Soil Series Descriptions So Il Type Rating

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SOIL SERIES DESCRIPTIONS and SO IL TYPE RATING

Page General Discussion - - l and 2 Symbols - Soil Inventory Chart - - 3 Storie Index Rating - - - - - 4 and 5 • Information on Each So ii Series. - 6 ff

Lloyd N. Brown Extension Soils Specialist December 1954

UNIVERSITY OF CALIFORNIA • BERKELEY page 1

SOIL SERIES DESCRIPTIONS AND SOIL TYPE RA TING

Members of the Agricultural Extension Service will find it helpful to have definite informa tion about the soil series with which they are working. To meet this need, the following infor mation has been prepared: • Pages 1. General Discussion ...•...... ••.••...•...... 1-2 2. Symbols - Soil Inventory Chart ...... 3 3. Storie Index Rating ...... 4-5 4. Information on each soil series

This is a companion publication to be used with "Soil Series of California" by Storie and Weir, which you were advised to purchase, and ''Basic Soil Surveys", which you have. This publica• tion and ''Basic Soil Surveys" have been punched for inclusion in a binder.

Each of the above four parts are discussed below:

1. General Discussion: This is che part that you are now reading.

2. Symbols - Soil Inventory Chart (Page 19c - Basic Soil Surveys): These are the symbols in the 10 columns under "CHARACTERISTICS". They are determined by soil surveyors in field work. They are later transferred to the Soil Inventory Chart. These charts are part of the llxl 7 soil survey reports published by the University of California on the recent soil surveys. Charts are being prepared for county use, as fast as time permits, covering the older 6x9 Soil Surveys containing the folded maps, with which you are familiar.

3. Storie Index Rating: This method of rating gives a definite percentage value to each soil type, such as Yolo sandy loam, Yolo fine sandy loam, Yolo loam, etc. This information is given in the last 5 columns on the Soil Inventory Charts described above. • 4. Information on each soil series is given on an accompanying single sheet of paper. Such a sheet will be prepared for each soil series and will consist of three parts:

The front side is devoted to a soil series description which has been derived from three main sources: a. The official soil series description prepared by the Soil Survey Group of the United States Department of Agriculture. b. The soil series description in their published reports which contain the folded maps. c. The series description in the llxl 7 reports published by the Department of Soils, University of California.

The reverse side has two tables: a. The upper table gives the soil series characteristics as given in the first 10 columns of the Soil Inventory Charts described above. b. The lower table gives a Storie Index Hating or Soil Rating for the soil types. This rating is made on A, B, C, and six X fac tors. The A, B, and C factors are always rated, but only as many of the six X factors as apply to a soil type are rated.

The Storie Index Rating is based on soil characteristics that govern a soil's potential utilization and productive capacity. It is wholly independen t of such factors as climate, availability of • irrigation water, accessibility, nearness to markets, etc. page 2

The older soil surveys were quite simple compared to those being made today, be cause of the technical progress in soil surveyin g methods. Consequently a new survey may divide an old soil series into several new ones. These new series are set up to show • a new soil with characteristics principally of agricultural significance. fhis trend in sep arating out new series will continue indefinitely, but at a slower rate. Consequently the preparation of the Soil Inven tory Charts for the older surveys is a rather difficult job. It will probably take consid erable help on the part of the specialist to make this information readily usable by county people.

The information on each soil series referred to under 4 in the first paragraph will be developed as rapidly as possible. Then each coun ty will be given this information on the series in that county along with pages 1 to 5 inclusive. This will make a permanent soils file for each county. It is probable that this distr ibution will be made at the time soil monoliths are made for a county~ or when a soils school is held in a county. It is also probable that some individuals may want a similar file.

Two words are used frequently in the '' soil series descriptions" which should be thoroughly understood - related and associated . Related soils are those which have some common characteristic such as being derived from the same parent material, belonging to the same profile group, etc. Hanford, Greenfield, Ramona, Placentia, and San Joaquin are secondary soils from granitic alluvium and hence related. Similarly, San Joaquin, Madera, and Redding are all group V. hardpan soils; and Holland, Sheridan, Sierra, Fall brook, and Vista are all primary soils found in place on granite. Associated soils are those which are geographically next to or near anoth er. They are frequently found on two adjoining terraces which have been laid down by streams originating in different • parent material, such as San Joaquin, from coarse-textured granitic sources, and Stock- ton, from fine-textured basic igneous sources. In areas of primary soils, the different underlying rocks produce different soils . Hence, on the contact between granite and basalt, you might have Holland and Aiken respectively. On these contacts between different rocks, there frequently is quite a wide zone of blocks of each of the different rocks which give rise to a compli cated pattern of soils. Such an area would be mapped as a soil £Q[!P.lex - hence a Holland-Aiken complex, a Contra Costa-Altamont complex, etc.

It is not the purpose of soil surveys to becom e involved in problems of soil man agement such as cultivation, alkali reclamation, and fertility.

This is a new undertak ing of considerable magnitude. Your suggestions are invited and your patience solicited .

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SOIL-RATI G CHART

(Storie Soil Index rating = factor A x facto r B x factor C x factor X)

FACTOR C--Rating on basis of slope FACTOR X--Rating of condition other than those in • factors A, B, and C per cent per cent A - Nearly level (0 to 2%) ...... 100 Drainage: AA - Gently undulating (0 to 2%) •••• •••• ••••• •• 9 5-100 well•drained...... 100 fairly well drained...... B - Gently sloping (3 to 8%) ...... 9 5-1 00 80-90 moderately waterlogged...... 40-80 BB - Undulating (3 to 8%) ...•.•...•.•...•...... 8 5-1 00 badly waterlogged...... l 0-40 C - Moderately sloping (9 to 15%) .•.•.•...... 80-95 subject to overflow ••••••••••••••••••••.•.•••••.••••• variable CC - Rolling (9 to 15%) •..••.••.••....•...•..•...• 80-95 Alkali: D - Strongly sloping (16 to 30%) .•...... • 70-80 alkali-free ••••••••••.•••••••••••••••••••.••.•••••••••••• 1 oc DD - Hilly (16 to 30%) ••..••...... •..•.. 70-80 slightly affected ...... 60-95 E - Steep (30 to 45%) •••••••.•••••.••...... •.. .•• 30-50 moderately affected •••••••••.•••••••••.••.••••••.•••• 30-60 F - Very steep (45% and over) ••.•••••..••.• ••• 5-30 moderately to strongly affected ...... 15-30 strongly affected •••••••...•••.••••••••.••••••••••.••• 5-15

Nutrient (fertility) level: high ••••••••••••••••••••••••••••.••••.••••••••.••••.•••••• l 00 fair •.••.••••••••••••••••••.••••••••••••••••••••••••.•••••• 95-100 poor ...... 80-95 very poor ...... 60-80

Acidity: according to degree •••••••••••••••••••.•••.••• 80-95

Erosion: none to slight ...... 100 detri men ta I deposition ••••••••••••• •••••••••••••••.•• 75-95 moderate sheet erosion ...... 80-95 occasional shallow gullies ••••••••••••••••.•••••••• 70-90 moderate sheet erosion with shallow gullies ••• 60-80 deep gullies ...... l 0-70 moderate sheet erosion with deep gullies •••••• 10-60 severe sheet erosion ...... 50-80 severe sheet erosion with shallow ~ullies .••••• 40-50 severe sheet erosion with deep gullies •••••••••• l 0-40 very severe erosion ••••••••••••••••••••••••••••.•••••• l 0-40 moderate wind erosion ...... 80-95 • severe wind erosion ...... 30-80 M icrore I ief: smooth ...... l 00 channels ...... 60-95 hogwallows ...... 60-95 low hummocks ••••••••••••••••••••••••••••.•.•••••••.••• 80-95 high hummocks •••••••••••••••••••..•••••••••••••••••••• 20-60 dunes ••••••••..••••••••••••••••••••••••••••••••.•••••.•••• 10-40

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