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OREGON APPLES

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The field used to represent apple production in Oregon is located in Marion County, in the Willamette Valley. According to the 1997 Census of Agriculture, Oregon is among the major producers (7th to 8th overall) of apples for the fresh market in the U.S. Within row tree spacing depends on the root stock and cultivation method. Spacing ranges from as little as 5 feet to 25 feet. Row spacing may be as much as twice the within row spacing to allow for maintenance and harvesting equipment. The soil selected to simulate the field is a Cornelius silt loam. Cornelius silt loam, is a fine-silty, mixed, superactive, mesic Mollic Fragixeralfs. The series is used to produce berries, orchards, small grain and seed crop, hay and pasture. Cornelius silt loam is a moderately deep, moderately well drained, moderately slowly permeable soil with slow to medium runoff. The soil has a fragipan at about 2 feet. These soils formed in silt loess-like materials over mixed, fine-silty old alluvium of mixed origin. They are found on gently sloping to rolling low hills ans steep hill slopes with convex, long slopes and ridgetops at elevation of 350 to 800 feet above mean sea level. Slopes range from 2 to 60 percent. The series is not very extensive. Cornelius silt loam is a Hydrologic Group C soil.

Table 1.
PRZM 3.12 Climate and Time Parameters for Marion County Oregon - Apples
ParameterValueSource
Starting Date January 1, 1948Meteorological File - Salem, OR (W24232)
Ending Date December 31, 1983Meteorological File - Salem, OR (W24232)
Pan Evaporation Factor (PFAC) 0.74PRZM Manual Figure 5.1 (EPA, 1998)
Snowmelt Factor (SFAC) 0.15 cm C- 1PRZM Manual Table 5.1 (EPA, 1998)
Minimum Depth of Evaporation (ANETD) 17.0 cmPRZM Manual Figure 5.2 (EPA, 1998)

Table 2.
PRZM 3.12 Erosion and Landscape Parameters for Marion County Oregon - Apples
ParameterValueSource
Method to Calculate Erosion (ERFLAG) 4 (MUSS)PRZM Manual (EPA, 1998)
USLE K Factor (USLEK) 0.33 tons EI-1*Farm Manual, Table 3.1 (EPA, 1985)
USLE LS Factor (USLELS) 3.64Haan and Barfield, 1978
USLE P Factor (USLEP) 1.0Set according to guidance (EPA, 2001)
Field Area (AFIELD) 172 haArea of Shipman Reservoir watershed (EPA, 1999)
NRCS Hyetograph (IREG) 2PRZM Manual Figure 5.12 (EPA, 1998)
Slope (SLP) 12%Value set to maximum for crop (EPA, 2001)
Hydraulic Length (HL) 600 mShipman Reservoir (EPA, 1999)

* EI = 100 ft-tons * in/ acre*hr


Table 3.
PRZM 3.12 Crop Parameters for Marion County Oregon - Apples
ParameterValueSource
Initial Crop (INICRP) 1Set to one for all crops (EPA, 2001)
Initial Surface Condition (ISCOND) 3Set to reside prior to new crop planting; forest floor or meadow.
Number of Different Crops (NDC) 1Set to crops in simulation - generally one
Number of Cropping Periods (NCPDS) 36Set to weather data. Salem, OR (W24232)
Maximum rainfall interception storage of crop (CINTCP) 0.25Set to default for orchards (EPA, 2001)
Maximum Active Root Depth (AMXDR) 45 cm Set to this limit due to soil fragipan. Some limited roots may tap below the top of the fragipan.
Maximum Canopy Coverage (COVMAX) 98 http://caf.wvu.edu/kearneysville/fruitloop.html Exit EPA Disclaimer Ross Byers, Horticultural Specialist VPI - canopy somewhat open between rows; 98% reasonable upper end estimate for the region
Soil Surface Condition After Harvest (ICNAH) 3Orchards floor maintained similar to a meadow
Date of Crop Emergence
(EMD, EMM, IYREM)
25/04 leaf-out, full canopy, leaf fall info from Steve Castagnoli, Hood River OR Extension
Date of Crop Maturity
(MAD, MAM, IYRMAT)
31/05
Date of Crop Harvest
(HAD, HAM, IYRHAR)
07/11
Maximum Dry Weight (WFMAX) 0.0Set to "0" Not used in simulation
SCS Curve Number (CN) 84, 79, 82Gleams Manual Table A.3, meadow; condition good (USDA, 1990)
Manning's N Value (MNGN) 0.040 RUSLE Project, A13OFOFN for orchards, no-till- Salem, OR (USDA, 2000)
USLE C Factor (USLEC) 0.005 - 0.034 RUSLE Project; A13OFOFN for orchards, no-till- Salem, OR (USDA, 2000)

Table 4.
PRZM 3.12 Cornelius Soil Parameters for Marion County Oregon - Apples
ParameterValue Verification Source
Total Soil Depth (CORED) 148 cm NRCS, National Soils Characterization Database (NRCS, 2001)
Number of Horizons (NHORIZ) 5 (4 Base with top split in two)
First, Second, Third, Fourth, and Fifth Soil Horizons (HORIZN = 1,2,3,4,5)
Horizon Thickness (THKNS)
  • 15 cm (HORIZN = 1,3)
  • 13 cm (HORIZN = 2)
  • 55 cm (HORIZN = 4)
  • 50 cm (HORIZN = 5)
NRCS, National Soils Characterization Database (NRCS, 2001) http://soils.usda.gov/survey/nscd/ Exit EPA Disclaimer
Bulk Density (BD)
  • 1.30 g cm-3 (HORIZN = 1)
  • 1.38 g cm-3 (HORIZN = 2)
  • 1.58 g cm-3 (HORIZN = 3)
  • 1.52 g cm-3 (HORIZN = 4)
  • 1.46 g cm-3 (HORIZN = 5)
Initial Water Content (THETO)
  • 0.329 cm3-H2O cm3-soil (HORIZN =1)
  • 0.338 cm3-H2O cm3-soil (HORIZN =2)
  • 0.340 cm3-H2O cm3-soil (HORIZN =3)
  • 0.358 cm3-H2O cm3-soil (HORIZN =4)
  • 0.202 cm3-H2O cm3-soil (HORIZN =5)
Compartment Thickness (DPN)
  • 0.1 cm (HORIZN = 1)
  • 1.0 cm (HORIZN = 2,3)
  • 5.0 cm (HORIZN = 4,5)
Field Capacity (THEFC)
  • 0.329 cm3-H2O cm3-soil (HORIZN =1)
  • 0.338 cm3-H2O cm3-soil (HORIZN =2)
  • 0.340 cm3-H2O cm3-soil (HORIZN =3)
  • 0.358 cm3-H2O cm3-soil (HORIZN =4)
  • 0.202 cm3-H2O cm3-soil (HORIZN =5)
Wilting Point (THEWP)
  • 0.099 cm3-H2O cm3-soil (HORIZN = 1)
  • 0.108 cm3-H2O cm3-soil (HORIZN = 2)
  • 0.110 cm3-H2O cm3-soil (HORIZN = 3)
  • 0.148 cm3-H2O cm3-soil (HORIZN = 4)
  • 0.142 cm3-H2O cm3-soil (HORIZN = 5)
Organic Carbon Content (OC)
  • 2.30% (HORIZN = 1)
  • 1.11% (HORIZN = 2)
  • 0.21% (HORIZN = 3)
  • 0.145% (HORIZN = 4)
  • 0.07% (HORIZN = 5)

EPA. 1985. Field Agricultural Runoff Monitoring (FARM) Manual, (EPA/600/3-85/043) Environmental Research Laboratory, U.S. Environmental Protection Agency, Athens, GA.

EPA. 1998. Carsel, R.F., J.C. Imhoff, P.R. Hummel, J.M. Cheplick, and A.S. Donigian, Jr. PRZM-3, A Model for Predicting Pesticide and Nitrogen Fate in the Crop Root and Unsaturated Soil Zones: Users Manual for Release 3.0. National Exposure Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Athens, GA.

EPA. 1999. Jones, R.D., J. Breithaupt, J. Carleton, L. Libelo, J. Lin, R. Matzner, and R. Parker. Guidance for Use of the Index Reservoir in Drinking Water Exposure Assessments. Environmental Fate and Effects Division, Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington. D.C.

EPA. 2001. Abel, S.A. Procedure for Conducting Quality Assurance and Quality Control of Existing and New PRZM Field and Orchard Crop Standard Scenarios. Environmental Fate and Effects Division, Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C.

Haan, C.T. and B.J. Barfield. 1978. Hydrology and Sedimentology of Surface Mined Lands. Office of Continuing Education and Extension, College of Engineering, University of Kentucky, Lexington, Kentucky 40506. pp. 286.

USDA. 1990. Davis, F.M., R.A. Leonard, W.G. Knisel. GLEAMS User Manual, Version 1.8.55. USDA-ARS Southeast Watershed Research Laboratory, Tifton GA. SEWRL-030190FMD.

USDA. 2000. Revised Universal Soil Loss Equation (RUSLE) EPA Pesticide Project. U.S. Department of Agriculture, National Resources Conservation Service (NRCS) and Agricultural Research Service (ARS).

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