**CALIFORNIA AVOCADOS**

Avocados are grown on approximately 60,000 acres, primarily in southern
and central California, typically in regions tempered by coastal
climates. Most of the avocado acreage lies between San Luis Obispo and
San Diego. Avocados are produced in 15 counties but five coastal
counties account for essentially all of the state\'s production. Based
on 2002 USDA census data, San Diego, Santa Barbara, and Ventura Counties
are the top producing counties, accounting for approximately 80% of the
total avocado acreage in California (USDA, 2002). San Diego County is
the leading county, producing nearly 47% of California market value for
avocados (USDA, 1999a), accounting for 39% of the state\'s avocado
producing acreage (USDA, 2002). Other counties with significant
production are Riverside (14%) and Orange (3%) counties. California
produces 95% of the avocados grown in the United States and 10% of the
world\'s production. From 1990 to 1998, California\'s average production
was 323 million pounds, with typical fluctuations of 5% (USDA, 1999a)
This crop requires relatively few chemicals to control insect pests.
Beneficial insects are used as part of an Integrated Pest Management
(IPM) approach in which harsh chemicals are avoided to maintain this
balance.

Several varieties of avocados are harvested in California including,
Haas, Lamb Haas, Bacon, Zutano, Fuerte, Pinkerton and Gwen. The Haas
variety is the predominant tree accounting for roughly 90% of the total
production. Due to California\'s unique coastal micro-climate, avocados
are harvested year round with a typical tree yielding 60 lbs of fruit
per year. The official avocado crop year runs from November 1 through
October 31. Avocado fruit can be held successfully after harvest in cold
storage for approximately 2 to 4 weeks. The size and oil levels of the
harvested fruit, in part, determine the grade of the harvest.

Avocados are typically grown in well-drained, fine or course sandy loam
soils. Micro sprinkler and drip irrigation systems typically are used to
deliver water to the grove floor. Avocado roots are relatively shallow,
so deep watering is unnecessary. There are over two-dozen avocado
bearing soils in San Diego, Santa Barbara, and Ventura Counties alone
(USDA, 2006). Approximately 63% of avocado bearing soils in these
counties are in drainage groups C and D. Of these, the Cieneba series is
the most common avocado bearing soil with moderate expected yields under
irrigation (Table 5). The Cieneba series accounts for approximately 37%
of avocado bearing soil acreage (USDA, 2006). Cieneba soils are thermic,
shallow Typic Xerorthents located on uplands with slopes of 9 to 85
percent (USDA, 1999b). Location and metfile selections are often the
most important developments affecting scenario vulnerability and
protectiveness. Because this scenario is intended to represent avocado
production along the southern coastal area of California, the metfile
closest to the center of the primary avocado producing county (San
Diego) was chosen. The Cieneba soil series was selected for this
scenario because it is both representative of avocado bearing soils
(Oster, 2006), is predominant in San Diego County as well as central and
southern California, represents the majority (44%) of avocado soils in
drainage, the fourth most erosive soil type, and is among the steeper
sloped avocado bearing soils (Table 5).

Cieneba is a Hydrologic Group C soil, which represents the majority
(44%) of these soils in drainage. Cieneba soils have a USLE K factor of
ranging from 0.24-0.32; approximately 82% of avocado bearing soils have
a USLE K factor between 0.24 and 0.32 (Table 5). Approximately 10% of
avocado bearing soils have a pH lower than Cieneba soils (5.8 - 6.5),
although soil pH is not currently a PRZM input parameter and is not
expected to often affect chemical fate in the acidic range. Based on the
official soil series description, Ceineba soils have an A horizon from 0
to 10 inches (0-25 cm) deep and a C horizon from 10 to over 30 inches
(25-76 cm) deep, however the C horizon is primarily weathered granitic
material with remnant rock structure. (USDA, 2006). Cieneba coarse sandy
loam was used to parameterize this scenario (USDA 2005).

The Met station chosen was the San Diego station (23188.dvf) located at
32º 44' N, 117º 10' W and at an elevation of approximately 4 meters
above sea level. This station receives an average of approximately 25.2
cm of rainfall annually. The station is the closest available station to
this scenario with data necessary for PRZM.

+-----------------+----------+-----------------------------------------+
| **Table 1. PRZM |          |                                         |
| 3.12 Climate    |          |                                         |
| and Time        |          |                                         |
| Parameters for  |          |                                         |
| San Diego,      |          |                                         |
| California --   |          |                                         |
| Avocado.**      |          |                                         |
+-----------------+----------+-----------------------------------------+
| **Parameter**   | *        | **Source/Comments**                     |
|                 | *Value** |                                         |
+-----------------+----------+-----------------------------------------+
| Starting Date   | Jan. 1,  | Meteorological File from San Diego      |
|                 | 1961     | County, (W 23188)                       |
+-----------------+----------+-----------------------------------------+
| Ending Date     | Dec. 31, | Meteorological File from San Diego      |
|                 | 1990     | County, (W 23188)                       |
+-----------------+----------+-----------------------------------------+
| Pan Evaporation | 0.70     | PRZM Manual Figure 5.1. Value           |
| Factor (PFAC)   |          | represents San Diego region.            |
+-----------------+----------+-----------------------------------------+
| Snowmelt Factor | 0        | In areas where climatology prevents     |
| (SFAC)          |          | snow fall, SFAC should be set to 0.0 -  |
|                 |          | PRZM Manual (EPA 1998)                  |
+-----------------+----------+-----------------------------------------+
| Minimum Depth   | 32.5 cm  | PRZM Manual (EPA 1998) Average of 30-35 |
| of              |          | cm                                      |
|                 |          |                                         |
| Evaporation     |          |                                         |
| (ANETD)         |          |                                         |
+-----------------+----------+-----------------------------------------+

+-----------------+----------+-----------------------------------------+
| **Table 2. PRZM |          |                                         |
| 3.12 Erosion    |          |                                         |
| and Landscape   |          |                                         |
| Parameters for  |          |                                         |
| San Diego,      |          |                                         |
| California --   |          |                                         |
| Avocado.**      |          |                                         |
+=================+==========+=========================================+
| **Parameter**   | *        | **Source/Comments**                     |
|                 | *Value** |                                         |
+-----------------+----------+-----------------------------------------+
| Method to       | 4 (MUSS) | PRZM Manual (EPA, 1998)                 |
| Calculate       |          |                                         |
| Erosion         |          |                                         |
| (ERFLAG)        |          |                                         |
+-----------------+----------+-----------------------------------------+
| USLE K Factor   | 0.24     | USDA NRCS Soil Data Mart                |
| (USLEK)         |          | (http://soildatamart.nrcs.usda.gov/)    |
+-----------------+----------+-----------------------------------------+
| USLE LS Factor  | 3.63     | PRZM Manual (EPA, 1998)                 |
| (USLELS)        |          |                                         |
|                 |          | LS value for 12% slope and 400' slope   |
|                 |          | length; LS equation (Haan and Barfield, |
|                 |          | 1978)                                   |
+-----------------+----------+-----------------------------------------+
| USLE P Factor   | 1.0      | Set to 1 for orchards (EPA, 2004)       |
| (USLEP)         |          |                                         |
+-----------------+----------+-----------------------------------------+
| Field Area      | 172 ha   | Area of Shipman Reservoir watershed     |
| (AFIELD)        |          | (EPA, 1999)                             |
+-----------------+----------+-----------------------------------------+
| NRCS Hyetograph | 1        | PRZM Manual Figure 5.12 (EPA, 1998)     |
| (IREG)          |          |                                         |
|                 |          | Type I, IREG=1                          |
+-----------------+----------+-----------------------------------------+
| Slope (SLP)     | 12 %     | Slopes for Cieneba coarse sandy loam    |
|                 |          | exceed 12%. Set to 12% as per PRZM      |
|                 |          | scenario guidance (EPA, 2004). Some     |
|                 |          | data indicate slopes as high as 16%     |
|                 |          | (Oster and Arpaia 2006)                 |
+-----------------+----------+-----------------------------------------+
| Hydraulic       | 600 m    | Shipman Reservoir (EPA, 1999)           |
| Length (HL)     |          |                                         |
+-----------------+----------+-----------------------------------------+
| Irrigation Flag | 1        | Year round irrigation. EPA, 2005        |
| (IRFLAG)        |          |                                         |
+-----------------+----------+-----------------------------------------+
| Number range    | 4 (drip) | Irrigation Guidance for developing PRZM |
| CH              |          | Scenarios, Table 3; (EPA 2005).         |
| APTERIrrigation |          |                                         |
| Type (IRTYP)    |          |                                         |
+-----------------+----------+-----------------------------------------+
| Leaching Factor | 0.0      | Set to 0 as per Irrigation Guidance for |
| (FLEACH)        |          | developing PRZM Scenarios, Table 3;     |
|                 |          | (June 15, 2005).                        |
+-----------------+----------+-----------------------------------------+
| Fraction of     | 0.5      | Set to default as per Irrigation        |
| Water Capacity  |          | Guidance for developing PRZM Scenarios, |
| when Irrigation |          | Table 3; (EPA 2005).                    |
| is Applied      |          |                                         |
| (PCDEPL)        |          |                                         |
+-----------------+----------+-----------------------------------------+
| Maximum Rate at | 0.056 cm | Irrigation Guidance for developing PRZM |
| which           | hr^-1^   | Scenarios, Table 1; (June 15, 2005).    |
| Irrigation is   |          | For CN = 79 and f = 0                   |
| Applied         |          |                                         |
| (RATEAP)        |          |                                         |
+-----------------+----------+-----------------------------------------+
|                 |          |                                         |
+-----------------+----------+-----------------------------------------+

+-----------------+----------+-----------------------------------------+
| **Table 3. PRZM |          |                                         |
| 3.12 Crop       |          |                                         |
| Parameters for  |          |                                         |
| San Diego,      |          |                                         |
| California --   |          |                                         |
| Avocado.**      |          |                                         |
+=================+==========+=========================================+
| **Parameter**   | *        | **Source/Comments**                     |
|                 | *Value** |                                         |
+-----------------+----------+-----------------------------------------+
| Initial Crop    | 1        | Set to one for all crops (EPA, 2004).   |
| (INICRP)        |          |                                         |
+-----------------+----------+-----------------------------------------+
| Initial Surface | 3        | Orchard residues are left behind        |
| Condition       |          | between rows, under trees are cleared   |
|                 |          | to reduce disease. Consistent with the  |
| (ISCOND)        |          | FL avocado scenario and other orchard   |
|                 |          | type scenarios.                         |
+-----------------+----------+-----------------------------------------+
| Number of       | 1        | Set to number of crops in simulation.   |
| Different Crops |          |                                         |
| (NDC)           |          |                                         |
+-----------------+----------+-----------------------------------------+
| Number of       | 30       | Set to weather data in meteorological   |
| Cropping        |          | file: San Diego, CA (W23188).           |
| Periods (NCPDS) |          |                                         |
+-----------------+----------+-----------------------------------------+
| Maximum         | 0.25     | Recommended value for orchards (EPA,    |
| rainfall        |          | 2004).                                  |
| interception    |          |                                         |
| storage of crop |          |                                         |
| (CINTCP)        |          |                                         |
+-----------------+----------+-----------------------------------------+
| Maximum Active  | 25 cm    | Set to horizon depth. Most of the roots |
| Root Depth      |          | for Haas avocados grown in an orchard   |
| (AMXDR)         |          | with Cieneba soil type were located     |
|                 |          | above 15 cm (Oster and Arpaia 2006)     |
+-----------------+----------+-----------------------------------------+
| Maximum Canopy  | 70       | Taken from FL avocados scenario         |
| Coverage        |          |                                         |
| (COVMAX)        |          |                                         |
+-----------------+----------+-----------------------------------------+
| Soil Surface    | 3        | Plant residues are left behind.         |
| Condition After |          | Consistent with the FL avocado scenario |
| Harvest (ICNAH) |          | and other orchard type scenarios.       |
+-----------------+----------+-----------------------------------------+
| Date of Crop    | 01/01    | Values are set to keep E/T and canopy   |
| Emergence       |          | coverage terms working correctly for    |
|                 |          | this evergreen scenario.                |
| (EMD, EMM,      |          |                                         |
| IYREM)          |          |                                         |
+-----------------+----------+-----------------------------------------+
| Date of Crop    | 02/01    | Values are set to keep E/T and canopy   |
| Maturity        |          | coverage terms working correctly for    |
|                 |          | this evergreen scenario.                |
| (MAD, MAM,      |          |                                         |
| IYRMAT)         |          |                                         |
+-----------------+----------+-----------------------------------------+
| Date of Crop    | 31/12    | Values are set to keep E/T and canopy   |
| Harvest (HAD,   |          | coverage terms working correctly for    |
| HAM, IYRHAR)    |          | this evergreen scenario.                |
+-----------------+----------+-----------------------------------------+
| Maximum Dry     | 0.0      | Not used in scenario                    |
| Weight (WFMAX)  |          |                                         |
+-----------------+----------+-----------------------------------------+
| Maximum         | 914      | Avocado trees typically grow to 20-40   |
| CropHeight      |          | feet California Avocado Commission      |
| (HTMAX)         |          |                                         |
+-----------------+----------+-----------------------------------------+
| SCS Curve       | 84, 79,  | Gleams Manual Table H-4; meadows;       |
| Number (CN)     | 82       | hydrological group C (USDA, 1990)       |
+-----------------+----------+-----------------------------------------+
| Manning's N     | 0.023    | RUSLE Project; C25CFCFN for California  |
| Value (MNGN)    |          | citrus with full cover (USDA, 2000).    |
+-----------------+----------+-----------------------------------------+
| USLE C Factor   | 0.040 -  | RUSLE Project; C25CFCFN for California  |
| (USLEC)         | 0.062    | citrus with full cover (USDA, 2000).    |
+-----------------+----------+-----------------------------------------+

+---------------+-------------------+---------------------------------+
| **Table 4.    |                   |                                 |
| PRZM 3.12     |                   |                                 |
| Cieneba Soil  |                   |                                 |
| Parameters    |                   |                                 |
| for San       |                   |                                 |
| Diego,        |                   |                                 |
| California -- |                   |                                 |
| Avocado.**    |                   |                                 |
+---------------+-------------------+---------------------------------+
| **Parameter** | **Value**         | **Source/Comments**             |
+---------------+-------------------+---------------------------------+
| Total Soil    | 25 cm             | NRCS Soil Data Mart (SDM)       |
| Depth (CORED) |                   | (htt                            |
|               |                   | p://soildatamart.nrcs.usda.gov) |
+---------------+-------------------+---------------------------------+
| Number of     | 2                 | NRCS Soil Data Mart (SDM)       |
| Horizons      |                   | ([http://soi                    |
| (NHORIZ)      |                   | ldatamart.nrcs.usda.gov](http:/ |
|               |                   | /soildatamart.nrcs.usda.gov/)). |
|               |                   | The third horizon from SDM was  |
|               |                   | excluded because it is bedrock. |
+---------------+-------------------+---------------------------------+
| Horizon       | 10 cm (HORIZN =   | NRCS Soil Data Mart (SDM)       |
| Thickness     | 1)                | ([http://soi                    |
| (THKNS)       |                   | ldatamart.nrcs.usda.gov](http:/ |
|               | 15 cm (HORIZN =   | /soildatamart.nrcs.usda.gov/)). |
|               | 2)                |                                 |
+---------------+-------------------+---------------------------------+
| Bulk Density  | 1.55 g/cm^3^      | NRCS Soil Data Mart (SDM)       |
| (BD)          | (HORIZN = 1)      | ([http://soi                    |
|               |                   | ldatamart.nrcs.usda.gov](http:/ |
|               | 1.55 g/cm^3^      | /soildatamart.nrcs.usda.gov/)). |
|               | (HORIZN = 2)      | Midpoint of the reported range. |
|               |                   | PRZM Scenario Guidance (EPA,    |
|               |                   | 2004).                          |
+---------------+-------------------+---------------------------------+
| Initial Water | 0.168 cm^3^/cm^3^ | NRCS Soil Data Mart (SDM);      |
| Content       | (HORIZN =1)       | values are mean 1/3-bar water   |
| (THETO)       |                   | contents of Cieneba coarse      |
|               | 0.168 cm^3^/cm^3^ | sandy loam soils.               |
|               | (HORIZN =2)       |                                 |
+---------------+-------------------+---------------------------------+
| Compartment   | 0.1 cm (HORIZN =  | NRCS Soil Data Mart (SDM)       |
| Thickness     | 1)                | ([http://soi                    |
| (DPN)         |                   | ldatamart.nrcs.usda.gov](http:/ |
|               | 5 cm (HORIZN = 2) | /soildatamart.nrcs.usda.gov/)). |
|               |                   | PRZM Scenario Guidance (EPA,    |
|               |                   | 2004).                          |
+---------------+-------------------+---------------------------------+
| Field         | 0.168 cm^3^/cm^3^ | NRCS Soil Data Mart (SDM);      |
| Capacity      | (HORIZN =1)       | values are mean 1/3-bar water   |
| (THEFC)       |                   | contents of Cieneba coarse      |
|               | 0.168 cm^3^/cm^3^ | sandy loam soils.               |
|               | (HORIZN =2)       |                                 |
+---------------+-------------------+---------------------------------+
| Wilting Point | 0.08 cm^3^/cm^3^  | NRCS Soil Data Mart (SDM);      |
| (THEWP)       | (HORIZN =1)       | values are mean 15-bar water    |
|               |                   | contents of Cieneba coarse      |
|               | 0.08 cm^3^/cm^3^  | sandy loam soils.               |
|               | (HORIZN =2)       |                                 |
+---------------+-------------------+---------------------------------+
| Organic       | 0.44% (HORIZN =   | NRCS SDM; values for horizons 1 |
| Carbon        | 1)                | to 3 = mean %OM / 1.724. PRZM   |
| Content (OC)  |                   | Scenario Guidance (EPA, 2004).  |
|               | 0.44% (HORIZN =   |                                 |
|               | 2)                |                                 |
+---------------+-------------------+---------------------------------+

![](media/image1.png){width="8.75625in" height="5.324305555555555in"}

**Figure 1. 2002 harvested acres for avocados based on USDA Census of
Agriculture for California and conterminous United States (inset)**
Estimates do not include data for individual farms which NASS has
excluded to protect the identify of individual farms.

  --------------------------------------------------------------------------------- --------- -------- ---------- ------------------- ------------- -------- --------- ---------- ----------- ----------- --------- --------------------
  **Table 5. Avocado Bearing Soils of San Diego, Santa Barbara, and Ventura                                                                                                                                         
  Counties (California) Ranked by Area.**                                                                                                                                                                           

  Soil                                                                              Total     \% Area  Drainage   Avocados-IrrYield   Erodibility   Slopes   pH        OM (%)     \% Sand     \% Silt     \% Clay   Avocados-NIrrYield
                                                                                    Acreage                       (boxes)                           (%)                                                             (boxes)

  [CIENEBA](http://ortho.ftw.nrcs.usda.gov/osd/dat/C/CIENEBA.html)                  332,986   37.12%   C          250-400             0.24-0.32     9-75     5.8-6.5   0.75       67.9-68.5   19-19.6     12.5      \-

  [VISTA](http://ortho.ftw.nrcs.usda.gov/osd/dat/V/VISTA.html)                      74,863    8.35%    B          500-615             0.28-0.32     15-65    6.7       0.75       65.4-66.8   22.2-23.6   11        \-

  [GAVIOTA](http://ortho.ftw.nrcs.usda.gov/osd/dat/G/GAVIOTA.html)                  62,334    6.95%    D          250                 0.28-0.55     5-75     6.3-7.6   0.75       66.1-66.8   19.2-19.9   14        \-

  [TERRACE                                                                          57,147    6.37%    \--        375                 \-            9-75     \-        0          \-          \-          \-        \-
  ESCARPMENTS](http://ortho.ftw.nrcs.usda.gov/osd/dat/T/TERRACE_ESCARPMENTS.html)                                                                                                                                   

  [MAYMEN](http://ortho.ftw.nrcs.usda.gov/osd/dat/M/MAYMEN.html)                    49,991    5.57%    D          200                 0.28          15-75    5.3-5.8   0.75-1.5   43-68.8     16.2-39.5   15-17.5   \-

  [ARNOLD](http://ortho.ftw.nrcs.usda.gov/osd/dat/A/ARNOLD.html)                    38,078    4.25%    A          325-825             0.17-0.28     5-75     5.6-6.7   0.75       78.5-96     1.5-16.5    2.5-5     \-

  [MOCHO](http://ortho.ftw.nrcs.usda.gov/osd/dat/M/MOCHO.html)                      34,528    3.85%    B          1000                0.17-0.28     0-9      8.2       3          18.1-68.8   16.2-50.9   15-31     \-

  [FRIANT](http://ortho.ftw.nrcs.usda.gov/osd/dat/F/FRIANT.html)                    34,451    3.84%    D          150                 0.2           30-70    6.3       1.5        66.1        19.9        14        \-

  [LINNE](http://ortho.ftw.nrcs.usda.gov/osd/dat/L/LINNE.html)                      26,767    2.98%    C          250                 0.2-0.32      30-75    8.2       2-3.5      18.1-35.4   33.6-50.9   31        \-

  [SAN BENITO](http://ortho.ftw.nrcs.usda.gov/osd/dat/S/SAN_BENITO.html)            25,075    2.80%    B          300                 0.17-0.2      9-50     7.2-7.6   2.5        35.4        33.6        31        \-

  [CORRALITOS](http://ortho.ftw.nrcs.usda.gov/osd/dat/C/CORRALITOS.html)            21,924    2.44%    A          300-330             0.15-0.28     0-15     5.8-6.7   0.75       80.5-96     1.5-17      2.5       \-

  [LOS OSOS](http://ortho.ftw.nrcs.usda.gov/osd/dat/L/LOS_OSOS.html)                21,084    2.35%    C          250                 0.17-0.28     30-50    6.1-6.1   2.5-3      35.4        33.6        31        \-

  [BOTELLA](http://ortho.ftw.nrcs.usda.gov/osd/dat/B/BOTELLA.html)                  18,581    2.07%    B          400                 0.2-0.28      0-15     6.5       3-4        34.2-41.6   33.6-37.4   21-31     \-

  [NACIMIENTO](http://ortho.ftw.nrcs.usda.gov/osd/dat/N/NACIMIENTO.html)            11,550    1.29%    C          325-1000            0.28-0.32     9-50     8.2       2-3        18.1        50.9        31        \-

  [SAN ANDREAS](http://ortho.ftw.nrcs.usda.gov/osd/dat/S/SAN_ANDREAS.html)          10,936    1.22%    B          325-350             0.24-0.28     9-45     5.8-6.5   2.5        70.5        16.5        13        \-

  [MARINA](http://ortho.ftw.nrcs.usda.gov/osd/dat/M/MARINA.html)                    10,843    1.21%    B          450-470             0.24          0-9      5.8       0.75       96          1.5         2.5       \-

  [PICO](http://ortho.ftw.nrcs.usda.gov/osd/dat/P/PICO.html)                        9,622     1.07%    B          400                 0.2           0-9      8.2       2.5        65.1        18.9        16        \-

  [BALLARD](http://ortho.ftw.nrcs.usda.gov/osd/dat/B/BALLARD.html)                  9,036     1.01%    B          800-900             0.28          0-15     5.6-6.1   2          68.8        16.2        15        \-

  [ANACAPA](http://ortho.ftw.nrcs.usda.gov/osd/dat/A/ANACAPA.html)                  8,355     0.93%    B          900                 0.28          0-9      7.2       2          67.9        19.6        12.5      \-

  [AYAR](http://ortho.ftw.nrcs.usda.gov/osd/dat/A/AYAR.html)                        6,803     0.76%    D          200                 0.2           30-75    7.7-8.2   2          26.1        28.9        45        \-

  [TODOS](http://ortho.ftw.nrcs.usda.gov/osd/dat/T/TODOS.html)                      6,670     0.74%    D          250-900             0.24          9-50     6.3       3          35.4        33.6        31        \-

  [GOLETA](http://ortho.ftw.nrcs.usda.gov/osd/dat/G/GOLETA.html)                    5,652     0.63%    B          1000                0.24-0.28     0-9      7.2-7.5   3          45.4-70.5   16.5-41.6   13        \-

  [ROUGH BROKEN                                                                     4,520     0.50%    \--        375                 \-            15-50    \-        0          \-          \-          \-        \-
  LAND](http://ortho.ftw.nrcs.usda.gov/osd/dat/R/ROUGH_BROKEN LAND.html)                                                                                                                                            

  [MILPITAS](http://ortho.ftw.nrcs.usda.gov/osd/dat/M/MILPITAS.html)                3,626     0.40%    D          300                 0.37          15-50    6.1-6.7   1.5        68.8        16.2        15        \-

  [CAMARILLO](http://ortho.ftw.nrcs.usda.gov/osd/dat/C/CAMARILLO.html)              2,658     0.30%    C          250                 0.24-0.43     0-2      8.2       2.5        18.1-66.8   19.2-50.9   14-31     \-

  [DIABLO](http://ortho.ftw.nrcs.usda.gov/osd/dat/D/DIABLO.html)                    2,458     0.27%    D          200                 0.2-0.24      30-50    7.3-7.5   2.5        22.1-23.3   27.9-29.2   47.5-50   \-

  [BALLARD VARIANT](http://ortho.ftw.nrcs.usda.gov/osd/dat/B/BALLARD_VARIANT.html)  1,254     0.14%    B          325                 0.28          2-9      6.1       1.5        68.8        16.2        15        \-

  [CORTINA](http://ortho.ftw.nrcs.usda.gov/osd/dat/C/CORTINA.html)                  1,177     0.13%    B          325                 0.28          9-15     6.7       0.75       67.2        15.3        17.5      \-

  [ORTHENTS](http://ortho.ftw.nrcs.usda.gov/osd/dat/O/ORTHENTS.html)                1,039     0.12%    B          375                 \-            50-75    \-        \-         \-          \-          \-        \-

  [CAMARILLO                                                                        903       0.10%    C          500                 0.32          0-2      8.2       2.5        68.1        14.4        17.5      \-
  VARIANT](http://ortho.ftw.nrcs.usda.gov/osd/dat/C/CAMARILLO_VARIANT.html)                                                                                                                                         

  [BOTELLA VARIANT](http://ortho.ftw.nrcs.usda.gov/osd/dat/B/BOTELLA_VARIANT.html)  808       0.09%    B          1000                0.15-0.17     2-15     5.8       2.5        18.1-35.4   33.6-50.9   31        \-

  [ESCARPMENT](http://ortho.ftw.nrcs.usda.gov/osd/dat/E/ESCARPMENT.html)            629       0.07%    \--        375                 \-            75-99    \-        \-         \-          \-          \-        \-

  [POSITAS](http://ortho.ftw.nrcs.usda.gov/osd/dat/P/POSITAS.html)                  616       0.07%    D          300                 0.37          30-50    5.8       1.5        67.5        21          11.5      \-
  --------------------------------------------------------------------------------- --------- -------- ---------- ------------------- ------------- -------- --------- ---------- ----------- ----------- --------- --------------------

***Works Cited***

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, DC.

EPA. 2004. 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, DC.

EPA. 2005. Irrigation Guidance for developing PRZM Scenarios. June 15,
2005.

Oster JD, Arpaia ML. 2006. Effects of salinity and applied water on
yields of 'Hass' avocado on Mexican seedling rootstock. Seminario:
Manejo del riego y suelo en el cultivo del palto. 27-28 de Septiembre de
2006. 14 pages.

USDA. 1990. Davis, F.M., R.A. Leonard, W.G. Knisel. GLEAMS User Manual,
Version 1.8.55. U.S. Department of Agriculture, Agricultural Research
Service (ARS), Southeast Watershed Research Laboratory, Tifton, GA.
SEWRL-030190FMD.

USDA. 1999a. Crop Profile for Avocados in California. U.S. Department of
Agriculture, Pest Management Centers. July 1999. Online at:
<http://www.ipmcenters.org/cropprofiles/caavocados.html>

USDA. 1999b. Official Series Description -- CIENEBA Series. U.S.
Department of Agriculture, Natural Resources Conservation Service
(NRCS). May 1999. Online at:
<http://ortho.ftw.nrcs.usda.gov/osd/dat/C/CIENEBA.html>.

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).

USDA. 2002. 2002 Census of Agriculture. U.S. Department of Agriculture,
National Agricultural Statistics Service (NASS). Online at:
<http://www.nass.usda.gov/census/census02/preliminary/2002censusdates.htm>.

USDA. 2006. Soil Survey Areas of San Diego, Santa Barbara, and Ventura
Counties. U.S. Department of Agriculture, Natural Resources Conservation
Service (NRCS), Soil Data Mart. March 1, 2006. Online at:
[http://soildatamart.nrcs.usda.gov](http://soildatamart.nrcs.usda.gov/).