Bryan D. Furman, soil conservationist, Dennis Moore, agronomist, and Roy Bowman, soil scientist, Natural Resources Conservation Service, helped prepare this section.

General management needed for crops and for hay and pasture is suggested in this section. The crops or pasture plants are identified, and the system of land capability classification used by the Natural Resources Conservation Service is explained.

Planners of management systems for individual fields or farms should consider the detailed information given in the description of each soil under the heading "Detailed Soil Map Units." Specific information can be obtained from the local office of the Natural Resources Conservation Service or the Cooperative Extension Service.

Of the 1,042,400 acres in the survey area, 2.7 percent, or about 28,000 acres, is used for crops and pasture. The cropland is mostly in Anderson Valley and on the coastal terraces from Albion to just south of Point Arena.

The soils in western Mendocino County have characteristics that affect their behavior and that require specific management practices for various uses. Using the best management practices for each soil can improve or maintain productivity.

Erosion is a management concern on the more steeply sloping soils in the survey area. Practices that help to control erosion include conservation tillage; cover crops; storm runoff management; and critical-area planting on sites for road cuts, fills, pond embankments, and stream corridors.

The climate in the survey area strongly influences the crops that can be grown. Crops that can tolerate low temperatures are needed along the coast. Varietal wine grapes, apples, and pears are the major crops in Anderson Valley. Many of the alluvial soils in Anderson Valley, such as Boontling, Feliz, and Pinole soils, are suited to grapes and apples. Bearwallow soils are also suited to grapes. Anderson Valley grapes are considered premium wine grapes and receive some of the top prices in the industry. About 1,000 acres in the survey area is used for growing wine grapes, and the acreage has been steadily increasing.

Cover crops, irrigation water management, frost protection, and surface runoff management systems are generally needed on nearly level to moderately sloping soils used for vineyards and orchards. In some cases, subsurface drains are needed on the Boontling soils, which are susceptible to compaction by equipment or by livestock during wet periods.

Cover crops and surface runoff control systems, such as terraces, diversions, underground outlets, and grassed waterways, are needed in the more sloping vineyards and orchards to prevent sheet, rill, gully, and landslide erosion. Trickle irrigation systems are commonly used to start vines and may be needed after vines are established, depending on grape variety, soil properties, annual precipitation, and aspect.

Annual cover crops are grown in areas where trickle irrigation is used for grapes, where dryland grapes are grown, or where vineyards are disked or mowed. New winter annuals are usually seeded before October 15. Growth that occurs during the fall and winter months protects the vineyard from sheet and rill erosion. In early spring, before about April 1, mowing the cover crop to a height of 3 or more inches helps to minimize possible frost damage. After the seed has matured, the cover crop can be mowed to any height. The seed will then be available the following fall to start the annual growth cycle again.

Perennial cover crops are used in irrigated orchards and vineyards. They serve erosion-control functions similar to those of annuals but have other important characteristics. Perennial cover crops are mowed in the spring, thereby minimizing the hazard of frost damage, and are mowed through the summer as necessary. Perennial cover crops can compete for moisture and nutrients, but they may help to remove moisture from wet soils. In some cases, a drainage system may still be needed.

Late spring frosts are a management concern for grape producers. Frost protection is needed for many vineyards. Although several methods are used, overhead sprinklers are the major method of protection. The sprayed water encases young buds in ice and prevents them from freezing and being destroyed. The entire vineyard acreage must be protected at one time. The water requirement is 50 gallons per acre per minute. This large volume of water is commonly stored in on-farm reservoirs that are filled by winter runoff. Frost protection may not be necessary on hillside vineyards.

Irrigation is usually needed through the dry summer to maximize production from most crops. Most growers use wells or pump from streams. Sprinkler and trickle irrigation systems are the most common methods for irrigating fruit and pasture crops.

The cool, moist coastal terrace soils have historically been used to produce berries, bulbs, potatoes, peas, and other field and truck crops. Recently, there has been a resurgence in interest in the production of these crops. A few growers are producing cool-season vegetables for local markets. Hay, pasture, and silage are important crops for the dairy industry along the coast.

Pasture management is needed on irrigated pastures to maintain soil tilth, achieve maximum production, maintain a desirable species composition, and extend the life of the pasture. Practices needed in a pasture management program include irrigation water management, rotation grazing, fertilization, harrowing or dragging to scatter droppings, and mowing when necessary to maintain uniform growth. Grazing should begin when plants are 8 to 10 inches high and should end when 3 to 4 inches of stubble remains.

The average yields per acre that can be expected of the principal crops under a high level of management are given in the map unit descriptions. In any given year, yields may be higher or lower than those indicated because of variations in rainfall, other climatic factors, and management.

The yields are based mainly on the experience and records of farmers, conservationists, and extension agents. Available yield data from nearby counties and results of field trials and demonstrations are also considered.

The management needed to obtain the indicated yields of the various crops depends on the kind of soil and the crop. Management can include drainage, erosion control, and protection from flooding; the proper planting and seeding rates; suitable high-yielding crop varieties; appropriate and timely tillage; control of weeds, plant diseases, and harmful insects; favorable soil reaction and optimum levels of nitrogen, phosphorus, potassium, and trace elements for each crop; effective use of crop residue, barnyard manure, and green-manure crops; and harvesting that ensures the smallest possible loss.

For yields of irrigated crops, it is assumed that the irrigation system is adapted to the soils and to the crops grown, that good-quality irrigation water is uniformly applied as needed, and that tillage is kept to a minimum.

The estimated yields reflect the productive capacity of each soil for each of the principal crops. Yields are likely to increase as new production technology is developed. The productivity of a given soil compared with that of other soils, however, is not likely to change.

Yields for wine grapes are an average of high- and moderate-producing red and white varietal grapes. High-producing white grapes yield about 0.6 ton more than average, and moderate-producing white grapes yield about 0.2 ton less than average. High-producing red grapes yield about 0.2 ton more than average, and moderate-producing red grapes yield about 0.6 ton less than average.

Crops other than those listed in the map unit descriptions are grown in the survey area, but estimated yields are not given because the acreage of such crops is small. The local office of the Natural Resources Conservation Service or of the Cooperative Extension Service can provide information about the management and productivity of the soils for those crops.

Land capability classification shows, in a general way, the suitability of soils for most kinds of field crops. Crops that require special management are excluded. The soils are grouped according to their limitations for field crops, the risk of damage if they are used for crops, and the way they respond to management. The criteria used in grouping the soils do not take into account major and generally expensive landforming that would change slope, depth, or other characteristics of the soils, nor do they include possible but unlikely major reclamation projects. Capability classification is not a substitute for interpretations designed to show suitability and limitations of groups of soils for rangeland, for woodland, or for engineering purposes.

In the capability system, soils generally are grouped at three levels—capability class, subclass, and unit (USDA, 1961). These levels are defined in the following paragraphs.

Capability classes, the broadest groups, are designated by Roman numerals I through VIII. The numerals indicate progressively greater limitations and narrower choices for practical use. The classes are defined as follows:

Class I soils have few limitations that restrict their use.

Class II soils have moderate limitations that reduce the choice of plants or that require moderate conservation practices.

Class III soils have severe limitations that reduce the choice of plants or that require special conservation practices, or both.

Class IV soils have very severe limitations that reduce the choice of plants or that require very careful management, or both.

Class V soils are not likely to erode but have other limitations, impractical to remove, that limit their use.

Class VI soils have severe limitations that make them generally unsuitable for cultivation. Rangeland or forestry improvements can be applied.

Class VII soils have very severe limitations that make them unsuitable for cultivation. They can be used for forestry or grazing, but rangeland improvements are impractical.

Class VIII soils and miscellaneous areas have limitations that nearly preclude their use for commercial crop production.

Capability subclasses are soil groups within one class. They are designated by adding a small letter, e, w, s, or c, to the class numeral, for example, IIe. The letter e shows that the main hazard is the risk of erosion unless close-growing plant cover is maintained; w shows that water in or on the soil interferes with plant growth or cultivation (in some soils the wetness can be partly corrected by artificial drainage); s shows that the soil is limited mainly because it is shallow, droughty, or stony; and c, used in only some parts of the United States, shows that the chief limitation is climate that is very cold or very dry.

In class I there are no subclasses because the soils of this class have few limitations. Class V contains only the subclasses indicated by w, s, or c because the soils in class V are subject to little or no erosion. They have other limitations that restrict their use to pasture, rangeland, woodland, wildlife habitat, or recreation.

Capability units are soil groups within a subclass. The soils in a capability unit are enough alike to be suited to the same crops and pasture plants, to require similar management, and to have similar productivity. Capability units generally are designated by adding an Arabic numeral to the subclass symbol, for example, IIe-4 and IVw-2.

The capability classification of each map unit is given in table 3 and at the end of each map unit description in the section "Detailed Soil Map Units." The numbers used to designate units within the subclasses are as follows:

0.  Indicates limitations caused by stony, cobbly, or gravelly material in the substratum.

1.  Indicates limitations caused by slope or by an actual or potential erosion hazard.

2.  Indicates a limitation of wetness caused by poor drainage or flooding.

3.  Indicates a limitation of slow or very slow permeability in the subsoil or substratum.

4.  Indicates limitations caused by sandy or gravelly soils that have a low available water-holding capacity.

5.  Indicates limitations caused by a fine textured or very fine textured surface layer.

6.  Indicates limitations caused by salt or alkali.

7.  Indicates limitations caused by rocks, stones, or cobblestones.

8.  Indicates that the soil has a low or very low water-holding capacity because the root zone generally is less than 40 inches deep over massive bedrock.

9.  Indicates limitations caused by low or very low fertility, acidity, or toxicity that cannot be corrected by adding normal amounts of fertilizer or lime or by other measures.

Land capability classification is further refined by designating the major land resource area (MLRA) of the soils. A major land resource area is a broad geographic area that has a distinct combination of climate, topography, vegetation, land use and management, and soils (USDA, 1981). Parts of four of these nationally designated areas are in the survey area. These areas and their numbers are California Coastal Redwood Belt, MLRA 4; Siskiyou-Trinity Area, MLRA 5; Central California Coastal Valleys, MLRA 14; and Central California Coast Range, MLRA 15. The major land resource area number is added in parentheses after the land capability class, subclass, or unit designation at the end of each map unit description in the section "Detailed Soil Map Units."

MLRA 4, the California Coastal Redwood Belt. In this land resource area, the climate is tempered by cool marine air. The landscape is dominated by strongly sloping to very steep hills and mountains and has nearly level to steep marine terraces along the coast. The natural vegetation is mainly redwood and Douglas-fir. Elevation ranges from sea level to 2,500 feet. The average annual precipitation ranges from 35 to 80 inches. The average annual temperature is about 53 degrees F, and the average frost-free season ranges from 220 to 365 days. The summers are cool and moist with frequent fog. Abundant rainfall during the winter and numerous perennial streams provide enough water for most requirements.

Most of this land resource area is used for timber production. The marine terraces are also used for livestock grazing, hay production, pasture, or homesite development.

MLRA 5, Siskiyou-Trinity Area. This land resource area consists of the timbered mountainous land outside the influence of the marine climate. The landscape is dominated by strongly sloping to very steep hills and mountains. The natural vegetation is mainly Douglas-fir and tanoak. Elevation ranges from 500 to 4,235 feet. The average annual precipitation ranges from 40 to 80 inches. The average annual temperature is about 55 degrees F, and the average frost-free season ranges from 150 to 270 days. Most of the rainfall occurs during the winter. The summers are hot and dry, and rivers carry a low volume of water during this season.

Most of this land resource area is used for timber or firewood production.

MLRA 14, Central California Coastal Valleys. This land resource area includes the small inland valleys of the survey area—the Anderson, Laytonville, and Comptche valleys. The landscape is dominated by nearly level to moderately steep stream terraces and flood plains. In uncultivated areas, the natural vegetation is annual grasses and forbs. Elevation ranges from 160 to 2,200 feet. The average annual precipitation ranges from 40 to 60 inches. The average annual temperature is about 55 degrees F, and the average frost-free season ranges from 150 to 250 days. Most of the rainfall occurs during the winter. The summers are hot and dry, and irrigation is needed for most crops.

Most of this land resource area is used for livestock grazing, hay production, pasture, orchards, or vineyards.

MLRA 15, the Central California Coast Range. This land resource area consists of open grassland and oak-grass woodland. The landscape is dominated by moderately sloping to very steep hills and mountains. Elevation ranges from 300 to 4,000 feet. The average annual precipitation ranges from 45 to 70 inches. The average annual temperature is about 57 degrees F, and the average frost-free season ranges from 150 to 250 days. The summers are hot and dry, and most of the rainfall occurs during the winter.

Most of this land resource area is used for livestock grazing or firewood production.