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CALIFORNIA GRAPES (Northern and Southern)
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The field used to represent grape production in California is located in Southern San Joaquin Valley. According to the 1997 Census of Agriculture, California is the major producer of table, wine, and raisin grapes with 85 percent of California's production in the San Joaquin Valley and the bulk of the remainder in the Coachella Valley. Grapes need at least 3 ft of well drained soil, and are typically grown on sandy or sandy loam soils. Vine rows are usually kept weed free, but there is some growth in the winter. Surface soil around the vine row is usually sealed, but some plants can grow between vine rows. The soil between rows is usually disked. Row spacing varies depending on the terrain. Canopies between rows tend to be much less than 100 percent, while the canopy along the rows is 100 percent. Irrigation is mainly by drip irrigation, but some vineyards continue to use sprinkler systems. The soil selected to simulate the field is a benchmark soil, San Joaquin loam. San Joaquin loam, is a fine, mixed, active, thermic Abruptic Durixeralfs. These soils are often used for vineyards, fruit and nut production under irrigation. San Joaquin loam is a moderately deep, well and moderately well drained, medium to very high runoff soil that formed in alluvium mainly from granite sources. The soil also consists of a duripan. The San Joaquin loam has very slow permeability above the duripan and very slow permeability within the duripan. Some areas are subject to flooding. These soil are generally found on undulating terraces at elevations from 50 to 500 feet above mean sea level and have slopes of 0 to 9 percent. The soil is extensive in MLRA 17 along the Eastern slopes of the Sacramento and San Joaquin Valleys. San Joaquin loam is a Hydrologic Group C soil.
| Parameter | Value | Source |
|---|---|---|
| Starting Date | January 1, 1948 | Meteorological File - Southern: Bakersfield, CA (W23155) and Northern: Sacramento, CA (W23232) |
| Ending Date | December 31, 1983 | Meteorological File - Southern: Bakersfield, CA (W23155) and Northern: Sacramento, CA (W23232) |
| Pan Evaporation Factor (PFAC) | 0.7 | PRZM Manual Figure 5.1 (EPA, 1998) |
| Snowmelt Factor (SFAC) | 0.55 cm C- 1 | PRZM Manual Table 5.1 (EPA, 1998) |
| Minimum Depth of Evaporation (ANETD) | 17.0 cm | PRZM Manual Figure 5.2 (EPA, 1998) |
| Parameter | Value | Source |
|---|---|---|
| Method to Calculate Erosion (ERFLAG) | 4 (MUSS) | PRZM Manual (EPA, 1998) |
| USLE K Factor (USLEK) | 0.28 tons EI-1* | NRI - Average value listed for the soil series San Joaquin |
| USLE LS Factor (USLELS) | 0.2 | NRI - Average value listed for the soil series San Joaquin |
| USLE P Factor (USLEP) | 1.0 | NRI - Average value listed for the soil series San Joaquin |
| Field Area (AFIELD) | 172 ha | Area of Shipman Reservoir watershed (EPA, 1999) |
| NRCS Hyetograph (IREG) | 1 | PRZM Manual Figure 5.12 (EPA, 1998); based on crops grown on Eastern side of slopes. |
| Slope (SLP) | 2% | Paul Verdegaal San Joaquin County Cooperative Extension 209-468-9494 |
| Hydraulic Length (HL) | 600 m | Shipman Reservoir (EPA, 1999) |
| Irrigation Flag (IRFLAG) | 2 (cropping period only) | Based on recommendations from farm advisors for general flooding for crop irrigation |
| Irrigation Type (IRTYP) | 1 (Flood) | Based on recommendations from farm advisors for general flooding for crop irrigation |
| Leaching Factor (FLEACH) | 0.1 | Estimated |
| Fraction of Water Capacity when Irrigation is Applied (PCDEPL) | 0.55 | Based on recommendations from farm advisors for general flooding for crop irrigation |
| Maximum Rate at which Irrigation is Applied (RATEAP) | 0.4 cm hr-1 | PRZM Manual, Table 5.33 (EPA, 1998) |
* EI = 100 ft-tons * in/ acre*hr
| Parameter | Value | Source |
|---|---|---|
| Initial Crop (INICRP) | 1 | Set to one for all crops (EPA, 2001) |
| Initial Surface Condition (ISCOND) | 3 | Paul Verdegaal San Joaquin County Cooperative Extension 209-468-9494 |
| 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 - Bakersfield, CA (W23155) or Sacramento, CA (W23232) |
| Maximum rainfall interception storage of crop (CINTCP) | 0.25 | Maximum recommended value for grass (EPA, 2001) |
| Maximum Active Root Depth (AMXDR) | 100 cm | Paul Verdegaal San Joaquin County Cooperative Extension 209-468-9494 |
| Maximum Canopy Coverage (COVMAX) | 70 | Paul Verdegaal San Joaquin County Cooperative Extension 209-468-9494 |
| Soil Surface Condition After Harvest (ICNAH) | 3 | Paul Verdegaal San Joaquin County Cooperative Extension 209-468-9494 |
| Date of Crop Emergence (EMD, EMM, IYREM) |
01/02 | Paul Verdegaal San Joaquin County Cooperative Extension 209-468-9494 |
| Date of Crop Maturity (MAD, MAM, IYRMAT) |
15/08 | Paul Verdegaal San Joaquin County Cooperative Extension 209-468-9494 |
| Date of Crop Harvest (HAD, HAM, IYRHAR) |
31/08 | Paul Verdegaal San Joaquin County Cooperative Extension 209-468-9494 |
| Maximum Dry Weight (WFMAX) | 0.0 | Set to "0" Not used in simulation |
| SCS Curve Number (CN) | 84, 79, 82 | Gleams Manual Table A.3, Meadows, no fallow conditions (USDA, 1990) |
| Manning's N Value (MNGN) | 0.023 | RUSLE Project; C21GBGBC for grapes, Sacramento, bare ground (USDA, 2000) |
| USLE C Factor (USLEC) | 0.274 - 0.517 | RUSLE Project; Variable with date, C21GBGBC for grapes, Sacramento, bare ground (USDA, 2000) |
| Parameter | Value | Verification Source |
|---|---|---|
| Total Soil Depth (CORED) | 340 cm | NRCS, National Soils Characterization Database (NRCS, 2001) |
| Number of Horizons (NHORIZ) | 2 (Base horizons) | |
| First and Second Soil Horizons (HORIZN = 1,2) | ||
| Horizon Thickness (THKNS) |
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NRCS, National Soils Characterization Database (NRCS, 2001) http://soils.usda.gov/survey/nscd/
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| Bulk Density (BD) |
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| Initial Water Content (THETO) |
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| Compartment Thickness (DPN) |
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| Field Capacity (THEFC) |
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| Wilting Point (THEWP) |
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| Organic Carbon Content (OC) |
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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).