Hero Image

Contact Us

UC Cooperative Extension Ventura County
669 County Square Dr. Suite 100
Ventura CA 93003
Phone: 805.645.1451
Fax: 805.645.1474

Office Hours
Our offices are currently closed due to the COVID-19 pandemic, and our team is telecommuting from home. We are available via phone and email. 

Click here for our office directory: Contact/Staff Info

 

General Soil Map

The general soil map in this publication shows, in color, the soil associations in the Ventura Area. A soil association is a landscape that has a distinctive proportional pattern of soils. It normally consists of one or more major soils and at least one minor soil, and it is named for the major soils. The soils in one association may occur in another, but in a different pattern.

A map showing soil associations is useful to people who want a general idea of the soils in an area, who want to compare different parts of an area, or who want to know the location of large tracts that are suitable for a certain kind of farming or other land use. Such a reap is also useful in determining the value of an association for a watershed, for wildlife habitat, for engineering projects, for recreational areas, and for community development. A general soil map is not suitable for planning the management of a farm or field, because the soils in any one association ordinarily differ in slope, depth, stoniness, drainage, and other characteristics that affect management.

The 14 soil associations in the Ventura Area are described in the following paragraphs. Four of the associations are on alluvial fans and plains and in basins, two are on terraces, and eight are on uplands.

Level to Moderately Sloping, Excessively Drained to Poorly Drained Soils of the Alluvial Fans, Plains, and Basins

These soils are well-drained to excessively drained loamy sands to silty clay barns on alluvial fans and plains, and poorly drained loamy sands to silty clay barns in basins. They formed in alluvium derived predominantly from sedimentary rocks and to a lesser extent from basic igneous rocks.

These soils are on the Oxnard Plain, in Conejo Valley, Hidden Valley, Las Posas Valley, Ojai Valley, Pleasant Valley, Russell Valley, Santa Rosa Valley, Simi Valley, Tierra Rejada Valley, and the Santa Clara and Ventura River valleys. Elevations range from sea level to 1,700 feet. The annual rainfall commonly ranges from 14 to 20 inches, and the frost-free season from 280 to 350 days. The average annual air temperature is between 59° and 62° F.

The soils in this group are used extensively for cultivated crops and orchards and for urban development. In uncultivated areas the vegetation consists of annual grasses, forbs, brush, and scattered oaks.

Four of the associations in the Ventura Area are in this group. They make up 33 percent of the Area and include most of the cultivated acreage.



1.      Pico-Metz-Anacapa Association

Level to moderately sloping, very deep, well-drained sandy barns and very deep, somewhat excessively drained loamy sands

The main areas of this association are in Las Posas Valley, Pleasant Valley, Santa Rosa Valley, and the Santa Clara and Ventura River valleys. The soils formed in deep alluvium derived predominantly from sedimentary rocks. The plant cover in uncultivated areas consists of annual grasses, forbs, and scattered oaks. Slopes range from 0 to 9 percent. Elevations range from 25 to 1,000 feet. The annual rainfall ranges from 14 to 18 inches, and the frost-free season from about 300 to 350 days. The average annual air temperature is between 60° and 62° F.

This association occupies about 7 percent of the survey Area. Pico soils make up about 30 percent of the association, Metz soils about 30 percent, and Anacapa soils about 20 percent. Cortina and Corralitos soils make up the remaining 20 percent.

Pico, Metz, and Anacapa soils are 60 inches or more deep. P1cc soils are well drained and have a surface layer of grayish-brown, calcareous sandy loam underlain by light brownish-gray, calcareous loam and sandy loam. Metz soils are somewhat excessively drained and have a surface layer of pale-brown, calcareous loamy sand underlain by light brownish-gray, calcareous, stratified sand and sandy loam. Anacapa soils are well drained and have a surface layer of grayish-brown, neutral to moderately alkaline sandy loam underlain by grayish- brown, moderately alkaline, calcareous coarse sandy loam.

The soils of this association are some of the most productive in the survey Area. They are used for irrigated vegetables, citrus crops and field crops, strawberries, walnuts, and avocados, and to a lesser extent for range. Some areas have been used for urban development.

2.      Mocho-Sorrento-Garretson Association

Level to moderately sloping, very deep, well-drained loams to silty clay loams

The main areas of this association are in Conejo Valley, Hidden Valley, Las Posas Valley, Russell Valley, Sirni Valley, and the Santa Clara and Ventura River valleys. The soils formed in deep alluvium derived predominantly from sedimentary rocks. The plant cover in uncultivated areas consists of annual grasses, forbs, and scattered oaks. Slopes range from 0 to 9 percent. Elevations range from 25 to 1,700 feet. The annual rainfall ranges from 14 to 20 inches, and the frost-free season from about 280 to 350 days. The average annual air temperature is between 600 and 62° F.

This association occupies about 14 percent of the survey Area. Mocho soils make up about 35 percent of the association, Sorrento soils about 25 percent, and Garretson soils about 10 percent. Cropley, Salinas, Vina, and Zamora soils make up the remaining 30 percent.

Mocho, Sorrento, and Garretson soils are well drained and are 60 inches or more deep. Mocho soils have a surface layer of grayish-brown, calcareous loam underlain by grayish-brown and light grayishbrown, calcareous loam. Sorrento soils have a surface layer of grayish-brown, neutral to mildly alkaline loam underlain by grayish-brown and light brownish-gray, moderately alkaline loam that is calcareous in the lower part. Garretson soils have a surface layer of grayish-brown and yellowish-brown, slightly acid loam underlain by yellowish-brown and pale-brown, mildly alkaline loam and gravelly fine sandy loam.

The soils of this association are some of the most productive in the survey Area. They are used for irrigated vegetables, citrus crops and field crops, walnuts, and avocados. Some areas are used for range, and some for urban development.

3.      Camarillo-Hueneme-Pacheco Association

Level and nearly level, very deep, poorly drained loamy sands to silty clay loams

This association occurs mainly on the Oxnard Plain. The soils formed in deep, stratified alluvium derived predominantly from sedimentary rocks. The plant cover in uncultivated areas consists of salt-tolerant grasses, forbs, and shrubs. Slopes range from 0 to 2 percent. Elevations range from 25 to 250 feet. The annual rainfall is 14 to 16 inches, and the frost-free season 300 to 350 days. The average annual air temperature is 59° or 60° F.

This association occupies about 8 percent of the survey Area. Camarillo soils make up about 55 percent of the association, Hueneme soils about 30 percent, and Pacheco soils about 15 percent.

Camarillo, Hueneme, and Pacheco soils are poorly drained and are 60 or more inches deep. Camarillo soils have a surface layer of grayish-brown, calcareous sandy loam underlain by mottled grayish-brown, pale-brown, and light-gray, calcareous fine sand to fine sandy clay loam. Hueneme soils have a surface layer of grayish-brown, calcareous loamy fine sand and light sandy loam underlain by mottled grayish- brown and light-gray, calcareous sandy loam, loamy sand, and sand. Pacheco soils have a surface layer of dark-gray, mildly and strongly alkaline silty clay loam that becomes calcareous in the lower part. The underlying layer is mottled light brownish-gray, calcareous silty clay loam.

The soils of this association are some of the most productive in the survey Area. They are used for irrigated vegetables, field crops, lemons, and strawberries, and for urban development. Most are are artificially drained. In undrained areas there is a seasonal water table within a depth of 2 feet. Periodically the soils contain soluble salts.

4. Riverwash-Sandy Alluvial Land-Coastal Beaches

Association level to gently sloping, excessively drained to poorly drained, stratified sandy, gravelly, and cobbly material.

The main areas of this association are in the Santa Clara and Ventura River valleys and along the coast from Point Mugu to the mouth of the Ventura River. ‘the soils formed in deep alluvium derived predominantly from sedimentary rocks. The plant cover consists of annual grasses, beach grasses, brush, willows, and scattered cottonwoods. Slopes range from 0 to 5 percent. Elevations range from sea level to 800 feet. The annual rainfall is 14 to 17 inches, and the frost-free season is about 300 to 350 days. The average annual air temperature is between 59° and 62° F.

This association occupies about 4 percent of the survey Area. Riverwash makes up about 35 percent of the association, Sandy alluvial land about 30 percent, and Coastal beaches about 15 percent. Fill land and Tidal flats make up the remaining 20 percent.

Riverwash and Sandy alluvial land are excessively drained. Coastal beaches has variable drainage. Al consist of highly stratified, water- and wind-deposited, stony, cobbly, and gravelly sand, loamy sand, and sandy loam. They contain only a snail amount of silt and clay. They are subject to flooding, scouring, and deposition during and immediately following storms.

The areas in this association have little or no value for farming. They are used mainly for recreation and for watershed. Limited acreages of Sandy alluvial land are used for range, for citrus crops, and for urban development.

Level to Moderately Steep, Well Drained and Moderately Well_Drained.Soils of the_Terraces

The soils in this group are well drained and moderately well drained very fine sandy loams to silty clay loams that have a moderately slowly to very slowly permeable sandy clay loam to sandy clay subsoil. Most of these soils formed on old terraces in alluvium derived from sedimentary rocks. A few formed on old alluvial fans.

These soils are in Conejo Valley, Las Posas Valley, Ojai Valley, Upper Ojai Valley, Santa Ama Valley, Santa Rosa Valley, Simi Valley, Tierra Rejada Valley, and the Santa Clara River valley. They are also on Las Posas Heights and in the area north of Moorpark. Elevations range from 100 to 1,700 feet. The annual rainfall commonly ranges from 14 to 21 inches, and the frost-free season from 250 to 330 days. The average annual air temperature is between 600 and 62° F.

The soils in this group are used for range and dryland pasture, for watershed, for citrus crops and field crops, and for urban development. In uncultivated areas the vegetation consists of annual grasses, forbs, brush, and scattered oaks.

Two of the associations in the Ventura Area are in this group. They make up about 7 percent of the Area.

5. Rincon-Huerhuero-Azule Association

Level to moderately steep, very deep, well drained and moderately well drained very fine sandy barns to silty clay barns that have a slowly and very slowly permeable sandy clay subsoil

The main areas of this association are in Conejo Valley, Las Posas Valley, Santa Rosa Valley, Simi Valley, Tierra Rejada Valley, and the Santa Clara River valley, on Las Posas Heights, and in the area separating South Mountain, Oak Ridge, and Moorpark. The soils formed in alluvium derived predominantly from sedimentary rocks. The plant cover in uncultivated areas consists of annual grasses, forbs, brush, and scattered oaks. Slopes range from 0 to 30 percent. Elevations range from 100 to 500 feet. The annual rainfall ranges from 14 to 20 inches, and the frost-free season from about 250 to 330 days. The average annual air temperature is between 60° and 62° F.

This association occupies about 5 percent of the survey Area. Rincon soils make up about 35 percent of the association, Huerhuero soils about 30 percent, and Azule soils about 20 percent. Chesterton and Soper soils make up the remaining 15 percent.

Rincon soils are well drained and are 60 inches or more deep. They have a surface layer of dark- gray, slightly acid silty clay loam. The subsoil is dark grayish-brown and brown, neutral to moderately alkaline sandy clay and sandy clay loam that becomes calcareous with increasing depth. The substratum is yellowish-brown, calcareous, stratified sandy clay loam and sandy loam.

Huerhuero soils are moderately well drained and have an effective rooting depth of 8 to 30 inches. They have a surface layer of grayish-brown and dark grayish-brown, slightly acid very fine sandy loam. This layer is underlain by a thin layer of gray, medium acid very fine sandy loam. The subsoil is brown and pale-brown, neutral and moderately alkaline sandy clay and sandy clay loam. The substratum is brown, moderately alkaline, calcareous very fine sandy loam.

Azule soils are well drained and are 60 inches or more deep. They have a surface layer of grayish- brown, medium acid loam abruptly underlain by a subsoil of brown, slightly acid sandy clay. The substratum is brown, mildly alkaline sandy clay loam.

The soils of this association are used for range, for citrus crops and field crops, and for urban development. The lesser slopes are also used for vegetables.

6. Ojai-Sorrento, Heavy Variant, Association

Level to moderately steep, very deep, well-drained very fine sandy barns and clay loans that have a slowly and moderately slowly permeable sandy clay loam and heavy clay loam subsoil

The main areas of this association are in Ojai Valley, Santa Ana Valley, and Upper Ojai Valley. The soils formed on fans and terraces, in alluvium derived predominantly from sedimentary rocks. The plant cover in uncultivated areas consists of annual grasses, brush, and scattered oaks. Slopes range from 0 to 30 percent. Elevations range from 25 to 1,700 feet. The annual rainfall ranges from 14 to 21 inches, and the frost-free season from about 250 to 300 days. The average annual air temperature is about 61° F.

This association occupies about 2 percent of the survey Area. Ojai soils make up about 65 percent of the association, and Sorrento soils, heavy variant, about 25 percent. Kimball soils make up the remaining 10 percent.

Ojai soils are well drained and are 60 inches or more deep. They have a surface layer of brown, medium acid and slightly acid very fine sandy loam. The subsoil is reddish-brown, slightly acid light to heavy sandy clay loam. The substratum is light reddish-brown, slightly acid very cobbly and gravelly light clay.

Sorrento soils, heavy variant, also are well drained and are 60 inches or more deep. They have a surface layer of dark grayish-brown, slightly acid clay loam. The subsoil is dark grayish-brown, neutral heavy clay loam. The substratum is brown, moderately alkaline heavy clay loam.

The soils of this association are used for range, for field crops and citrus crops, and for urban development.

Moderately Sloping to Very Steep, Well-Drained and Excessively Drained Soils of the Uplands

The soils of the uplands are well-drained to excessively drained sands to silty clay barns. They are shallow to very deep over softly consolidated sediments, sandstone, shale, or basic igneous rocks.

These soils are in the hills west of the Ventura River and north of the Santa Clara River, and on South Mountain, Oak Ridge, Santa Susana Mountains, Simi Hills, and Santa Monica Mountains. Elevations range from 50 to 3,000 feet. The annual rainfall commonly ranges from 14 to 22 inches, and the frostfree season from 250 to 300 days. The average annual air temperature is between 60° and 62° F.

The soils in this group are used for range, for watershed, and for urban development. The lesser slopes are ued for orchards and field crops. In uncultivated areas the vegetation consists of annual grasses, forbs, brush, and scattered oaks.

Eight associations in the Ventura Area are in this group. They make up about 60 percent of the Area.

7. San Benito-Nacimiento-Linne Association

Strongly sloping to very steep, well-drained clay barns and silty clay loans that are moderately deep to deep over shale or sandstone

The main areas of this association are in the uplands north of the Santa Clara River, on South Mountain and Oak Ridge, and around Erbes Road in Thousand Oaks. The soils are underlain by softly consolidated sediments or by soft to firm shale or sandstone. The plant cover in uncultivated areas consists of annual grasses, forbs, brush, and scattered oaks. Slopes range from 9 to 75 percent. Elevations range from 100 to 2,000 feet. The annual rainfall ranges from 14 to 20 inches, and the frost-free season from about 260 to 300 days. The average annual air temperature is between 60° and 62° p.

This association occupies about 15 percent of the survey Area. San Benito soils make up about 40 percent of the association, Nacimiento soils about 20 percent, and Linne soils about 15 percent. Diablo and Soper soils make up the remaining 25 percent.

San Benito soils are well drained and are 48 to 60 inches or more deep. They have a surface layer of dark grayish-brown, moderately alkaline clay loam and a substratum of grayish-brown and light yellowish-brown, calcareous clay loam. They are underlain by softly consolidated sediments.

Nacimiento soils are well drained and are 24 to 40 inches deep. They are grayish-brown, calcareous silty clay loam throughout the profile. They are underlain by firm, calcareous shale.

Linne soils are well drained and are 24 to 48 inches deep. They have a surface layer of gray, calcareous silty clay loam. The next layer is light brownish-gray, calcareous silty clay loam. Below this is calcareous shale.
The soils of this association are used for range, for watershed, for citrus crops, field crops, and avocados, and for urban development.

8. Castaic-Balcom-Saugus Association

Moderately sloping to very steep, well-drained sandy loans to silty clay learns that are moderately deep to deep over sandstone and shale

The main areas of this association are on both sides of the Santa Clara River and at the Los Angeles County line, north of the town of Piru, or the northern and, southern slopes of South Mount air and on the southern slopes of Sulphur Mountain in the Wheeler Canyon area. At a depth of more than 20 inches, the soils are underlain by soft shale c sandstone. The plant cover in uncultivated areas consists of annual grasses, brush, and scattered oaks. Slopes range from 9 to 75 percent. Elevatitions range from SO to 2,500 feet. The annual rainfall 14 to 20 inches, and the frost-free season is about 230 to 300 days. The average annual air temperature is between 60° and 62° P.

This association occupies about 8 percent of the survey Area. Soils in the Castaic-Balcom complex make up about 45 percent of the association; Castaic and Saugus soils about 35 percent; and Saugus soils about 10 percent. Badland, Landslide: and Terrace escarpments make up the remaining 10 percent.

Castaic soils are well drained and are 22 to 40 inches deep. They have a surface layer of grayish-brown, slightly acid and neutral silty clay loam. Below this is light brownish-gray, calcareous. shale that crushes easily to silty clay loam.

Balcom soils are well drained and are 22 to 40 inches deep. They have a surface layer of grayish- brown and light brownish-gray, calcareous loam. Below this is pale-olive, calcareous shale that crushes easily to loam. Saugus soils are well drained and are 48 to 60 inches deep. They have a surface layer of brown and yellowish-brown, neutral and slightly acid sandy loam. The substratum is light yellowish-brow slightly acid sandy loam that grades to pale-brown, slightly acid, firm sandstone.
The soils of this association are used for range for watershed, for citrus crops and field crops, and for urban development.

9. Calleguas-Arnold Association

Strongly sloping to steep, well-drained shaly loans that are shallow over shale or sandstone, and somewhat excessively drained sands that are very deep over sandstone

The main areas of this association are on the southwestern slopes of Sulphur Mountain and the northwestern slopes of South Mountain, on Oak Ridge and on the hills around Simi Peak. The soils are underlain by soft sandstone and hard shale. The plant cover consists of annual grasses, forbs, and brush. Slopes range from 9 to 50 percent. Elevations range from 100 to 2,200 feet. The annual rainfall is 14 to 20 inches, and the frost-free season about 250 to 300 days. The average annual air temperature is between 60° and 62° p.

This association occupies about 9 percent of the survey Area. Calleguas soils make up about 55 percent of the association, soils in the Calleguas-Arnold complex about 20 percent, and Arnold soils about s percent. San Andreas soils, Badland, Landslides, and Gullied land make up most of the remaining 20 percent.

Calleguas soils are well drained and are less than 20 inches deep. They have a surface layer of pale-brown, calcareous shaly loam underlain by pale-brown, calcareous very shaly loam. Below this is hard, fractured, calcareous shale.

Arnold soils are somewhat excessively drained and are 60 inches or more deep. They have a surface layer of light brownish-gray, slightly acid sand underlain by very pale brown, medium acid and strongly acid sand and fine sand. The underlying sandstone is soft enough that it does not adversely affect root and water penetration.

The soils of this association are used for range and for watershed. Urban use is increasing on the more gentle slopes.

10. Gazes-Santa Lucia Association

Moderately steep to very steep, well-drained silty clay learns and shaly silty clay learns that are moderately deep to deep over fractured shale

The main areas of this association are on Sulphur Mountain, Oak Ridge, and along the southeast Los Angeles-Ventura County line. At a depth of more than 20 inches, the soils are underlain by shale. The plant cover in uncultivated areas consists of annual grasses, brush, and scattered oaks. Slopes range from 15 to 75 percent. Elevations range from 100 to 2,500 feet. The annual rainfall is 14 to 22 inches, and the frost-free season about 250 to 300 days. The average annual air temperature is between 60° and 62° F.

This association occupies about 3 percent of the survey Area. Gazos soils make up about 70 percent of this association, and Santa Lucia 501i5 about 20 percent. Badland and Gullied land make up the remaining 10 percent.

Gazos soils are well drained and are 24 to 46 inches deep. They have a surface layer of grayish- brown, neutral silty clay loam underlain by light brownish-gray and pale-brown, slightly acid and medium acid very shaly silty clay loam. Below this is fractured shale.

Santa Lucia soils are well drained and are 20 to 36 inches deep. They have a surface layer of dark-gray and gray, medium acid shaly silty clay loam underlain by gray, medium acid very shaly silty clay loam. They are 15 to 50 percent shale throughout the profile. The underlying material is fractured, diatomaceous shale.

The soils of this association are used mainly for range and for watershed. The more gentle slopes are used for urban development and for citrus crops.

11. Millsholm—Malibu—Los Osos Association

Strongly sloping to very steep, well-drained learns and clay barns that have a clay loam and clay subsoil and are shallow to deep over sandstone and shale

The main areas of this association are in the Santa Monica Mountains, between Point Mugu and the Los Angeles County line, north of the towns Of Piru and Fillmore, and on Sulphur Mountain, Red Mountain, and the Simi Hills. The soils are underlain by sandstone and shale. The plant cover in uncultivated areas consists of annual grasses, forbs, brush, and scattered oaks. Slopes range from 9 to 75 percent. Elevations range from 100 to 2,500 feet. The annual rainfall is 14 to 20 inches, and the frost-free season is about 250 to 300 days. The average annual air temperature is 600 F.

This association occupies about 6 percent of the survey Area. Millsholm soils make up about 40 percent of the association, Malibu soils about 10 percent, Los Osos soils about 15 percent, and soils in the Millsholm-Malibu complex about 25 percent. Sedimentary rock land and Gullied land make up the remaining 10 percent.

Millsholm soils are well drained and are less than 20 inches deep. They have a surface layer of brown, medium acid loam and a subsoil of brown, medium acid light clay loam. They are underlain by hard, well-fractured shale and sandstone.

Malibu soils are well drained and are 23 to 36 inches deep. They have a surface layer of brown, medium acid loam abruptly underlain by a yellowish-red, medium acid clay subsoil. Below this is hard, fractured shale and sandstone.

Los Osos soils are well drained and are 22 to 48 inches deep. They have a surface layer of dark- brown, slightly acid clay loam and a subsoil of dark- brown, slightly acid and neutral clay. They are underlain by decomposing shale.

The soils of this association are used mainly for range and for watershed. The lesser slopes are used for citrus crops and field crops and for urban purposes.

12. Sespe-Lodo Association

Moderately steep to very steep, well-drained clay barns that are moderately deep to deep over sandstone or shale, and somewhat excessively drained barns that are shallow over shale

The main areas of this association are in the hills between Ojai Valley and Upper Ojai Valley, on Red Mountain, and along the northwest boundary of the survey Area. The soils are underlain by hard sandstone and shale. The plant cover in uncultivated areas consists of annual grasses brush, and scattered oaks . Slopes range from 15 to 75 percent. Elevations range from 300 to 2,000 Feet. the annual rainfall is 15 to 22 inches , and the frost-free season is about 250 to 280 days . The average annual temperature is 61° F.

This association occupies about 4 percent of the survey Area. Sespe soils make up about 60 percent of the association, and Lodo soils about 25 percent . Sedimentary rock land, Gullied land, and Terrace escarpments make up the remaining 15 percent.

Sespe soils are well drained and are 24 to 48 inches deep . They have a surface layer of brown medium acid clay loam and a subsoil of reddish-brown, slightly acid sandy clay. They are underlain by hard sandstone.

Lodo soils are somewhat excessively drained and are less than 20 inches deep . They have a surface layer of reddish-brown, slightly acid heavy loam and medium acid gravelly light clay loam underlain by hard, fractured , reddish-brown shale . Rock out-crop covers 2 to 10 percent of the area.

The soils of this association are used primarily for range and for watershed. The lower slopes are used for citrus crops and for urban development

13. Sedimentary Rock Land—Gaviota Association

Moderately steep to very steep, excessively drained rock land and well-drained sandy loams that are shallow over sandstone

The main areas of this association are on the Santo Susana Mountains , the hills north of the town of Piru, and the south face of Sulphur Mountain. At a depth of loss than 21) inches, these soils are underlain by sandstone and shale. The plant cover consists of annual grasses, brush, and scattered oaks. Slopes range from 15 to 73 percent. Elevations range from 100 to 2,500 foot . The annual rainfall is 15 to 20 inches, and the frost-free season is about 250 to 270 days. The average annual air temperature Is 60° F.

This association occupies about 6 percent of the survey Area. Sedimentary reek land makes up about 55 percent of the association, and Gaviota soils about 30 percent. Badland and Gullied land make up the remaining 15 percent.

Sedimentary rock load is excessively drained. It has a thin mantle of relatively stable soil material. Rock outcrop covers more than 25 percent of the area. This land type is typically nearly barren or has only sparse brush cover.

Gaviota soils are well drained. They have a surface layer of yellowish-brown , neutral sandy loom and are underlain by sandstone rock at a depth of 8 to 20 inches . Rock outcrop covers about 5 to 10 percent of the area

The soils of this association are used for watershed and for range.

14. Hamhright-Igneous Rock Land-Gilroy AssocAssociation

Rock land and strongly sloping to very steep, well-drained clay loams that are shallow to moderately deep over basic igneous rock

This association is in the southeastern corner of the survey Area, between the Oxnard Plain and the Los Angeles County line. The plant cover in uncultivated areas consists of annual grasses , brush and scattered oaks . Slopes range from 9 to 75 percent . Elevations range from 100 to 3,000 feet. The annual rainfall is 15 to 22 inches , and the frost-free season is about 250 to 300 das. The average annual air temperature is 61° or 620 F.

This association occupies about 9 percent of the survey area. Hambright soils make up about 45 percent of the association, Igneous rock land about 20 percent, and Gilroy soils about 15 percent. Cibo soils and Gullied land make up the remaining 20 percent

Hambright soils are well drained and are less than 20 inches deep. They have a surface layer of brown, medium acid heavy loam and a subsoil of brown , medium acid and neutral clay loam and stony clay loam. They are underlain by hard volcanic rock. Rock outcrop covers 2 to 25 percent of the area.

Igneous rock land has variable drainage. It has a thin mantle of relatively stable soil material. Rock outcrop covers 23 percent of the area. This land type is typically barren or has only sparse brush cover.

Gilroy soils are well drained and are 21 to 40 inches deep. They have a surface layer of dark grayish-brown, medium acid clay loam and a subsoil of brown, medium acid clay loam. They are underlain bybasic igneous rock. Rock outcrop covers 10 to 25 percent of some areas.

The soils of this association are used primarily for watershed and for range. The lesser slopes are used for lemons, for field crops, and for urban development.