The field used to represent alfalfa production in Pennsylvania is located in York County in south-central Pennsylvania. According to the 1997 Census of Agriculture, Pennsylvania is ranked 15th overall in the production of alfalfa in the U.S. Alfalfa is a perennial crop, grown on a variety of soils, planted early in the year and maintained under continuous cultivation on a 3- to 5-year cycle at which time a new crop is planted. Planting depths range from 0.25 to 1.0 inches, depending on soil texture, on level seed beds. Row spacing is approximately 30 inches; alfalfa is not irrigated in Pennsylvania. Cuttings range from 2 to 4 per year. Most farmers take the last cutting of the season in September. Alfalfa prefers well-drained soils with a pH near neutral (pH 6.7-6.9). The soil selected to simulate the field is a benchmark soil, Glenville silt loam. Glenville silt loam, is a fine-loamy, mixed, active, mesic, Aquic Fragiudults. These soils are in general crop production, but mostly grain, hay and pasture. Glenville silt loam is a very deep, moderately well drained or somewhat poorly drained, medium to slowly permeable soil with medium to slow runoff and consists of a fragipan at approximately 2 feet. In the fragipan, permeability is slow to moderately slow. These soils formed in residuum weathered from mica acid schist and crystalline rock containing mica. They are found on nearly level to strongly sloping upland flats, footslopes, or near the heads of drainageways. Slopes range from 0 to 15 percent. These soils are extensive in the mid-Atlantic Piedmont. Glenville silt loam is a Hydrologic Group C soil.
|Starting Date||January 1, 1948||Meteorological File - Allentown, PA (W14737)|
|Ending Date||December 31, 1983||Meteorological File - Allentown, PA (W14737)|
|Pan Evaporation Factor (PFAC)||0.76||PRZM Manual Figure 5.1 (EPA, 1998)|
|Snowmelt Factor (SFAC)||0.3 cm C- 1||PRZM Manual Table 5.1 (EPA, 1998)|
|Minimum Depth of Evaporation (ANETD)||12.5 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)||0.123||Haan and Barfield, 1978.|
|USLE P Factor (USLEP)||0.60||Leon Restler, Ag. Extension Agent, Lancaster Co. (717) 394-6851 8/14/01)|
|Field Area (AFIELD)||172 ha||Area of Shipman Reservoir watershed (EPA, 1999)|
|NRCS Hyetograph (IREG)||3||PRZM Manual Figure 5.12 (EPA, 1998)|
|Slope (SLP)||12%||Leon Restler, Ag. Extension Agent, Lancaster Co. (717) 394-6851 8/14/01)|
|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 fallow 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. Allentown, PA (W14737)|
|Maximum rainfall interception storage of crop (CINTCP)||0.25||PRZM, Table 5.4 (EPA, 1998)|
|Maximum Active Root Depth (AMXDR)||120 cm||Leon Restler, Ag. Extension Agent, Lancaster Co. (717) 394-6851 8/14/01)|
|Maximum Canopy Coverage (COVMAX)||100||Leon Restler, Ag. Extension Agent, Lancaster Co. (717) 394-6851 8/14/01)|
|Soil Surface Condition After Harvest (ICNAH)||3||Set to residue for winter months after last harvest during multi-year growth and during winter of last years of growth.|
|Date of Crop Emergence
(EMD, EMM, IYREM)
|15/04||Leon Restler, Ag. Extension Agent, Lancaster Co. (717) 394-6851 8/14/01)|
|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)||87, 83, 86||Gleams Manual Table A.3, pasture/range, non-CNT, poor condition (USDA, 1990)|
|Manning's N Value (MNGN)||0.110||RUSLE Project, SB5HL HLC; Hay, legume, conventional till, York (USDA, 2000)|
|USLE C Factor (USLEC)||0.001 - 0.017||RUSLE Project; SB5HLHLC; Hay, legume, conventional till, York (USDA, 2000)|
|Total Soil Depth (CORED)||120 cm||NRCS, National Soils Characterization Database (NRCS, 2001)|
|Number of Horizons (NHORIZ)||3 (Top horizon split in two)|
|First, Second, and Third Soil Horizons (HORIZN = 1,2,3)|
|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).