The field used to represent peach production in Georgia is located in Peach County in Southwest Georgia (MLRA133) and the weather station representing the orchard is in MLRA 137 and located in Macon, GA. Peaches are grown throughout the state, Peach County represents the highest producing county in Georgia and the 7th highest producing county in the U.S. Tree row spacing is generally 15 to 20 feet and within row spacing varies with the variety and maintenance size of the tree from as little as 8 feet to 20 feet. Tree heights are maintained from 8 feet to as much as 20 or more feet. Tree size and density is carefully maintained to optimize fruit production and pesticide and growth regulator applications. Flower buds begin to swell in late Winter to early Spring in the South as heat accumulates followed closely by bud bloom. At the time of flowering the fruiting stage commences and continues through harvest. For high yields of quality fruit, proper soil and site management, among other factors are necessary. Soil characteristics have a significant influences on tree development, fruit bearing capacity, and tree life. Of these, soil texture and drainage are among the most important for peach tree health. Peach trees do best in moderately to well drained soils of a sandy to silt loam texture. Trees do not tolerate wet soils for prolonged periods of time (days to weeks) during the growing period. The soil selected to simulate the field is a Greenville fine sandy loam in the Greenville-Faceville-Orangeburg Association. Grenville fine sandy loam is a fine, kaolinitic, thermic Rhodic Kandiudults. These soils are often used for peach, truck crop and grain production. Greenville fine sandy loam is a very deep, well drained, medium runoff, moderately permeable soil that formed in clayey marine sediments on the Coastal Plain. These soil are generally found on uplands and have slopes generally less than 8 percent, but may range up to 18 percent. The soil is extensive in the Coastal Plains of the South. Greenville fine sandy loam is a Hydrologic Group B soil.
|Starting Date||January 1, 1948||Meteorological File - Macon, GA (W93805)|
|Ending Date||December 31, 1983||Meteorological File - Macon, GA (W93805)|
|Pan Evaporation Factor (PFAC)||0.75||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)||25.0 cm||PRZM Manual Figure 5.2 (EPA, 1998)|
|Method to Calculate Erosion (ERFLAG)||4 (MUSS)||PRZM Manual (EPA, 1998)|
|USLE K Factor (USLEK)||0.35 tons EI-1*||FARM Manual (EPA, 1985)|
|USLE LS Factor (USLELS)||3.63||Haan and Barfield, 1979|
|USLE P Factor (USLEP)||1.0||PRZM Manual, table 5.6 (EPA, 1998)|
|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%||Mid-point of soil series range (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)||3||Residues remain in field between tree rows, area under trees, approximately 3x3 feet, maintained residue free|
|Number of Different Crops (NDC)||1||Set to crops in simulation - generally one|
|Number of Cropping Periods (NCPDS)||36||Set to weather data. Meteorological File - Macon, GA (W93805)|
|Maximum rainfall Interception storage of crop (CINTCP)||0.25||PIC; confirmed using Table 5.4 from PRZM Manual (Burns, 1992 and EPA, 1985)|
|Maximum Active Root Depth (AMXDR)||150 cm||Set to soil horizon depth; roots may grow in excess of 5 feet deep. http://pods.dasnr.okstate.edu/docushare/dsweb/HomePage|
|Maximum Canopy Coverage (COVMAX)||60||Based on estimates from aerial photography|
|Soil Surface Condition After Harvest (ICNAH)||3||Residues remain in field between tree rows, area under trees, approximately 3x3 feet, maintained residue free|
|Date of Crop Emergence
(EMD, EMM, IYREM)
|01/03||Emergence set to flower bud, Mark Collier, Extension Agent, Peach County, GA|
|Date of Crop Maturity
(MAD, MAM, IYRMAT)
|15/05||Maturation set to beginning of harvest, Mark Collier, Extension Agent, Peach County, GA|
|Date of Crop Harvest
(HAD, HAM, IYRHAR)
|31/08||Harvest set to last days of harvest, Mark Collier, Extension Agent, Peach County, GA|
|Maximum Dry Weight (WFMAX)||0.0||Set to "0" Not used in simulation|
|SCS Curve Number (CN)||78, 67, 74||Gleams Manual Table A.3,Meadow, conditions good for Hydrologic Soil B; Peach trees do not tolerate soils less than moderately drained. (USDA, 1990)|
|Manning's N Value (MNGN)||0.07||RUSLE EPA Pesticide Project; Tb7WWSBC; Savannah, GA; Winter Wheat, Cover Code 3 (residues), Conventional Tillage (USDA, 2000)|
|USLE C Factor (USLEC)||0.021 - 0.259||RUSLE EPA Pesticide Project; Tb7WWSBC; Savannah, GA; Winter Wheat, Cover Code 3 (residues), Conventional Tillage (USDA, 2000)|
|Total Soil Depth (CORED)||150 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)||
Burns. 1992. Burns, L.A., (Coordinator), B.W. Allen, Jr., M.C. Barber, S.L. Bird, J.M. Cheplick, M.J. Fendley, D.R. Hartel, C.A. Kittner, F.L. Mayer, Jr., L.A. Suarez, and S.E. Wooten. Pesticide and Industrial Chemical Risk Analysis and Hazard Assessment, Version 3.0. (PIRANHA) Environmental Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Athens, GA. 1992.
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).