
prices.
 Fill in the fourth row of Table 5.4 (‘higher fertilizer prices’) the relevant technical
coefficients.
Table 5.4. Yield export quality product (EXP in kg/ha/yr), labor required (CLABA in d/ha/mth),
costs (CCOST in colon/ha/yr) and N-requirements (FIN in kg N/ha/yr) of simulated alternative
systems.
cropping system name:
EXP
CLABA
CCOST
FIN
Standard
Higher target yield
Higher labor requirements
Higher fertilizer prices
 Study the results in Table 5.4 and note how changes in different parameters affect
technical coefficients differently. It is obvious that different technical coefficients used in
linear programming models in distinct optimization values result. A sensitivity analysis of
the LP-model with different technical coefficients is therefore a necessity for a sound
interpretation of LP-results.
When finished with the exercises, close LUCTOR by pressing [Ctrl+t], select ‘close all files’
and subsequently click the [Just do it!] button. All files will be closed. Do not save any
changes to the files.
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ANNEX I Files used by LUCTOR and their content
Type of file:
Filename and content:
Data files
BASIC.XLS = parameters concerning climate and environment
SOIL.XLS = soil and crop suitability parameters, and timber production
parameters
PER_CROP.XLS = perennial crop parameters
ANN_CROP.XLS = annual crop parameter
PROTECT.XLS = lists of biocides, their characteristics and price
PRICE.XLS = prices of outputs and inputs (except for biocides)
LIST.XLS = definition criteria and lists with files required for each type of
crop activity, plus (hidden) visual basic modules
Calculation files
ANNUAL.XLS = calculations for annual cropping systems
PINA.XLS = calculations for pineapple cropping systems
PERENIAL.XLS = calculations for perennial cropping systems
FOREST.XLS = calculations for timber cropping systems
files with results
ANN_IO.XLS = technical coefficients of annual cropping systems
PIN_IO.XLS = technical coefficients of pineapple cropping systems
PER_IO.XLS = technical coefficients of perennial cropping systems
FOR_IO.XLS = technical coefficients of timber cropping systems
Files used for each type of cropping system
Name of file:
annuals: beans,
Pineapple
rice, maize, cassava
perennials: banana,
timber: melina,
plantain, palmheart teak, natural forest
BASIC.XLS
X
X
X
X
SOIL.XLS
X
X
X
X
X
X
X
PER_CROP.XLS
ANN_CROP.XLS
X
PROTECT.XLS
X
X
X
X
PRICE.XLS
X
X
X
X
LIST.XLS
X
X
X
X
ANNUAL.XLS
X
PINA.XLS
PERENIAL.XLS
X
X
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FOREST.XLS
ANN_IO.XLS
PIN_IO.XLS
PER_IO.XLS
FOR_IO.XLS
X
X
X
X
X
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Annex II
Technical Coefficients of cropping systems
Description of technical coefficient
Unit
Code
Export quality product
kg/ha/yr
EXP
Domestic quality product
kg/ha/yr
DOM
Refuse product
kg/ha/yr
REF
Labor requirements – discounted annuity
mnd/ha/mth
CLABA
Labor requirements – mean
mnd/ha/mth
CLABM
Costs (do not include costs for labor)
col/ha/yr
CCOST
N-balance
kg N/ha/yr
NBAL
P-balance
kg P/ha/yr
PBAL
K-balance
kg K/ha/yr
KBAL
Volatilization
kg N/ha/yr
NVOL
Denitrification
kg N/ha/yr
NDEN
N-Leaching
kg N/ha/yr
NLEA
Biocide index
BIOI
Biocide use
kg ai/ha/yr
BIOA
Fertilizer N-input
kg N/ha/yr
FIN
Fertilizer P-input
kg P/ha/yr
FIP
Fertilizer K-input
kg K/ha/yr
FIK
P-fixation
kg P/ha/yr
PFIX
K-leaching
kg K/ha/yr
KLEA
Tractor use
trdays/ha/yr
TRAC
Sowing equipment use
Seqdays/ha/yr
SOWE
Multicultivator equipment use
Meqdays/ha/yr
MULT
Fertilizer spreader use
feqdays/ha/yr
FEQ
Knapsack sprayer use
Keqdays/ha/yr
BOMB
Seedlings/seed
#/ha or kg/ha
SEED
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Annex III Identification codes of cropping systems
Cropping systems have an identification code, for example: SFP.ZM.F9HHL.01
code 1: Soil type can be:
SFW = Soil fertile well drained
SIW = Soil infertile well drained
SFP = Soil fertile poorly drained
code 2: Crop type can be:
AC = pineapple for export
AM = pineapple for local market
BG = palmheart
GA = melina
MA = banana
MB = plantain
ME = cassava
OS = rice
PV = beans
SN = natural forest
TG = teak
ZM = maize grain
ZC = maize fresh cobs
code 3: Combination of type of land use system, target yield level, biocide level, herbicide
level and mechanization level.
First letter plus number: type of land use activity plus yield level. F0 stands for actual
activity, F1...F9 stands for alternative activities in which F9 is the maximum level and F1
is 20% of this level.
Second letter: biocide level (L = low, H = high)
Third letter: herbicide level (L = low, H = high)
Fourth letter: mechanization level (L = low, H = high)
code 4: The length of a cropping cycle. For annual cropping systems 01 year, for
pineapple 01 or 02 years, for perennials 15 years.
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Annex IV Installing procedure for LUCTOR
Create two directories on your hard disk with a file manager. One directory is for the
LUCTOR files and one is for the files with technical coefficients that can be custom-made
generated for the REALM-model (see Chapter 6 of book). Be aware that when using the latter
feature of LUCTOR, each time it is run, files in this directory will be deleted (see also
Chapter 3 in Hengsdijk et al. (1998))!
Copy the LUCTOR files to the directory specified for LUCTOR. Open LIST.XLS.
Automatically an input box is activated to enter the name of the directory for the LUCTOR
files. Press [Return] or click the OK-button after having filled in the directory name. A new
input box will appear asking you to fill in the directory name for the customized output files
for the REALM-model. Fill in the name and press [Return] or click the OK-button. The
installation procedure is finished after having saved LIST.XLS.
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