Jump to main content.



The field used to represent apple production in North Carolina is located in Henderson County, in Western North Carolina. According to the 1997 Census of Agriculture, North Carolina is among the major producers of apples (7th to 8th overall) in the U.S., and is one of the southern most production areas. There are four primary apple production areas in western North Carolina, all long-term perennial regions, grown on a variety of soils, in different climate regions. Henderson County produces between 60 to 70 percent of the apple crop. 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 benchmark soil, Hayesville loam. Hayesville loam, is a fine, kaolinitic, mesic, Typic Kanhapludults. About one-half of these soils are under cultivation in corn, small grains, pasture, hayland, tobacco, vegetables, and Christmas trees. Hayesville loam is a very deep, well drained, moderately rapid permeable soil with slow to high runoff depending on slope. These soils formed in residuum weathered from igneous and high-grade metamorphic rocks. They are found on gently sloping to very steep ridges and side slopes of the Southern Appalachian Mountains. They are located at elevations from 100 to 4000 feet above mean sea level on slopes of 2 to 60. The series is of large extent in the mountain areas of lower South. Hayesville loam is a Hydrologic Group C soil.

Table 1.
PRZM 3.12 Climate and Time Parameters for Henderson County North Carolina - Apples
Starting Date January 1, 1948Meteorological File - Bristol, TN (W13877)
Ending Date December 31, 1983Meteorological File - Bristol, TN (W13877)
Pan Evaporation Factor (PFAC) 0.76PRZM Manual Figure 5.1 (EPA, 1998)
Snowmelt Factor (SFAC) 0.2 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 Henderson County North Carolina - Apples
Method to Calculate Erosion (ERFLAG) 4 (MUSS)PRZM Manual (EPA, 1998)
USLE K Factor (USLEK) 0.2 tons EI-1* GLEAMS Table of Representative Soils (USDA, 1990)
USLE LS Factor (USLELS) 3.04GLEAMS Table of Representative Soils (USDA, 1990)
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) 3PRZM 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 Henderson County North Carolina - Apples
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. Bristol, TN (W13877)
Maximum rainfall interception storage of crop (CINTCP) 0.25Set to default for orchards (EPA, 2001)
Maximum Active Root Depth (AMXDR) 150 cmSet to maximum soil depth. Roots may grow to 20 feet.
Maximum Canopy Coverage (COVMAX) 90 http://caf.wvu.edu/kearneysville/fruitloop.html ; Exit EPA Disclaimer
Ross Byers, Horticultural Specialist VPI - canopy somewhat open between rows; 90% reasonable upper end estimate.
Soil Surface Condition After Harvest (ICNAH) 3Orchards floor maintained similar to a meadow
Date of Crop Emergence
07/04 Personal communication w/ Ross Byers, VA Tech Fruit Horticulturalist (540) 869-2560 x19"Emergence based on leaf emergence, Maturation based on canopy maturity, Harvest based on average leaf fall. Dates based on central VA and modified by: 1 day added for every 100 miles north or 100 feet higher elevation or 1day subtracted for every 100 miles south or 100 feet lower elevation.
Date of Crop Maturity
Date of Crop Harvest
Maximum Dry Weight (WFMAX) 0.0Set to "0" Not used in simulation
SCS Curve Number (CN) 84, 79, 82 Gleams Manual Table A.3, meadow; condition good (USDA, 1990)
Manning's N Value (MNGN) 0.023 RUSLE Project, NB0OBOBC; Orchard bare ground; conventional tillage; Asheville, NC (USDA, 2000)
USLE C Factor (USLEC) 0.008 - 0.057 RUSLE Project; NB0OBOBC; Orchard bare ground; conventional tillage; Asheville, NC (USDA, 2000)

Table 4.
PRZM 3.12 Hayesville Soil Parameters for Henderson County North Carolina - Apples
ParameterValue Verification Source
Total Soil Depth (CORED) 150 cm NRCS, National Soils Characterization Database (NRCS, 2001)
Number of Horizons (NHORIZ) 4 (3 Base, Top horizon split in two)
First, Second, Third, and Fourth Soil Horizons (HORIZN = 1,2,3,4)
Horizon Thickness (THKNS)
  • 10 cm (HORIZN = 1)
  • 6 cm (HORIZN = 2)
  • 84 cm (HORIZN = 3)
  • 50 cm (HORIZN = 4)
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 = 1,2,3,4)
Initial Water Content (THETO)
  • 0.392 cm3-H2O cm3-soil (HORIZN =1,2)
  • 0.475 cm3-H2O cm3-soil (HORIZN =3)
  • 0.259 cm3-H2O cm3-soil (HORIZN =4)
Compartment Thickness (DPN)
  • 0.1 cm (HORIZN = 1)
  • 2 cm (HORIZN = 2,3)
  • 5.0 cm (HORIZN = 4)
Field Capacity (THEFC)
  • 0.392 cm3-H2O cm3-soil (HORIZN = 1,2)
  • 0.475cm3-H2O cm3-soil (HORIZN = 3)
  • 0.259 cm3-H2O cm3-soil (HORIZN = 4)
Wilting Point (THEWP)
  • 0.192 cm3-H2O cm3-soil (HORIZN = 1,2)
  • 0.275 cm3-H2O cm3-soil (HORIZN = 3)
  • 0.109 cm3-H2O cm3-soil (HORIZN = 4)
Organic Carbon Content (OC)
  • 0.58% (HORIZN = 1,2)
  • 0.116 (HORIZN = 3)
  • 0.058% (HORIZN = 4)

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.

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).

Top of page

Publications | Glossary | A-Z Index | Jobs

Local Navigation

Jump to main content.