APPENDIX K.
PRZM IN FOCUS USER MANUAL
Please Note:
This user manual was published together with all
available documentation on 15 May 2003.
Therefore, it may not contain the most recent
information as the models and the shells may have
changed with time.
Make sure that you always have the most recent
version available, which may be obtained from the
web site of JRC, Ispra, Italy:
http://viso.ei.jrc.it/focus/
1
1 Introduction
A modified and improved PRZM code (version 3.22, FOCUS release) is used with the PRZM in
FOCUS surface water runoff shell.
The original PESTICIDE ROOT ZONE MODEL executable PRZM31.EXE ran under Microsoft
DOS. In order to realise a truly Windows-based version of this model, the program was recoded and
compiled with a 32-bit FORTRAN compiler. The new executable, WINPRZM.EXE, is now free of
all DOS limitations. A new windows shell, called PFSW.EXE (for PRZM in FOCUS, SURFACE
WATER), was built around the new PRZM executable to facilitate the creation of of PRZM input
files. The shell is optimized for a screen resolution of 1024x768 pixels and provides the following
features:
 User-friendly scenario and parameter definitions in a Microsoft Windows environment
 Pre-defined scenario inputs for four FOCUS European runoff and erosion scenarios
 Modified and enhanced PRZM31 code (Version 3.22, FOCUS release)
Three types of input files are required to run PRZM31.EXE:
 Meteorological files providing the weather data (*.met)
 Scenario files providing the chemical, cropping, agronomic, soil and use data (*.inp)
 Run files providing various PRZM run options (*.run)
When the user selects the desired crop(s) and scenario(s) and enters the required chemical input data,
the PFSW shell automatically generates the required input files in a project directory.
After a completed simulation run, the relevant scenario output data are given a set of ASCII files with
specific file types:
 hydrologic mass balance files:
*.out (for all 20 years of simulation)
*.hyd (for selected 12 month period of simulation)
*.hy2 (for application portion of selected 12 month period of simulation)
 chemical mass balance files:
*.out (for all 20 years of simulation)
*.msb (for selected 12 month period of simulation)
*.ms2 (for application portion of selected 12 month period of simulation)
 daily runoff and erosion output files:
*.zts (for all 20 years of simulation – this file is not currently used by FOCUS)
*. p2t (for selected 12 month period of simulation) – this file is read by TOXSWA
 graphical support files:
*.scn files (supports the use of the grapher in the PRZM in FOCUS shell)
When the grapher feature in the PRZM in FOCUS shell is used, the *.scn files are analyzed
automatically to provide the user with appropriate result tables and graphs for each parent and
metabolite being simulated.
The parameters that are used in the PRZM in FOCUS shell are divided into four categories:
FOCUS DEFINITION:
general parameter values agreed upon by the FOCUS working group
parameter values that have been fixed for each scenario
DEVELOPMENT DEFINITION: parameter values that have been fixed to select model options
USER INPUT: parameter values that are entered by the user, either from experimental data or from a
defined list of choices
FOCUS SCENARIO SPECIFIC:
For Step 3 simulations of runoff and erosion, the values of the parameters listed as FOCUS DEFINITION,
FOCUS SCENARIO SPECIFIC and DEVELOPMENT DEFINITION should not be changed by the user of the
PRZM in FOCUS shell.
2
If the user finds it necessary to perform more refined runoff and erosion calculations beyond Step 3, it
is possible to manually edit the *.inp files created by the PRZM in FOCUS shell and rerun the various
scenarios. If any modifications are made to any of the shell-generated data files, the changes should
be clearly described in the resulting modeling report and the results should be referred to as Step 4
simulations.
Customized modifications of the data files beyond Step 3 are appropriate to address such things as:
 Unusual cropping sequences (Step 3 assumes no cropping rotation)
 Effect of landscape mitigation factors such as non-cropped buffer strips
 Simulation of crops not included in the PRZM in FOCUS shell
 Simulation of runoff scenarios not provided in the present PRZM in FOCUS shell
3
2 Parameter description
PARAMETER AND DESCRIPTION
Meteorological files
VALUE, SOURCE AND COMMENTS
MMDDYY: meteorological month/day/year
The PRZM in FOCUS shell includes 4 non-irrigated location specific
PRECIP:
precipitation (cm/day)
meteorological files (e.g. R1NOIRR.MET for scenario R1) and 32
PEVP:
pan evaporation (cm/day)
irrigated location and crop specific meteorological files (e.g.
TEMP:
temperature (Celsius)
R1MAIZE.MET for maize in scenario R1). All files cover the period 1
WIND:
wind speed (cm/sec)
Jan 1975 to 31 Dec 1994 and are in the format required by PRZM.
SOLRAD:
solar radiation (Langley)
Record 1
TITLE: label for simulation title
FOCUS SCENARIO SPECIFIC
Record 2
HTITLE: label for hydrology information title
FOCUS SCENARIO SPECIFIC
Record 3
PFAC: pan factor used to estimate the daily
FOCUS DEFINITION – crop specific values are listed in Table D1.
potential evapotranspiration (ET) from daily
Values are consistent with FOCUS groundwater report
pan evaporation.
FOCUS DEFINITION – set to 0.20. SFAC is an empirical factor with
SFAC: snowmelt factor in cm/degrees
wide variation. This value has been set at a minimum value to help
Celsius above freezing
ensure reasonable hydrologic flows in TOXSWA using the FOCUS
scenarios.
IPEIND: pan factor flag
DEVELOPMENT DEFINITION – set to 0, indicating that daily pan
evaporation data is read from the meteorological file
ANETD: minimum depth from which
FOCUS DEFINITION – various values. ANETD is location specific and
evaporation is extracted
is highly correlated to climatic conditions. Based on the US distribution
map and the relevant 20 year average annual air temperature, the
following values have been set for the FOCUS runoff scenarios:
R1 (Weiherbach)
10.0 oC
15 cm
R2 (Porto)
14.8 oC
25 cm
o
R3 (Bologna)
13.5 C
25 cm
R4 (Roujan)
14.0 oC
25 cm
Comment: This value helps determine soil evaporative losses during
fallow periods. When crops are present, evapotranspirative demand
occurs from the surface to the current rooting depth.
INICRP: flag for initial crop
DEVELOPMENT DEFINITION – set to 1, indicating initial crop
ISCOND: surface condition of initial crop
DEVELOPMENT DEFINITION – set to 1, indicating fallow
Record 6
ERFLAG: flag to select simulation of erosion
DEVELOPMENT DEFINITION – set to 4, indicating use of MUSS
equation, the soil loss equation appropriate for small watersheds
Record 7
USLKEK: soil erodibility factor for MUSS
FOCUS SCENARIO SPECIFIC – see scenario-specific soil data in
USLELS: topographic factor for MUSS
D14, D15, D16 and D17
USLEP:
practice factor for MUSS
AFIELD: field area for MUSS
IREG:
SCS rainfall distribution region
SLP:
land slope (%)
HL:
hydraulic length (m)
4
Record 8
NDC: number of different crops in simulation
DEVELOPMENT DEFINITION – set to 1, only one crop in simulation
Record 9
ICNCN: crop number
DEVELOPMENT DEFINITION – set to 1
CINTCP: maximum interception storage
FOCUS DEFINITION – see crop-specific data (Table D1)
AMXDR: maximum rooting depth of crop
FOCUS SCENARIO SPECIFIC – see crop and scenario-specific data
(Tables D3, D6, D9 and D12)
COVMAX: maximum canopy coverage
FOCUS DEFINITION – see crop-specific data (Table D1)
ICNAH: surface condition after harvest
DEVELOPMENT DEFINITION – set to 3 = residue
CN: runoff curve numbers for fallow,
FOCUS SCENARIO SPECIFIC – see crop-and-scenario-specific data
cropping and residue
(Tables D4, D7, D10 and D13)
(Note: for runoff simulations, CN values are read from Record 9E)
WFMAX: maximum dry wt of crop
DEVELOPMENT DEFINITION – set to 0, option not used in FOCUS
HTMAX: max canopy at maturation date
FOCUS DEFINITION – see crop-specific data (Table D1)
Record 9A
CROPNO: crop number
DEVELOPMENT DEFINITION – set to 1
NUSLEC: number of sets of erosion factors
DEVELOPMENT DEFINITION – set to 4 (emergence, maturation,
harvest, fallow)
Record 9B (four dates)
Dates for each set of erosion factors:
FOCUS SCENARIO SPECIFIC - see crop-and-scenario-specific data
EMD, EMM (emergence)
(Tables D3, D6, D9 and D12); also see Record 11 for cropping dates
MAD, MAM (maturation)
Note: order of dates begins with crop emergence
HAD, HAM (harvest)
GDUSLEC / GMUSLEC (fallow)
Record 9C (four values)
USLEC: universal soil loss cover
FOCUS DEFINITION – see crop-specific data (Table D1)
management factors
Note: values correspond to dates in Record 9B
Record 9D (four values)
MNGN: Manning’s roughness coefficient
FOCUS SCENARIO SPECIFIC – see scenario-specific soill data
(Tables D14, D15, D16 and D17)
Note: values correspond to dates in Record 9B
Record 9E (four values)
CN: runoff curve numbers of antecedent
FOCUS SCENARIO SPECIFIC – see crop-and-scenario specific data
moisture condition II for fallow, cropping and
(Tables D4, D7, D10 and D13)
residue
Note: values correspond to dates in Record 9B
Record 10
NCPDS: number of cropping periods
DEVELOPMENT DEFINITION – set to 20 for most crop/scenarios; set
to 40 for leafy vegetables in R1-R4 and for root vegetables in R2
Record 11
EMD, EMM, IYREM: crop emergence date
FOCUS SCENARIO SPECIFIC – see Tables D3, D6, D9 and D12
(month/day/year)
MAD, MAM, IYRMAT: crop maturation date
FOCUS SCENARIO SPECIFIC – see Tables D3, D6, D9 and D12
HAD, HAM, IYRHAR: crop harvest date
FOCUS SCENARIO SPECIFIC – see Tables D3, D6, D9 and D12
INCROP: crop number associated with NDC
DEVELOPMENT DEFINITION – set to 1 (only one crop)
Record 13
NAPS: total number of applications
USER INPUT – user specifies number of applications per year in
occurring at different dates (max: 50)
Pesticide Application Tool (PAT) in PRZM in FOCUS shell (max: 20/yr)
NCHEM: number of chemicals in simulation
USER INPUT
set to 1 = parent only
set to 2 = parent with one metabolite
set to 3 = parent with two metabolites
FRMFLG: flag for testing of ideal soil
DEVELOPMENT DEFINITION – set to 0 (PRZM soil moisture test not
moisture conditions for application
used)
DKFLG2: flag to allow input of biphasic
USER INPUT – set to 0 as default (no biphasic half-life); PRZM in
5
degradation half-life
FOCUS shell also permits option of biphasic half-life (set to 1)
Record 15
PSTNAM: name of chemical(s) for output file
USER INPUT
Record 16
AP_DDMMYY: target application dates
USER INPUT – user enters data in Pesticide Application Tool (PAT) in
PRZM in FOCUS shell to select application dates. Required inputs are:
application date (relative to crop emergence)
WINDAY: number of days in which to check
minimum application window (days)
soil moisture following target date
DEVELOPMENT DEFINITION – set to 0 (option not used)
CAM: flag set to select application method
USER INPUT – selectable chemical application methods (CAM) are:
1 = soil applied, default application depth = 4 cm, linearly decreasing
with depth. This is the DEFAULT for use with FOCUS scenarios;
2 = crop canopy, default soil incorporation depth for non-foliar
intercepted chemical is 4 cm, linearly decreasing w/ depth;
3 = non-linear foliar using exponential filtration, same default soil
incorporation as in CAM=2 (option not used in FOCUS);
DEPI: incorporation depth of application (cm)
4 = soil applied, user defined incorporation depth (DEPI), uniform with
depth;
5 = soil applied, user defined incorporation depth (DEPI), linearly
increasing with depth;
6 = soil applied, user defined incorporation depth (DEPI), linearly
decreasing with depth;
7 = soil applied, T-band granular application, user defined incorporation
depth;
8 = soil applied, chemical incorporated entirely into depth specified by
user.
Notes: to prevent an over-prediction of runoff, a default DEPI value of 4
cm (linearly decreasing with depth) is used for Step 3 modeling; DEPI
> 0 for CAM 4 to 8; metabolite CAM = 0
TAPP: target application rate (kg as/ha)
USER INPUT
APPEFF: application efficiency (fraction)
FOCUS DEFINITION – set to 1.0 (conservative assumption within field)
DRFT: spray drift (fraction)
DEVELOPMENT DEFINITION – set to 0, drift values used by TOXSWA
are calculated by drift calculator in SWASH
Record 17
FILTRA: filtration parameter (for CAM 3)
DEVELOPMENT DEFINITION – set to 0 (option not used in FOCUS)
IPSCND: disposition of pesticide after
DEVELOPMENT DEFINITION – set to 1 (surface applied)
harvest
UPTKF: plant uptake factor (varies between
USER INPUT – set to 0.5 for systemic compounds (default); set to 0
0 and 1; describes uptake as a fraction of
for compounds which are not systemic (no uptake)
transpiration * dissolved phase concentration
Record 18
(Only if CAM = 2 or 3, repeat for NCHEM)
PLVKRT: pesticide volatilization rate on
DEVELOPMENT DEFINITION – set to 0 (parameter not used)
foliage (days-1)
PLDKRT: pesticide dissipation rate of foliage
USER INPUT – set to sum of volatilization and degradation rate
(days-1)
(implies degradation products not specified or tracked)
FEXTRC: foliar washoff coefficient (cm-1)
USER INPUT – set to 0.1 (default); other values can be used based on
experimental data
Record 18A
Only if CAM=2 or 3 and NCHEM > 1
PTRAN12: foliar transformation rate for
DEVELOPMENT DEFINITION – set = 0; tracking of foliar
chemical 1 to 2
transformation to specific metabolites not included in FOCUS scenarios
6
PTRAN13: foliar transformation rate for
DEVELOPMENT DEFINITION – set = 0; tracking of foliar
chemical 1 to 3
transformation to specific metabolites not included in FOCUS scenarios
PTRAN23: foliar transformation rate for
DEVELOPMENT DEFINITION – set = 0; tracking of foliar
chemical 2 to 3
transformation to specific metabolites not included in FOCUS scenarios
Record 19
STITLE: label for soil properties title
FOCUS SCENARIO SPECIFIC
Record 20
CORED: total depth of soil core (cm)
FOCUS SCENARIO SPECIFIC – set to 100-300 cm (see Tables D14,
D15, D16 and D17)
BDFLAG: bulk density flag
DEVELOPMENT DEFINITION – set to 0, bulk density directly entered
THFLAG: field capacity & wilt point flag
DEVELOPMENT DEFINITION – set to 0, soil moisture defined for each
scenario
KDFLAG: soil adsorption flag (use of KD or
USER INPUT - set to 0, 2 or 3 (option 1 not used)
Koc, use of linear sorption, Freundlich
0 = linear sorption
sorption with Cref = 1 mg/L and/or aged
If KDFLAG = 0 and KD is entered in the PRZM in FOCUS shell, a
sorption)
uniform value of KD is assigned to the entire soil profile and entered on
Record 37
If KDFLAG = 0 and Koc is entered in the PRZM in FOCUS shell, a layer
specific KD is calculated based on Koc and OC and the value is
entered on Record 37
2 = normalised Freundlich equation
If KDFLAG = 2 and KD is entered, a uniform value of KD is assigned to
the entire soil profile and entered on Record 37; Freundlich 1/n is
entered in Record 30b
If KDFLAG = 2 and Koc is entered, a layer specific KD is calculated
based on Koc and OC and the value is entered on Record 37;
Freundlich 1/n value(s) are entered on Record 30b
3 = aged sorption
compound specific ageing factors are defined in Record 30c and
applied to calculate aged sorption on a daily basis. Normalised
Freundlich equation is used in the same way as described for 2.
HSWZT: drainage flag
DEVELOPMENT DEFINITION – set to 0 (free drainage assumed)
MOC: method of characteristics flag
DEVELOPMENT DEFINITION – set to 0 (MOC not used)
IRFLAG: irrigation flag
DEVELOPMENT DEFINITION – set to 0 (no irrigation simulated)
Necessary irrigation is added to rainfall data
ITFLAG: soil temperature simulation flag
USER INPUT – 0 = temperature and moisture correction off (field
(0 = off; 1 or 2 = on)
degradation data used); 1 = option not used; 2 = temperature and
correction on (lab degradation data used)
IDFLAG: therm cond & heat capacity flag
DEVELOPMENT DEFINITION – set to 1 (model simulates temperature
profile using default thermal conductivity and heat capacity)
BIOFLG: biodegradation flag
DEVELOPMENT DEFINITION – set to 0 (microbial population
degradation algorithms not used)
Record 26
DAIR: molecular diffusion coefficient for the
FOCUS DEFINITION – set to 4300 cm2/day for parent and metabolites
pesticide(s) in air
HENRYK: normalised Henry’s law constant
USER INPUT – values for vapor pressure, molecular weight and water
of the pesticide(s) – dimensionless
solubility are required; HENRYK = P * M * 1000 / (C * R * T) where
P = vapor pressure (mPa)
M = molecular weight (g/mol)
C = water solubility (mg/L)
R = gas constant = 8.314 J / (mol K) = 8.314 x 10-3 L mPa/ (mol K)
T = absolute temperature (K)
ENPY: enthalpy of vaporisation of the
FOCUS DEFINITION – set to 22.7 kcal/mol (agrees with FOCUS gw
7
pesticide(s) (kcal/mole)
and TOXSWA)
Record 30 (only if KDFLAG=2, 3)
FRNDCF: Freundlich exponent 1/n
USER INPUT
(dimensionless)
The reference concentration Cref is fixed in the PRZM code to 1 mg/L.
The use of the Freundlich isotherm is limited to dissolved phase
concentrations higher than 0.01 ug/L.
Record 30c (only if KDFLAG=3)
Five pairs of time points (BAKD, VADK) are
USER INPUT - FOCUS default = not used
used to define aged sorption, with units of
Aged sorption is not to be used in the FOCUS scenarios unless
(days, relative sorption value)
experimental data is available.
Comment: Aged sorption is described with a dimensionless time-
BAKD = ageing time (days after application)
dependent ageing factor > 1. An ageing effect is often relevant for the
VADK = KDaged / KDinitial (relative sorption
pehavior of pesticides in soil and may be calculated from standard
factor, dimensionless)
adsorption/desorption studies as specifed from the OECD (1997).
PRZM calculates the ageing factor on a daily basis by linear
interpolation of the specified data and is limited to the last of the five
VADK numbers. After each application period, the ageing period is
reset to zero to prevent overprediction of the effect of ageing.
Record 31 (only if ITFLAG =1, 2)
ALBEDO: monthly values of soil surface
FOCUS DEFINITION – set to 12 monthly values of 0.18 (average for a
albedo – 12 values required
range of normal field conditions); agrees with FOCUS gw
EMMISS: reflectivity of soil surface to
FOCUS DEFINITION – set to 0.96 (average for natural surfaces at
longwave radiation (fraction)
normal temperatures); agrees with FOCUS gw
ZWIND: height of wind speed measurement
FOCUS DEFINITION – set to 10 m; agrees with FOCUS gw
above the soil surface (m)
Record 32 (only if ITFLAG = 1, 2)
BBT: average monthly values of bottom
FOCUS SCENARIO SPECIFIC – annual average air temperature used
boundary soil temperatures in degrees
as constant bottom boundary condition:
R1: 10.0 oC
Celsius (12 values)
o
R2: 14.8 C
R3: 13.5 oC
R4: 14.0 oC
Record 32a (only if ITFLAG = 2)
QFAC: Q10-factor for determining
FOCUS DEFINITION – set to 2.2 (corresponding to activation energy of
degradation rate increase when temperature
54 kJ/mole, the mean value endorsed by FOCUS)
increases by 10 oC
TBASE: reference temperature for
USER INPUT
degradation data
Record 32b (only if ITFLAG = 2)
ABSREL: flag for type of reference soil
USER INPUT – 1 = reference soil moisture entered in absolute terms;
moisture data
2 = reference soil moisture entered relative to field capacity
B-VALUE: exponent for moisture correction
FOCUS DEFINITION – set to 0.7 as default
REFMOIST: reference moisture correction
USER INPUT – if ABSREL = 1, enter value as V/V %; if ABSREL = 2,
for degradation data
enter value as percent of field capacity
Record 33
FOCUS SCENARIO SPECIFIC – see Tables D14, D15, D16 and D17
NHORIZ: total number of horizons
Record 34 (repeat Records 34-38 up to
NHORIZ)
HORIZN: horizon number in
FOCUS SCENARIO SPECIFIC
THKNS: thickness of the horizon
FOCUS SCENARIO SPECIFIC – see Tables D14, D15, D16 and D17
FOCUS SCENARIO SPECIFIC – see Tables D14, D15, D16 and D17
BD: soil dry bulk density (g/cm3)
3
3
THETO: initial soil water content (cm / cm )
FOCUS SCENARIO SPECIFIC – set to field capacity for scenario and
horizon; see Tables D14, D15, D16 and D17
AD: soil drainage parameter (day-1)
DEVELOPMENT DEFINITION – set to 0 (option not used)
DISP: pesticide(s) hydrodynamic dispersion
DEVELOPMENT DEFINITION – set to 0 (parameter not used)
8
coefficient (cm2/day)
ADL: lateral soil drainage parameter (day-1)
DEVELOPMENT DEFINITION – set to 0 (option not used)
Record 36 (for DKFLG2 = 0)
DWRATE: dissolved phase pesticide(s)
USER INPUT – pesticide degradation half-life entered by user; PRZM
degradation rate for first phase of bi-phase
in FOCUS shell calculates DWRATi = DSRATi = ln (2) / pesticide
reaction (day-1)
degradation half-life; DGRATi is set to 0
DSRATE: adsorbed phase pesticide(s)
Note: These degradation rates represent the degradation rate of the
degradation rate for first phase of bi-phase
parent compound. For an explanation of how the degradation rates of
reaction (day-1)
metabolites is handled, see Record 39.
DGRATE: adsorbed phase pesticide(s)
degradation rate for first phase of bi-phase
reaction (day-1)
Record 36 (for DKFLG2 = 1)
DWRAT1: dissolved phase pesticide(s)
USER INPUT – pesticide degradation half-life entered by user; PRZM
degradation rate for first phase of bi-phase
in FOCUS shell calculates DWRAT1 = DSRAT1 = ln (2) / pesticide
-1
degradation half-life; DGRAT1 is set to 0
reaction (day )
DSRAT1: adsorbed phase pesticide(s)
Note: These degradation rates represent the degradation rate of the
degradation rate for first phase of bi-phase
parent compound. For an explanation of how the degradation rates of
reaction (day-1)
metabolites is handled, see Record 39.
DGRAT1: adsorbed phase pesticide(s)
degradation rate for first phase of bi-phase
reaction (day-1)
Record 36a (for DKFLG2 = 1)
DWRAT2: dissolved phase pesticide(s)
USER INPUT – pesticide degradation half-life entered by user; PRZM
degradation rate for first phase of bi-phase
in FOCUS shell calculates DWRAT2 = DSRAT2 = ln (2) / pesticide
-1
degradation half-life; DGRAT2 is set to 0
reaction (day )
DSRAT2: adsorbed phase pesticide(s)
Note: These degradation rates represent the degradation rate of the
degradation rate for first phase of bi-phase
parent compound. For an explanation of how the degradation rates of
reaction (day-1)
metabolites is handled, see Record 39.
DGRAT2: adsorbed phase pesticide(s)
degradation rate for first phase of bi-phase
reaction (day-1)
Record 37 For each horizon,
DPN: thickness of compartments (cm)
FOCUS DEFINITION – set to 0.1 cm for 0-10 cm depth; set to 5 cm for
> 10 cm depth
3
3
THEFC: field capacity (cm / cm )
FOCUS SCENARIO SPECIFIC – see Tables D14, D15, D16 and D17
THEWP: wilting point (cm / cm )
FOCUS SCENARIO SPECIFIC – see Tables D14, D15, D16 and D17
OC: organic carbon (percent)
FOCUS SCENARIO SPECIFIC – see Tables D14, D15, D16 and D17
KD: layer-specific partition coefficient for
USER INPUT – determined from KDFLAG and user input values
3
3
each NCHEM (L/kg)
Record 38 (only if ITFLAG = 1, 2)
For each horizon,
SPT: initial temperature (Celsius)
FOCUS SCENARIO SPECIFIC – set to BBT (see Record 32)
SAND: sand content (percent)
FOCUS SCENARIO SPECIFIC – see Tables D14, D15, D16 and D17
CLAY: clay content (percent)
FOCUS SCENARIO SPECIFIC – see Tables D14, D15, D16 and D17
THCOND: thermal conductivity
DEVELOPMENT DEFINITION – set to 0; default values used
o
(cal/ cm day C)
(IDFLAG = 1)
VHTCAP: heat capacity per unit volume
DEVELOPMENT DEFINITION – set to 0; defaults value used
(cal/ cm3 oC)
(IDFLAG = 1)
Record 39 (Only if NCHEM > 1 and
DKFLG2 = 0)
DKRW12: Degradation conversion factor for
USER INPUT – for each chemical species, the user enters the
chemical 1 to 2 in solution phase
molecular weight; for each reaction, the user enters the degradation
9
DKRW13: Degradation conversion factor for
half-life and molar conversion factor (C factor) for the reaction; The
chemical 1 to 3 in solution phase
PRZM in FOCUS shell calculates a degradation conversion factor for
DKRW23: Degradation conversion factor for
each reaction and enters the results on Record 39.
chemical 2 to 3 in solution phase
Example:
DKRS12: Degradation conversion factor for
For the reaction of chemical 1 (MW 300) to chemical 2 (MW 286), the
chemical 1 to 2 in sorbed phase
molar conversion factor is 60% (i.e. 60% of the moles of chemical 1
DKRS13: Degradation conversion factor for
degrade to form chemical 2, 40% forms other chemicals):
chemical 1 to 3 in sorbed phase
DKRW12 = DKRS12 = (60/100) * 286 / 300 = 0.572
DKRS23: Degradation conversion factor for
Note: “Maximum percent formed” values are not equivalent to molar
chemical 2 to 3 in sorbed phase
conversion factors. See the help screens of PEARL for additional
clarification
Record 39 (Only if NCHEM > 1 and
DKFLG2 = 1)
Values for first phase of degradation
DKW112: Degradation conversion factor for
USER INPUT – for each chemical species, the user enters the
chemical 1 to 2 in solution phase
molecular weight; for each reaction, the user enters the degradation
DKW113: Degradation conversion factor for
half-life for the first phase of reaction, the time when the reaction rate
chemical 1 to 3 in solution phase
changes and the molar conversion factor (C factor) for the reaction;
DKW123: Degradation conversion factor for
The PRZM in FOCUS shell calculates a degradation conversion factor
chemical 2 to 3 in solution phase
for each reaction and enters the results on Record 39.
DKS112: Degradation conversion factor for
chemical 1 to 2 in sorbed phase
See discussion in Record 39 above.
DKS113: Degradation conversion factor for
chemical 1 to 3 in sorbed phase
DKS123: Degradation conversion factor for
chemical 2 to 3 in sorbed phase
Record 39a (Only if NCHEM > 1 and
DKFLG2 = 1)
Values for second phase of degradation
DKW212: Degradation conversion factor for
USER INPUT – for each chemical species, the user enters the
chemical 1 to 2 in solution phase
molecular weight; for each reaction, the user enters the degradation
DKW213: Degradation conversion factor for
half-life for the first phase of reaction, the time when the reaction rate
chemical 1 to 3 in solution phase
changes and the molar conversion factor (C factor) for the reaction;
DKW223: Degradation conversion factor for
The PRZM in FOCUS shell calculates a degradation conversion factor
chemical 2 to 3 in solution phase
for each reaction and enters the results on Record 39.
DKS212: Degradation conversion factor for
chemical 1 to 2 in sorbed phase
See discussion in Record 39 above.
DKS213: Degradation conversion factor for
chemical 1 to 3 in sorbed phase
DKS223: Degradation conversion factor for
chemical 2 to 3 in sorbed phase
Record 40
ILP: flag for initial pesticide concentrations in
DEVELOPMENT DEFINITION – set to 0 (no initial pesticide
soil before start of simulation
concentration in soil profile)
Record 42
Output options
FOCUS DEFINITION – specific output options have been selected to
provide hydrologic, pesticide flux and pesticide concentration output
files that can be reviewed by the user. The selected output files are:
(scenario filename).hyd – hydrologic output file
(scenario filename).msb – pesticide mass balance output file
(scenario filename).cnc – pesticide concentration output file
Record 45
NPLOTS: number of time series plots
FOCUS DEFINITION – set to 6 (1 chem), 8 (2 chem), 10 (3 chem)
STEP4: output time step
FOCUS DEFINITION – set to DAY.
These values create the daily time series output file (scenario
filename.zts) for all 20 years of simulation which is postprocessed by
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the PRZM in FOCUS shell to create the selected 12 month (scenario
filename.p2t) file which is read by TOXSWA
Record 46
RUNF: runoff (mm)
FOCUS DEFINITION – use conv factor of 10 to convert cm to mm
ESLS: erosion (kg)
FOCUS DEFINITION – use conv factor of 1000 to convert tonne to kg
PRCP: daily precipitation (mm)
FOCUS DEFINITION – use conv factor of 10 to convert cm to mm
INFL: daily infiltration below 1m depth (mm)
FOCUS DEFINITION – use conv factor of 10 to convert cm to mm
RFLX1: runoff flux for chem 1 (mg/m2)
FOCUS DEFINITION –use conv factor of 107 to convert g/cm2 to mg/m2
EFLX1: erosion flux for chem 1 (mg/m2)
FOCUS DEFINITION –use conv factor of 107 to convert g/cm2 to mg/m2
RFLX2: runoff flux for chem 2 (mg/m2)
FOCUS DEFINITION –use conv factor of 107 to convert g/cm2 to mg/m2
EFLX2: erosion flux for chem 2 (mg/m2)
FOCUS DEFINITION –use conv factor of 107 to convert g/cm2 to mg/m2
RFLX3: runoff flux for chem 3 (mg/m2)
FOCUS DEFINITION –use conv factor of 107 to convert g/cm2 to mg/m2
EFLX3: erosion flux for chem 3 (mg/m2)
FOCUS DEFINITION –use conv factor of 107 to convert g/cm2 to mg/m2
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