OREGON SWEET CORN
The field used to represent sweet corn production in Oregon is located in Marion County, in the Willamette Valley. According to the 1997 Census of Agriculture, Oregon is ranked 4th in sweet corn for processing. Only a small percent is produced for the fresh market. Marion County farmers harvest the most acres in the state. The crop is generally planted in the early Spring (May) and harvested beginning in September. Continuous sweet corn is practice is much of the region, however, rotation with other crops is practiced as well. Planting depth and row spacing (generally 30 inches) follows general practices for the U.S. Conventional tillage dominates, followed by conservation tillage and no-tillage. The crop is rarely grown under irrigation. The soil selected to simulate the field is a benchmark soil, Woodburn silt loam. Woodburn silt loam, is a fine-silty mixed, superactive, mesic Aquultic Agrixerolls. The series is used to produce berries, orchards, cannery crops, grain, hay, and pasture. Woodburn silt loam is a very deep, moderately well drained, slowly permeable soil with slow to medium runoff. These soils formed in stratified glacio lacustrine deposits of the Pleistocene age. They are found on nearly level to gently sloping broad valley terraces at elevations of 150 to 400 feet above mean sea level on slopes of 0 to 55 percent. The series is extensive in the Willamette Valley. Woodburn silt loam is a Hydrologic Group C soil.
|Starting Date||January 1, 1948||Meteorological File - Salem, OR (W24232)|
|Ending Date||December 31, 1983||Meteorological File - Salem, OR (W24232)|
|Pan Evaporation Factor (PFAC)||0.74||PRZM Manual Figure 5.1 (EPA, 1998)|
|Snowmelt Factor (SFAC)||0.15 cm C- 1||PRZM Manual Table 5.1 (EPA, 1998)|
|Minimum Depth of Evaporation (ANETD)||15.0 cm||PRZM Manual Figure 5.2 (EPA, 1998)|
|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)||1.34||Haan and Barfield, 1978|
|USLE P Factor (USLEP)||1.0||Set according to guidance (EPA, 2001)|
|Field Area (AFIELD)||172 ha||Area of Shipman Reservoir watershed (EPA, 1999)|
|NRCS Hyetograph (IREG)||2||PRZM Manual Figure 5.12 (EPA, 1998)|
|Slope (SLP)||6%||Value set to maximum for crop (EPA, 2001)|
|Hydraulic Length (HL)||600 m||Shipman Reservoir (EPA, 1999)|
* EI = 100 ft-tons * in/ acre*hr
|Initial Crop (INICRP)||1||Set to one for all crops (EPA, 2001)|
|Initial Surface Condition (ISCOND)||1||Set to residue prior to new crop planting|
|Number of Different Crops (NDC)||1||Set to crops in simulation - generally one|
|Number of Cropping Periods (NCPDS)||36||Set to weather data. Salem, OR (W24232)|
|Maximum rainfall interception storage of crop (CINTCP)||0.25||PRZM Manual, Table 5.4 (EPA, 1998)|
|Maximum Active Root Depth (AMXDR)||90 cm||PRZM Input Collator, PIC (Burns, 1992); PRZM Table 5.9 (EPA, 1998)|
|Maximum Canopy Coverage (COVMAX)||100||Set to default for row crops (EPA, 2001)|
|Soil Surface Condition After Harvest (ICNAH)||1||Crop profile says some are moving to cover crops, grass, instead of wheat- most conservative scenario chosen|
|Date of Crop Emergence
(EMD, EMM, IYREM)
|10/05||Dan McGrath, OSU extension agent|
|Date of Crop Maturity
(MAD, MAM, IYRMAT)
|Date of Crop Harvest
(HAD, HAM, IYRHAR)
|Maximum Dry Weight (WFMAX)||0.0||Set to "0" Not used in simulation|
|SCS Curve Number (CN)||91, 85, 87||Gleams Manual Table A.3,SR/fallow and SR/Row crops from table H-4 (USDA, 1990)|
|Manning's N Value (MNGN)||0.014||RUSLE Project, A13CSWWC, Corn, Silage, Conventional Tillage, Salem, OR (USDA, 2000)|
|USLE C Factor (USLEC)||0.099 - 0.528||RUSLE Project; A13CSWWC, Corn, Silage, Conventional Tillage, Salem, OR (USDA, 2000)|
|Total Soil Depth (CORED)||203 cm||NRCS, National Soils Characterization Database (NRCS, 2001)|
|Number of Horizons (NHORIZ)||7 (Top horizon split in two)|
|First, Second, Third, Fourth, Fifth, Sixth, and Seventh Soil Horizons (HORIZN = 1,2,3,4,5,6,7)|
|Horizon Thickness (THKNS)||
||NRCS, National Soils Characterization Database (NRCS, 2001) http://soils.usda.gov/survey/nscd/|
|Bulk Density (BD)||
|Initial Water Content (THETO)||
|Compartment Thickness (DPN)||
|Field Capacity (THEFC)||
|Wilting Point (THEWP)||
|Organic Carbon Content (OC)|
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).