Sumber: STELA – April 2013
SISR: STORIE INDEX SOIL RATINGS
Indeks Storie merupakan metode penilaian (rating)
tanah berdasarkan karakteristik tanah yang
menentukan potensi pemanfaatan tanah dan
kapasitas produktivitas tanah.
Metode ini tidak memperhitungkan faktor fisikj
lainnya atau faktor ekonomi yg mungkin
mempengaruhi kesesuaian tanaman di suatu lokasi.
Analisisnya mudah dilakukan, berbagai kategori
dikelompokkan menjadi beberapa kategori saja.
SISR: STORIE INDEX Soil Ratings
Ada empat atau lima parameter yg lazim dievaluasi:
A: Kedalaman Tanah dan Tekstur;
B: Permeabilitas Tanah;
C: Sifat Kimia Tanah;
D: Drainage, Limpasan permukaan;
E: Iklim (only if it is not homogeneous, if so than it should not be
included in the formula);
Indeks dihitung dengan perkalian parameter ini, yaitu:
Sindex = A x B x C x D x E
Kerugian /kelemahan metode ini adalah kalau kita mempunyai nilai
nol untuk suatu kategori, maka hasilnya akan nol dan tanah dianggap
tidak sesuai untuk penggunaan.
SISR: STORIE INDEX Soil Ratings
SISTEM PENILAIAN INDEKS STORIE
Sistem ini me-Ranking karakteristik tanah menurut kesesuaiannya
untuk pertanian, dari tanah-tanah Grade 1 (nilai 80 - 100), yg tidak
mempunyai pembatas untuk produksi pertanian hingga Tanah-tanah
Grade 6 ( nilainya kurang dari 10), yang tidak cocok untuk pertanian.
Under this system, soils deemed less than prime can function as prime
soils when limitations such as poor drainage, slopes, or soil nutrient
deficiencies are partially or entirely removed.
The six grades, ranges in index rating, and definition of the grades, as
defined by the NRCS, are provided below in Table 3.9, Storie Index
Rating System.
Sumber:
SISR: STORIE INDEX Soil Ratings
Indesk Storie merupakan metode semi-kuantitatif penilaian
tanah yg dapat digunakan untuk pertanian irigasi
berdasarkan data produktivitas tanaman yang dikumpulkan
dari survei tanah (Storie 1932; Reganold and Singer 1979).
Indeks Storie menduga produktivitas tanah berdasarkan
empat karakteristik berikut:
1.
2.
3.
4.
Factor A: Derajat perkembangan profil tanah;
Factor B: Tekstur lapisan permukaan;
Factor C: Slope;
Factor X: Kondisi lain tanah dan lahan, termasuk drainage,
alkalinity, fertility, acidity, erosion, dan microrelief.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf#page=7
SISR: STORIE INDEX Soil Ratings
Skor berkisar 0 - 100% ditentukan untuk setiap faktor, dan skor-skor ini
kemudian dikalikan satu-sama lain untuk mendapatkan Nilai Indeks
(Storie 1978).
One shortcoming of hand-generated Storie ratings is that the scoring
options for a particular factor or subfactor have broad and somewhat
arbitrary ranges, which creates a great potential for subjectivity among
scientists (O’Geen and Southard 2005).
Our goal was to develop a model in NASIS to rapidly generate Storie
ratings without inherent scoring discrepancies associated with handgenerated ratings.
Nilai Indeks Storie =
[(Factor A/100) × (Factor B/100) × (Factor C/100) × (Factor X/100)] ×
100
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf#page=7
REVISI SISR: STORIE INDEX Soil Ratings
Storie Index Rating System
Grade
Nilai Indeks
Definisi
1 – Excellent 80 – 100
Tanah-tanah sangat sesuai untuk penggunaan intensif
tanaman irigasi yang sesuai dnegan kondisi iklimnya.
2 – Good
60 - 79
Tanah-tanah sesuai untuk pertanian, although they may
not be so desirable as Grade 1 because of moderately
coarse, coarse, or gravelly surface soil texture; somewhat
less permeable subsoil; lower plant available water
holding capacity, fair fertility; less well drained conditions,
or slight to moderate flood hazards, all acting separately
or in combination.
3 – Fair
40 - 59
Tanah-tanah cukup sesuai untuk penggunaan pertanian
secara umum, and are limited in their use because of
moderate slopes; moderate soils depths; less permeable
subsoil; fine, moderately fine or gravelly surface soil
textures; poor drainage; moderate flood hazards; or fair to
poor fertility levels, all acting alone or in combination.
Sumber:
REVISI SISR: STORIE INDEX Soil Ratings
Storie Index Rating System
Grade
Index
Rating
Definisi
4 – Poor
20 - 39
Tanah-tanah kurang sesuai. They are severely limited in their
agricultural potential because of shallow soil depths; less
permeable subsoil; steeper slope; or more clayey or gravelly
surface soil texture than Grade 3 soils, as well as poor drainage;
greater flood hazards; hummocky micro-relief; salinity; or poor
fertility levels, all acting alone or in combination.
5 – Very
Poor
10 - 19
Tanah-tanah secara aktual tidak sesuai untuk pertanian, jarang
diolah untuk pertanian, biasanya untuk range, pasture, atau
hutan.
6 – Nonagriculture
Kurang
dari 10
Soils are not suited for agriculture at all due to very severe
to extreme physical limitations, or because of urbanization.
Source: USDA Soil Conservation Service, Soil Survey of Contra Costa County, 1977.
Sumber:
SISR: STORIE INDEX Soil Ratings
Semenjak 1980, negara bagian California telah melakukan pemetaan
lahan-lahan pertaniannya.
Program pemetaan lahan pertanian ini dilakukan secara terusmenerus dengan tingkat pemetaan yang semakin detail.
Kkriteria pemetaan lahan juga dimodifikasi terus menjadi semakin
detail.
Kriteria pemetaan lahan menggunakan sistem Indeks Storie dan sistem
SCS (konservasi tanah), tetapi juga mempertimbangkan kondisi fisik
seperti suplai air untuk produksi tanaman, soil temperature range,
depth of the ground water table, flooding potential, rock fragment
content and rooting depth.
Sumber:
SISR: STORIE INDEX Soil Ratings
Important Farmland Maps for California are compiled using the
modified LIM criteria (as described above) and current land use
information. The minimum mapping unit is 10 acres unless otherwise
specified.
Unit-unit lahan yng kurang dari 10 acre dimasukkan ke dalam
klasifikasi unit-lahan di sekitarnya. Peta lahan pertanian
mengidentifikasi tujuh kategori yg berhubungan dg pertanian: Prime
farmland, farmland of statewide importance (statewide farmland),
unique farmland, Lahan pertanian lainnya yg penting secara lokal.
Each is summarized below, based on A Guide to Farmland Mapping
and Monitoring Program (1998), prepared by the Department of
Conservation.
Sumber:
SISR: STORIE INDEX Soil Ratings
Arahan untuk pemetaan lahan pertanian yang disusun oleh
Departemen Konservasi USDA (1998).
Prime
Farmland:
Prime farmland is land with the best combination of physical and chemical
features able to sustain the long-term production of agricultural crops. This
land has the soil quality, growing season, and moisture supply needed to
produce sustained high yields. The land must have been used for the
production of irrigated crops at some time during the two update cycles (a
cycle is equivalent to 2 years) prior to the mapping date of 1998 (or since
1994).
Statewide
Farmland:
Farmland of Statewide Importance is land similar to prime farmland, but
with minor shortcomings, such as greater slopes or with less ability to hold
and store moisture. The land must have been used for the production or
irrigated crops at sometime during the two update cycles prior to the
mapping date (or since 1994).
Unique
Farmland:
Unique farmland is land of lesser quality soils used for the production of the
State’s leading agricultural crops. This land is usually irrigated, but may
include non-irrigated orchards or vineyards, as found in some climatic zones
in California. The land must have been cultivated at some time during the
two update cycles prior to the mapping date (or since 1994).
Sumber:
SISR: STORIE INDEX Soil Ratings
Arahan untuk pemetaan lahan pertanian yang disusun oleh
Departemen Konservasi USDA (1998).
Local
Farmland:
Farmland of local importance is land of importance to the local
agricultural economy, as determined by each county’s Board of
Supervisors and a local advisory committee. Contra Costa County
local farmland includes lands which do not qualify as Prime,
Statewide, or Unique designation, but are currently irrigated crops
or pasture or non-irrigated crops; lands that would meet the Prime
or Statewide designation and have been improved for irrigation, but
are now idle; and lands that currently support confined livestock,
poultry operations and aquaculture.
Grazing
Land:
Grazing land is land on which the existing vegetation, whether
grown naturally or through management, is suited to the grazing of
livestock. The minimum mapping unit for this category is 40 acres.
Sumber:
SISR: STORIE INDEX Soil Ratings
Arahan untuk pemetaan lahan pertanian yang disusun oleh
Departemen Konservasi USDA (1998).
Urban
Land:
Urban and built-up land is occupied with structures with a building
density of at least one unit to onehalf acre. Uses may include but
are not limited to, residential, industrial, commercial, construction,
institutional, public administration purposes, railroad yards,
cemeteries, airports, golf courses, sanitary landfills, sewage
treatment plants, water control structures, and other development
purposes. Highways, railroads, and other transportation facilities
are mapped as part of this unit, if they are part of a surrounding
urban area.
Other Land: Other land is land that is not included in any other mapping
categories. The following uses are generally included: rural
development, brush timber, government land, strip mines, borrow
pits, and a variety of other rural land uses.
Sumber:
SISR: STORIE INDEX Soil Ratings
R. Earl Storie is Professor Emeritus, Soils and Plant Nutrition and
former Soil Technologist in the Experiment Station, Berkeley.
INDEKS STORIE
Metode penilaian tanah ini, dikenal sebagai Indeks Storie,
berdasarkan atas karakteristik tanah yg mengendalikan
pemanfaatan lahan dan kapasitas produktif lahan.
It is independent of other physical or economic factors
that might determine the desirability of growing certain
plants in a given location.
Sumber:
SISR: STORIE INDEX Soil Ratings
Metode Storie yang telah direvisi menetapkan Faktor-C yang baru
untuk mengevaluasi slope; Faktor-C yang lama sekaranh dimasukkan
ke dalam Faktor-X.
Nilai-nilai persentase diberikan pada karakteristik tanah, termasuk
Profil Tanah (faktor A);
Tekstur tanah permukaan (faktor B);
Slope (faktor C);
Dan kondisi-kondisi yg eksklusif profil tanah, tekstur permukaan, dan
slope – misalnya drainage, kandungan alkali, kandungan hara,
erosion, dan micro relief (factor X).
Kondisi yang dianggap paling ideal (paling sesuai) untuk setiap faktor
diberi nilai 100%.
Nilai-nilai persentase dari empat faktor itu kemudian dikalikan
bersama untuk menghasilkan Nilai Indeks Storie dari tanah yang
dievaluasi.
Sumber:
SISR: STORIE INDEX Soil Ratings
Karakteristik profil tanah (faktor A) pada hakekatnya
merupakan ciri-ciri lapisan bawah permukaan.
Tanah di lokasi survei (mis. Di California) dikelompokkan menjadi
beberapa kelompok profil (mis. ada 9 kelompok profil tanah).
For example, soils that are deep and readily pervious to
roots and water (listed in profile group I in the soil-rating
chart) are rated at 100 percent.
Profil tanah dengan subsoil liat-padat (Kelompok Profil IV) diberi
nilai lebih rendah.
Primary or residual soils (listed in profile groups VII, VIII, and
IX) are rated in accordance with the depth to bedrock.
Sumber:
SISR: STORIE INDEX Soil Ratings
Tanah-tanah dinilai berdasarkan tekstur tanah lapisan
permukaan (Faktor B).
Medium- textured soils, such as the loams and the silt loams, are
rated highest;
the extremes in texture, such as sands and clays, lower.
Penilaian kemiringan lahan dimasukkan dalam Faktor C.
Nearly level or gently sloping land is rated at 100 per cent.
As the slope increases, the rating for this factor decreases.
As shown in the soil-rating chart, single letters are used to
indicate simple slopes , and double letters to indicate compound
slopes.
The percent slope expresses the number of feet rise or fall for
100 feet horizontal distance.
Sumber:
SISR: STORIE INDEX Soil Ratings
Kondisi eksklusif profil, tekstur tanah, dan slope
dimasukkan dalam Faktor X pada peta penilaian tanah.
These conditions consist of drainage, alkali or salt
content, general nutrient level, acidity, erosion, and
microrelief (surface regularity).
If two or more conditions exist that are listed under
factor X, the ratings for each are treated independently;
that is, they are multiplied in order to secure the factor
X rating.
Sumber:
SISR: STORIE INDEX Soil Ratings
SOIL - RATING CHART
(Storie Soil Index rating =
factor A x factor B x factor C x
factor X)
Sumber:
SISR: STORIE INDEX Soil Ratings
Faktor A: Kelompok Profil Tanah
Faktor A adalah nilai karakteristik profil tanah berdasarkan derajat
perkembangan tanah. Tanah-tanah dikelompokkan ke dalam
“Kelompok Profil” berdasarkan tipe landform dan perkembangan
horison genetiknya.
Soil development is defined as the presence of Bt horizons or
cemented layers.
Bt horizons are subsurface layers that have an increase in clay
relative to the overlaying horizons.
The increase is a result of the translocation of clay by percolating
water from overlaying soil horizons.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
SISR: STORIE INDEX Soil Ratings
Faktor A: Kelompok Profil Tanah
Untuk tanah-tanah alluvial, skor-nya semakin menurun dengan
semakin meningkatnya derajat perkembangan tanah, seperti yang
ditunjukkan oelh adanya horison Bt dan/atau adanya lapisan
penghambat pertumbuhan akar.
Misalnya, tanah-tanah aluvial yang solumnya dalam dan homogen
diberi nilai 100%, sedangkan tanah-tanah yang mempunyai horison
Bt pada landsekap-tua diberi nilai lebih rendah.
Soils with abrupt textural changes (claypan), duripan, or petrocalcic
horizons (hardpans) are rated lower still.
For soils derived from bedrock, scoring is based on depth to a lithic
(hard rock) or paralithic (soft rock) contact and the degree of soil
development in horizons overlying these layers (Storie 1932, 1978).
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
SISR: STORIE INDEX Soil Ratings
Faktor B: Tekstur Tanah Lapisan Permukaan
Faktor B berdasarkan tekstur tanah lapisan atas.
Tanah-tanah berlempung mempunyai nilai paling tinggi, dan
tanah-tanah liat tan tanah berpasir dinilai lebih rendah.
Rock fragment content is used to modify the scores, which
range from 100 to 10%.
The rating for Factor B can vary as much as 30% for a
specific textural class depending on the volume of coarse
fragments present (Storie 1932, 1978).
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
SISR: STORIE INDEX Soil Ratings
Faktor C: Slope
Faktor C berdasarkan pada kecuraman lereng. Lahan yang
hampir datar hingga sedikit miring (0 - 8% slope) diberi nilai
tinggi, berkisar 100 - 85%.
Moderate to strongly sloping conditions (9 to 30% slopes)
have scores ranging from 95 to 70%; slopes greater than
30% receive lower scores, ranging from 50 to 5% (Storie
1978).
Users choose a score in a somewhat subjective manner
based on these slope classes.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
SISR: STORIE INDEX Soil Ratings
Faktor X: Drainage, Alkalinity, Fertility,
Kemasaman, Erosi, dan Microrelief
Faktor X fokus pada sifat-sifat dinamis, kondisi tanah dan
landskap yg memerlukan pengelolaan secara khusus.
Characteristics considered are drainage class, alkalinity,
nutrient status, degree of acidity, wind and water erosion,
and microrelief. Scoring for each characteristic in Factor X is
subjective.
For example, drainage, erosion, and microrelief scores range from 100
to 10%, while fertility status and acidity scores range from 100 to 60
and 95 to 80%, respectively (Storie 1978)
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
PERKEMBANGAN MODEL
In our NASIS-based Storie Index, interpretation criteria were modeled
based on soil properties traditionally incorporated into the handgenerated Storie Index (1978).
The most closely related NASIS data elements that pertained to the
Storie 1978 criteria were used. Our model uses discrete and fuzzy
logic functions to obtain more precise scores for the factors associated
with the index.
Banyak kriteria baru dimasukkan ke dalam Model, dan faktor lainnya
dimodifikasi untuk menyesuaikan indeks dengan basis-data yang
tersedia.
Model Storie 1978 telah mengalami beberapa modifikasi dalam
penerapannya hingga saat ini.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
A system of interpretation generation using fuzzy logic was
included within the database structure during NASIS
development in order to develop more realistic soil
interpretations.
Our model uses fuzzy rule sets to more accurately score
Factors C and X. Discrete numerical scores in combination
with fuzzy logic functions were used for Factors A and B.
Gelisols, Histosols, Spodosols, Oxisols, Dan Andisols tidak
dapat dievaluasi, karena tanah-tanah ini tidak dikenal
dalam referensi Storie 1978.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Faktor A: Kelompok Profil Tanah
Banyaknya kelompok profil tanah untuk Faktor A diubah dari sembilan
kelompok dalam Storie 1978 menjadi empat kelompok.
Kelompok profil dalam Storie 1978 mengklasifikasikan tanah
berdasarkan derajat perkembanagannya dan sifat bahan induknya.
Dalam Model revisi ini ada penggabungan kelompokn profil tanah
yang kisaran skor-nya hampir sama.
Interpretive criteria implied in Storie Profile Group Factor A relied on
the current taxonomic placement (USDA NRCS 1999) of the soil in
NASIS. Thus, in some instances, out-of-date classifications needed to
be considered (table 1).
Variations on the profile group fuzzy rating curves (slope and shape)
that modify the effective rooting depth were devised to best match
the original scoring in Storie 1978.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Tahap pertama dalam pemodelan adalah
memilahkan tanah-tanah yang berkembang
dari batuan induk (Groups VI - IX) dari tanahtanah yg berkembang dari bahan aluvial
(Group I - V).
Landform type, a data field stored in NASIS,
was used for this initial classification.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Groups I to III of Storie 1978 were combined because they have a similar scoring
range and reflect subtle differences in soil development. These soils, which are
found on alluvial deposits, are scored based on the depth to root-restricting layers
such as shallow phases, consolidated material, gravel lenses, and stratified layers
with texture contrasts.
The scoring differences are identical in Groups I and II of Storie 1978 and are only
slightly lower in Group III. For these reasons they were combined in our model. The
soils of Groups I to III were identified through their classification.
Pada umumnya semua tanah-tanah Entisols, Inceptisols, Vertisols, Aridisols, Alfisols,
Mollisols, dan Ultisols yang tidak menunjukkan peningkatan kandungan liat secara
drastis dengan kedalaman atautidak mempunyai lapisan keras, dimasukkan dalam
Model.
A “more is better” fuzzy rating was applied to these profiles in reference to depth to
a restrictive layer. The curve reflects an optimal effective rooting depth where soil
thicknesses that exceed 100 centimeters received a maximum score of 100.
Skor-skor dikurangi berdasartkan kedalaman lapisan penghambat
pertumbuhan akar.
Index Storie yang diaplikasikan dalam Model NASIS
Mulai
Fans, terraces,
and flood plains
Factor A
Soil profile group
(see figure 2 and
table 1)
Landform
Uplands
X
Factor B
Surface texture
X
Groups I-III
Soil Orders: Entisols,
Vertisols, Aridisols,
Alfisols, Mollisols,
Ultisols, Inceptisols
Groups IV
Soil with
abrupt clay
increase:
“Pale”
Groups V
Soil with
cemented
layers:
Petrocalcic
Duripan
Scores determined by effective soil depth using fuzzy rule
Groups VII-IX
Soil depth:
Fuzzy rule “more is better”
Soil orders not rated:
Histosols, Gelisols, Spodosols,
Oxisols, and Andisols
Crisp limits for surface
textural class scores
(see table 2)
Fuzzy rule - “less is better”
for surface coarse
fragments
(see figure 3)
Index Storie yang diaplikasikan dalam Model NASIS
X
Fuzzy rule - “less is better”
Slope 0-100%
(see figure 4)
Factor C
Slope
X
Hydrology and
Physical properties
Factor X
Dynamic
properties
Growing
season
wetness “less
is better”
(see figure 6)
Flooding fuzzy rule
“less is
better”
(see figure 7
and table 5)
Erosion crisp
limits
(see table
4)
Drainage crisp limits
(see table
3)
X
EC fuzzy rule
“less is
better”
(see figure
5b)
Chemistry and
fertility
SAR fuzzy rule
“less is
better”
(see figure
5b)
pH fuzzy rule
“optimum
”
(see figure
5a)
Rivised SISR: STORIE INDEX Soil Ratings
Konsep awal tentang Profil Kelompok IV dalam Storie 1978 tetap
digunakan dalam Model ini.
Soils in this group are found on older plains and terraces and have dense, clay-rich
subsoils that restrict the movement of water and roots. Soils in this group were
identified in NASIS based on Soil Taxonomy (USDA NRCS 1999).
All soils with the formative element “pale” at the great group level were included. In
addition, Albaqualfs and Albaquults were included. The upper limit of the scoring
range for Profile Group IV in Storie 1978 was initially assigned, then modified by
effective soil depth.
Misalnya, tanah Palexeralf (tanah dengan lapisan cadas liat) dengan kedalaman
cadas liat kurang dari 1 foot semestinya akan mendapat nilai 85. Skor ini kemudian
direvisi berdasarkan “kedalaman yang tepat” hingga horison (lapisan) penghambat
akar.
Hal ini menghasilkan skor Faktor A yang lebih rendah untuk tanah Palexeralf (~35)
berdasarkan tebalnya lapisan tanah di atas lapisan cadas liat.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Konsep original Kelompoik Profil V tetap dipertahankan dalam Model
ini. Tanah-tanah dalam kelompok ini ditemukan pada kipas dan terras
tua , dan mempunyai subsoil yang padat dan keras, sehingga
membatasi pergerakan air dan pertumbuhan akar.
Semua tanah dengan anasir formatif Duri, Petro, Fragi, Petra, dan
Plinth yang muncul pada tingkat great-group juga dimasukkan dalam
model. Semua tanah Durids yg diklasifikasikan pada tingkat suborder
dan tanah-tanah Duric atau Petrogypsic pada tingkat subgroup juga
dimasukkan dalam Model.
The upper limit of the scoring range for Profile Group V in Storie 1978
was initially assigned.
A fuzzy logic rule “more is better,” in reference to depth to the
cemented pan, was then used to revise the upper limit of the score
based on the exact depth (the representative value for depth in
NASIS) to the restrictive horizon.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Formative elements of restrictive horizons are not used at
the great group level in Soil Taxonomy (1999) where the
upper boundary of the layer is greater than 1 meter below
the surface. In such cases, the depth to these layers is
populated in NASIS as a component restriction in the
database.
A “flag” was placed in the model so that when the
component restriction attribute is populated the soil is
placed in its appropriate profile group and scored
accordingly.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Group VI dalam sistem Storie 1978 dihilangkan karena
kesamaannya dengan Group IV.
Group VII hingga IX dalam Storie 1978 digabungkan karena
mereka mempunyai kesamaan kisaran skor berdasarkan
kedalaman perakaran. Kelompok ini mencerminkan tanahtanah dengan bahan induk residuum dan colluvium.
The fuzzy logic rule “more is better,” in reference to depth
to lithic or paralithic contact, was used to modify the score
based on the rooting depth.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Faktor B: Tekstur lapisan permukaan
Nilai-nilai Crisp ditetapkan untuk kelas tekstur tanah lapisan
permukaan sesuai dengan Storie 1978 (Table 2).
The following textures were not listed in Storie 1978: very
fine sandy loam, sandy clay, loamy coarse sand, loamy fine
sand, loamy very fine sand, and silt.
These missing textural classes were assigned ratings in our
model (Table 2). At the present time, the NASIS model does
not rank organic horizons.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Faktor B: Tekstur lapisan permukaan
Semua skor kelas tekstur tanah dimodifikasi berdasarkan
kandungannya fragmen batuan dengan menerapkan aturan logikafuzzy “less is better”.
The slope of line segments differed based on three coarse fragment
volume classes: less than 15%, 15 to 35%, and greater than or equal to
35%.
The fuzzy score for rock fragment content was then used to weight the
surface soil textural class score for Factor B.
For example, a silt loam with 5% rock fragments received a score of
100%, while a very gravelly silt loam with 40% rock fragments
received a score of approximately 60%, that is, it was weighted
proportionally to the volume of coarse fragments present.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Faktor C: Slope
The scoring threshold values for slope classes established in Storie
1978 were used to append the fuzzy logic rule “less is better” to
produce a unique score for any representative value of slope stored in
NASIS.
Fungsi ini mengurangi subyektivitas yg berhubungan dengan pemilihan
suatu skor dari kisaran skor-skor di dalam setiap faktor.
Misalnya dalam Storie 1978 :
Faktor C (slope) mempunyai kategori slope dengan skor yang berkisar
dari 100% (“nearly level”) hingga 5% (“very steep”).
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Faktor X: Sifat-sifat yang Dinamik
Data elements stored in NASIS that pertain to Factor X (renamed “Dynamic
Properties” in our model) were combined into two groups: chemical and fertility
properties (Xcf); and hydrologic and physical conditions (Xhp).
Soil chemical and fertility limitations were established for pH, electrical conductivity
(EC), and sodium adsorption ratio (SAR).
Hydrologic and physical conditions were assessed using drainage class, flooding
frequency, flooding duration during the growing season, saturated conditions during
the growing season, and erosion class. The Factor X score was calculated as the
product of the lowest score in each subfactor group (Xcf and Xhp).
Dalam Model ini, hanya digunakan dua sifat dinamis yang paling membatasi untuk
perhitungan Faktor X.
Xcf x Xhp = Faktor X
dimana:
Xcf : Skor terendah dari subfaktor kimia dan kesuburan
Xhp : Skor terendah subfaktor kondisi hydrologis dan fisika.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Kondisi kimiawi pada Faktor X yang telah direvisi agak berbeda
dengan faktor X dalam Storie 1978.
In order to obtain more quantitative indices for chemical
conditions in soil, thresholds in toxicity or osmotic effects were
established for electrical conductivity (EC) and pH to reflect
conditions that adversely affect plant growth, as well as for sodium
adsorption ratio (SAR) to reflect conditions that affect soil
dispersion and water movement.
Tanah-tanah mendapatkan nilai 100% hingga tercapai tingkat suboptimal.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Fuzzy rule sets were implemented in NASIS to model the magnitude of
the impairment.
For example, an optimal curve was used to score pH through a
trapezoidal pH optimal curve reflecting extremes in alkalinity and
acidity. Scores of 100% were given to pH values ranging from 5.5 to
8.5.
A “less is better” curve was used to score SAR and EC.
Scores begin to decrease with SAR values that exceed 7.
Soil Taxonomy (1999) uses SAR greater than or equal to 13 to indicate
Na-affected soils, but other research has shown that soil water
movement can be affected by Na dispersion at SAR as low as 5
(Shainberg et al. 1981).
Scores begin to decrease when EC is greater than 1 and then decrease
sharply when the threshold for saline soils (EC ≥ 4 dSm-1 ) is
surpassed (Regional Salinity Laboratory Staff 1954).
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Crisp scores were assigned to certain soil physical properties because
many are interpretations reported as classes rather than measured
continuous variables. Scores for drainage class and erosion class were
derived using crisp values (Tables 3 and 4).
Scores for a particular erosion class were higher for uplands because
slope is a component of the erosion class. Also, because slope was
already considered in Factor C, these scores were adjusted to avoid
penalizing the site twice for the same condition.
Uplands versus lowlands were identified in NASIS based on landform
type and scored separately.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Tanah jenuh air, frekuensi banjir, dan durasi banjir berpengaruh buruk terhadap
pertumbuhan tanaman kalau terjadi selama musim pertumbuhan tanaman.
Lamanya musim pertumbuhan ditentukan berdasarkan regim suhu tanah. Tanahtanah dnegan resim suhu cryic, pergelic, atau isofrigid mempunyai musim
pertumbuhan lebih pendek, July dan August.
Soils with frigid or mesic temperature regimes were given a growing a season from
May to September, while thermic temperature regimes were given a growing season
from March to October.
Isomesic and hyperthermic regimes were given growing seasons that extended 11
months of the year, from February through December.
Isothermic and isohyperthermic temperature regimes had year-round growing
seasons.
The minimum depth to saturated conditions encountered during the growing season
was derived from the fuzzy logic curve “more is better” (fig. 6).
Flooding (duration and frequency) was also assessed according to these defined
growing seasons.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
RIVISED SISR: STORIE INDEX SOIL RATINGS
Interpretasi survei tanah ttg kelas frekuensi banjir dan kelas durasi
banjir digunakan untuk mendeskripsikan dampak kejadian banjir yg
terjadi selama musim pertumbuhan tanaman.
Flooding frequency is an estimate of the number of flood events that
occur in a month. Flooding duration is the length of time flood waters
reside on a particular site. Scores were established for flooding
duration and frequency classes that are reported in NASIS.
The scores for a particular flooding duration class and flooding
frequency class were then multiplied to get a flooding frequency and
duration factor for the growing season.
Hubungan linear digunakan untuk merevisi skor bagi sub-faktor ini.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Keuntungan Pendekatan Pemodelan Indeks Storie
Indeks Storie yang direvisi mencerminkan penyempurnaan dari sistem
klasifikasi 1978.
Indeks yang dihitung dengan Model NASIS ini snagat cepat, tidak bias,
dan akurat untuk menilai potensi produktivitas lahan di daerah survei.
It is capable of generating hundreds of Storie ratings in seconds for
SSURGO II datasets.
The NASIS model is a data-driven tool that reduces the subjectivity of
the hand-generated Storie Index and improves the reliability of these
ratings, which may guide land use policy for the future.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Keuntungan Pendekatan Pemodelan Indeks Storie
Model ini berbeda dengan Storie 1978 karena beberapa sifat tanah
dan landskap disimpan dalam basis-data NASIS. Perubahan juga
dilakukan untuk meningkatkan objektivitas skoring.
For Factor A, profile groups were condensed from nine in Storie 1978
to four because the range in scores was similar in some groups (Profile
Groups I to III and VII to IX).
We also eliminated Profile Group VI in Storie 1978 because of its
similarity to Group IV.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX SOIL RATINGS
Keuntungan Pendekatan Modeling Indeks Storie
Modifikasi dilakukan pada Faktor X, yang disebut “Faktor Dinamik.”
Dalam Model Storie 1978 digunakan kondisi-alkali, tetapi dalamk
Model ini digunakan nilai-nilai EC dan SAR untuk mencerminkan
kondisi-kondisi saline, sodik, dan saline- sodik.
An assessment of nutrient status was not attempted in our model
because fertility can be a very dynamic property in agricultural
settings, depending on fertilization practices and other variables.
Flooding frequency and duration of saturation during the growing
season were added to Factor X because of their importance in
assessing land capability. Microrelief was not used in our model
because it is often not populated in NASIS (especially in older surveys)
and because land leveling has altered most agricultural land that once
contained microrelief
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Kurva rating linear untuk interaksi banjir, dihitung
fengan menggunakan skor frekuensi banjir dan skor
lamanya (durasi) banjir, sbb:
Flooding interaction =
(frequency class/100) x (duration
class/100).
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Table 5. Subfactor scores for Factor X, flooding frequency* and
duration during the growing season.
Note: Flooding frequency and duration classes are defined in the
National Soil Survey Handbook (USDA NRCS 2007).
Kelas Frekuensi Banjir Skor
None
very rare
Rare
Occasional
Frequent
very frequent
100
100
90
85
70
60
Kelas Durasi Banjir
None
extremely brief
very brief
brief
long
very long
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Skor
100
100
100
95
85
75
Rivised SISR: STORIE INDEX Soil Ratings
Figure 6.
“Optimal: more is better” fuzzy rating curve for
Factor X, depth to saturation during the growing
season.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Table 4.
Skor Subfaktor untuk Faktor X, Kelas Erosi.
(Erosion ratings were different for uplands versus lowlands
because slope is a dominant variable impacting erosion class
ratings in uplands.)
Kelas Erosi
0
1
2
3
4
Skore Lowland
100
80
60
40
20
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Skore Upland
100
95
85
75
65
Rivised SISR: STORIE INDEX Soil Ratings
Tabel 3. Skor Subfaktor untuk Faktor X, Kelas Drainage
Kelas Drainage
Skor
Excessively drained and
Somewhat excessively drained
Well drained
Moderately well drained
Somewhat poorly drained
Poorly drained and very poorly drained
85
100
90
70
50
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Table 1. Faktor A, penyebutan kelompok profil tanah melalui data taxonomi yg disimpan
dalam NASIS (Note: Landform type, a field stored in NASIS, was first used to separate alluvial
soils (Groups I to V) from upland soils (Groups VI to IX). Soil Taxonomy (USDA NRCS 1999) was
used to place the soil in one of four new groups. Histosols (peat soils), Gelisols (soils with
permafrost), Oxisols (highly weathered tropical soils), Andisols (volcanic soils), and Spodosols
(cool humid forest soils) were not rated.
Storie
1978
profile
group
Revised
profile
group
Taxonomic units queried
Concept notes and
query rules
I
1
Suborders:
Fluvents, Aquents, Psamments, Orthents, Xererts,
Torrerts, Usterts, Uderts
Soils of recent alluvial
deposits.
Query rules:
Must not have
restrictive horizons and
cannot
be on hillslopes or
mountains.
Great groups:
Haplaquolls, Aquisalids, Calciaquerts, Dystraquerts,
Epiaquerts
Endoaquerts, Natraquerts, Salaquerts
Subgroups:
Calcic Haplosalids, Gypsic Haplosalids, Typic
Haplosalids
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Table 1. Faktor A, penyebutan kelompok profil tanah melalui data
taxonomi yg disimpan dalam NASIS
Storie
1978
profile
group
Revised
profile
group
Taxonomic units queried
II
1
Suborders: Arents, Cambids
Concept notes and
query rules
Young soils on alluvial
deposits.
Great groups:
Query rules:
Haploxerolls, Haplustolls, Hapludolls, Vermustolls,
Cannot be on hillslopes
Calciustolls, Haprendolls, Calciudolls, Vermudolls,
or mountains. Outdated
Calciaquolls, Calcigypsids, Haplogypsids,
taxa included if updates
Haplocalcids, Sulfaquepts, Vermaquepts,
were not performed in
Endoaquepts, Epiaquepts, Humaquepts, Sulfudepts, NASIS. Presence of
Eutrudepts, Dystrudepts, Calciustepts, Dystrustepts, abrupt textural change
Haplustepts, Calcixerepts, Haploxerepts
included for stratified
soils and gravelly
Outdated taxa: Xerumbrepts and Xerochrepts
subsoils.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Table 1. Faktor A, penyebutan kelompok profil tanah melalui data taxonomi yg
disimpan dalam NASIS
Storie
1978
profile
group
Revised
profile
group
Taxonomic units queried
Concept notes and
query rules
III
1
Great groups:
Moderately welldeveloped soils
formed in older
alluvial deposits.
Query rules:
Cannot be on
hillslopes or
mountains. Presence
of abrupt textural
change included for
stratified soils and
gravelly subsoils.
Argigypsids, Natrigypsids, Natrargids, Gypsiargids, Calciargids,
Haplargids,
Vermaqualfs,
Epiaqualfs,
Endoaqualfs,
Glossaqualfs,
Kandiaqualfs,
Natraqualfs,
Hapudalfs,
Kandiudalfs,
Kanhapludalfs,
Natrudalfs,
Haplustalfs,
Rhodustalfs,
Natrustalfs,Natrixeralfs,
Rhodoxeralfs,
Haploxeralfs, Argialbolls, Natralbolls, Natraquolls, Argiaquolls,
Natrudolls, Argiudolls, Natrustolls, Argiustolls, Natrixerolls,
Argixerolls, Kandiaquults, Kanhaplaquults, Umbraquults,
Endoaquults, Epiaquults, Kandihumults, Kanhaplohumults,
Haplohumults, Kandiudults, Kanhapludults, Hapludults,
Rhodudults, Kandiustults, Kanhapustults, Rhodustults,
Haplustults, Haploxerults; also includes all “pale” great
groups and Albaqualfs and Albaquults that do not have an
abrupt clay increase with depth, but may have a thick argillic
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Table 1. Faktor A, penyebutan kelompok profil tanah melalui data taxonomi yg disimpan
dalam NASIS
Storie Revised Taxonomic units queried
1978
profile
profile group
group
Concept notes and
query rules
IV
Strongly developed
soils formed in old
alluvial deposits.
Query rules:
Cannot be on
hillslopes or
mountains.
2
Great groups:
All “pale” great groups of Aridisols,
Mollisols and Alfisols, and
Albaqualfs and Albaquults that also
have abrupt clay increase with depth
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Tabel 1. Faktor A, penyebutan kelompok profil tanah melalui data
taxonomi yg disimpan dalam NASIS
Storie Revised
1978
profile
profile group
group
Taxonomic units queried
Concept notes and
query rules
V
Suborder:
Durids
Soils with hardpans
formed in old alluvial
deposits.
3
Great groups:
Petro, Dur, Fragi, Petra, Plinth
Query rules:
Cannot be on hillslopes or
Subgroups:
mountains. Fuzzy rule
Duric Haplosalids, Petrogypsic Haplosalids depth to restrictive
horizon used to generate
Other:
score.
Calciudolls that have a petrocalcic horizon
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Table 1. Faktor A, penyebutan kelompok profil tanah melalui data
taxonomi yg disimpan dalam NASIS
Storie
1978
profile
group
Revised
profile
group
Taxonomic units queried
Concept notes and
query rules
VI
2
Not included
Group VI was dropped because
of its similarity to Group IV.
VII-IX
4
All colluvial and residual soils
formed on mountains and hillslopes
Groups VII to IX were combined
based on soil depth in Storie
1978 to bedrock or consolidated
material. Soils on upland areas.
Fuzzy rule depth to lithic or
paralithic contact used to
generate score.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Table 1. Faktor A, penyebutan kelompok profil tanah melalui data
taxonomi yg disimpan dalam NASIS
Storie
1978
profile
group
Revised
profile
group
I
1
Taxonomic units queried
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Concept notes and
query rules
Rivised SISR: STORIE INDEX Soil Ratings
Figure 2. Fuzzy logic rating functions “more is better” to define the
effective soil depth in Factor A, soil profile group.
A: A rating curve for Profile Groups I–III.
B: A rating curve for Profile Group IV describing the depth to an
abrupt texture change.
C: A rating curve for Profile Group V depth to a cemented pan.
D: A rating curve for Profile Groups VII–IX describing the depth to
bedrock
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Tabel 2. Skore penilaian “Crisp” untuk Faktor B, Kelas tekstur horison
permukaan
Kelas Tekstur Lap. Permukaan
Nilai
very fine sandy loam, fine sandy loam, loam, silt, silt loam
loamy very fine sand, sandy loam, sandy clay loam,
calcareous silty clay loam, clay loam
100
coarse sandy loam, loamy fine sand, noncalcareous silty clay loam, clay loam
90
loamy sand, very fine sand
fine sand, loamy coarse sand, sandy clay
80
65
Pasir, Liat Berdebu
60
Liat = Clay
50
Pasir Kasar
30
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
95
Rivised SISR: STORIE INDEX Soil Ratings
Figure 3.
“Less is better” fuzzy rating curve for Factor B,
surface rock fragment content.
Straight line segments represent three classes of
rock fragment volume percent populated in NASIS: 015, 15-35 and > 35.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Figure 4.
“Less is better” fuzzy rating curve for Factor C, slope.
Most soil scientists express slope gradient as a
percent, the difference in elevation between two
points as a percentage of the distance between
those points.
Slope 100% setara dengan sudut kemiringan 45°.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Figure 5A.
“Optimal” fuzzy rating curve for Factor X, pH,
in the surface layer.
Nilai pH optimal antara pH 5.5 dan 8.5.
Kondisi ekstrim terjadi pada nilai pH rendah.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Figure 5b.
“Optimal: less is better” fuzzy rating curve for Factor
X, surface soil sodium adsorption ratio.
Skore menjadi lebih rendah kalau nilai SAR lebih dari
7.
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
Rivised SISR: STORIE INDEX Soil Ratings
Figure 5C.
“Optimal: less is better” fuzzy rating curve for Factor
X, surface soil electrical conductivity (EC).
Skor menjadi lebih rendah kalau nilai EC melebihi
1.0
Sumber: http://anrcatalog.ucdavis.edu/pdf/8335.pdf
FAKTOR A. Penilaian Karakter Fisik Profil
I. Tanah-tanah pda kipas-aluvial muda, dataran banjir, atau
deposir sekunder lainnya yg belum berkembang
Profiles …………………….100 %
X - shallow phases (on consolidated material). 2 feet deep …… 50 - 60 %
X - shallow phases (on consolidated material). 3 feet deep …… 70 %
G - extremely gravelly subsoils …… 80 - 95 %
S - stratified clay subsoils ……. 80 - 95 %
II. Tanah-tanah pada Kipas-aluvial muda , dataran banjir.
or other secondary deposits having slightly developed profiles …… 95 - 100 %
X - shallow phases (on consolidated material). 2 feet deep ….. 50 - 60
X - shallow phases (on consolidated material). 3 feet deep ….. 70
G - extremely gravelly subsoils ….. 80 - 95
S - stratified clay subsoils ….. 80 - 95
Sumber:
SISR: STORIE INDEX Soil Ratings
III. Tanah-tanah pd kipas aluvial tua, dataran aluvial atau terras tua,
perkembangan profilnya moderat (subsoil agak rapat) ….. 80 - 95 %
X - shallow phases (on consolidated material). 2 feet deep ….. 40 - 60
X - shallow phases (on consolidated material). 3 feet deep ….. 60 - 70
G - extremely gravelly subsoils ….. 60 - 90
IV. Tanah-tanah pd dataran atau terras tua, profilnya sudah
berkembang (subsoil liat padat) ….. 40 - 80 %
V. Tanah-tanah pada Dataran atau Terras tua yg mempunyai subsoil
cadas-keras:
1. pada kedalaman kurang 1 foot …… 5 - 20
2.
3.
4.
5.
at 1
at 2
at 3
At 4
to
to
to
to
2
3
4
6
feet
feet
feet
feet
….. 20 - 30
….. 30 - 40
….. 40 - 50
….. 50 - 80
SISR: STORIE INDEX Soil Ratings
VI. Tanah-tanah pada terras tua dan lahan kering dengan
subsoil liat padat , bahan induknya material padu atau agak
padu ……. 40 - 80
VII. Tanah-tanah di lahan kering yang lapisan bawahnya
keras pada kedalaman:
1.
2.
3.
4.
5.
6.
at less than 1 foot ….. 10 - 30
at 1 to 2 feet ….. 30 - 50
at 2 to 3 feet ….. 50 - 70
at 3 to 4 feet ….. 70 - 80
At 4 to 6 feet ….. 80 - 100
at more than 6 feet …… 100
Sumber:
SISR: STORIE INDEX Soil Ratings
VIII. Tanah-tanah di lahan kering yang lapisan bawahnya
batuan sedimen
1.
2.
3.
4.
5.
6.
at less than 1 foot ….. 10 - 30
at 1 to 2 feet ….. 30 - 50
at 2 to 3 feet ….. 50 - 70
at 3 to 4 feet ….. 70 - 80
at 4 to 6 feet ….. 80 - 100
at more than 6 feet ….. 100
IX. Tanah-tanah di lahan kering yg lapisan bawahnya
material lunak
1.
2.
3.
4.
5.
6.
at less than 1 foot ….. 20-40
at 1 to 2 feet ….. 40 - 60
at 2 to 3 feet ….. 60 - 80
at 3 to 4 feet ….. 80 - 90
at 4 to 6 feet ….. 90 - 100
at more than 6 feet ….. 100
SISR: STORIE INDEX Soil Ratings
FAKTOR B --- Penilaian atas dasar tekstur lapisan permukaan
Tekstur Medium :
1.
2.
3.
4.
5.
6.
7.
8.
fine sandy loam ….. 100
loam ….. 100
silt loam ….. 100
Sandy loam …… 95
silty clay loam, calcareous ….. 95
Silty clay loam. noncalcareous ….. 90
clay loam. calcareous ….. 95
clay loam. noncalcareous ….. 85 - 90
Tekstur Berat atau Halus:
1.
2.
3.
4.
silty clay. highly calcareous ….. 70 - 90
silty clay. noncalcareous ….. 60 - 70
clay. Highly calcareous …….. 70 - 80
clay. noncalcareous ….. 50 - 70
Sumber:
SISR: STORIE INDEX Soil Ratings
Tekstur Ringan atau Kasar:
coarse sandy loam
Loamy sand
very fine sand
Fine sand
sand
Coarse sand
90
80
80
65
60
30-60
Berkerikil :
Lempung-berpasir-halus Berkerikil
70-80
Lempung Berkerikil
60-80
gravelly silt loam
60-80
gravelly sandy loam
50-70
gravelly clay loam
60-80
gravelly clay
40-70
Pasir Berkerikil
20-30
Sumber:
SISR: STORIE INDEX Soil Ratings
Penilaian Kondisi Berbatu:
Lempung-berpasir-halur Berbatu
70-80
Lempung Berbatu
60-80
stony silt loam
60-80
stony sandy loam
50-70
stony clay loam
60-80
stony clay
40-70
Pasir berbatu
10-40
Sumber:
SISR: STORIE INDEX Soil Ratings
Penilaian Fdaktor C atas dasar Slope
A - Nearly level (0 to 2%)
100
AA - Gently undulating (0 to 2%)
95-100
B-Gently sloping (3 to 8%)
95-100
BB-Undulating (3 to 8%)
85-100
C-Moderately sloping (9-15%)
80-95
CC-Rolling (9 to 15%)
80-95
D-Strongly sloping (16 to 30%)
70-80
DD-Hilly (16 to 30%)
70-80
E - Curam (Slope 30 - 45%)
30-50
F – Sangat Curam (45% dan lebih)
5-30
Sumber:
SISR: STORIE INDEX Soil Ratings
Penilaian Faktor X, selain faktor A, B dan C
Drainage:
well-drained
100
fairly well drained 1/
80-90
moderately waterlogged 2/
40-80
badly waterlogged 3/
10-40
subject to overflow
variable
Alkali: 4/
alkali-free
100
slightly affected
60-95
moderately affected
30-60
moderately to strongly
affected
15-30
strongly affected
Ketersediaan Hara (Tingkat
Kesuburan Tanah):
high
100
fair
95-100
poor
80-95
very poor
60-80
Acidity: according to
degree 5/
80-95
5-15
Sumber:
SISR: STORIE INDEX Soil Ratings
Penilaian Erosi Tanah:
Tidak ada erosi atau sedikit sekali
detrimental deposition
moderate sheet erosion
occasional shallow gullies
moderate sheet erosion with: shallow gullies
deep gullies
100
75-95
80-95
70-90
60-80
10-70
moderate sheet erosion with: deep gullies
10-60
severe sheet erosion
severe sheet erosion with: shallow gullies
Jurang-erosi dalam
Erosi sangat parah
Erosi angin moderat
Erosi angin parah
50-80
40-50
10-40
10-40
80-95
30-80
Sumber:
SISR: STORIE INDEX Soil Ratings
Microrelief:
Rata-halus: Smooth
100
Channels
60-95
hogwallows
60-95
low hummocks
80-95
high hummocks
20-60
dunes
10-40
Sumber:
SISR: STORIE INDEX Soil Ratings
PENENTUAN GRADE TANAH
Ada enam GRADE Tanah yang dideskripsikan menurut kisaran nilai indeks sbb:
1. Grade 1 (excellent): Soils that rate between 80 and 100 percent and which are
2.
3.
4.
5.
suitable for a wide range of crops, including alfalfa, orchard, truck, and field crops.
Grade 2 (good): Soils that rate between 60 and 79 percent and which are suitable for
most crops Yields are generally good to excellent.
Grade 3 (fair): Soils that rate between 40 to 59 percent and which are generally of fair
quality, with less wide range of suitability than grades 1 and 2 Soils in this grade may give
good results with certain specialized crops.
Grade 4 (poor): Soils that rate between 20 to 39 percent and which have a narrow range
in their agricultural possibilities For example, a few soils in this grade may be good for rice,
but not good for many other uses.
Grade 5 (very poor): Soils that rate between 10 and 19 percent are of very limited use
except for pasture, because of adverse conditions such as shallowness, roughness, and
alkali content.
6. Grade 6 (nonagricultural): Soils that rate less than 10 percent include, for
example, tidelands, riverwash, soils of high alkali content, and steep broken land.
SISR: STORIE INDEX Soil Ratings
Current terminology:
1/ moderately well drained
2/ somewhat poorly drained
3/ poorly to very poorly drained
4/ salinity/sodicity
5/ pH less than 50
Sumber:
SISR: STORIE INDEX Soil Ratings
Tanah-tanah dinilai berdasarkan Indeks Storie
This index expresses numerically the relative degree of
suitability, or value, of a soil for general intensive
agriculture. The rating is based on soil characteristics only
and is obtained by evaluating such factors as depth, texture
of the surface soil, intensity of subsoil, drainage, salts and
alkali, and relief.
Other factors, such as availability of water for irrigation, climate, and
distance from markets that might determine the desirability of
growing certain plants in a given locality are not considered. Therefore
in itself the index cannot be considered as an index of land value.
The index rating is given in the "Guide to Mapping Units" section of
the Eastern Fresno Soil Survey document.
Sumber:
SISR: STORIE INDEX Soil Ratings
Empat faktor yang biasanya digunakan dalam penilaian Indeks Storie.
Keempat Faktor ini adalah (A) karakteristik profil tanah ― terutama
permeabilitas dan kedalaman tanah; (B) tekstur tanah permukaan; (C)
slope; dan (X) faktor atau pembatas lainnya, seperti ketersediaan
hara, banjir, drainage, salts dan alkali, erosion, dan micro-relief.
Each of these four general factors is evaluated on the basis of a “100
percent” rating.
A rating of 100 percent expresses the most favorable, or ideal
condition; and lower percentage ratings are given for conditions less
favorable for crop production.
Sumber:
SISR: STORIE INDEX Soil Ratings
Penilaian Indeks Storie untuk suatu tanah diperoleh dengan
mengalikan keempat faktor tersebut, A, B, C, dan X; sehingga setiap
faktor ikut menentukan nilai akhir.
For example, a soil may have an excellent profile justifying a rating of
100 percent for factor A; excellent texture of the surface soil justifying
100 percent for factor B; a smooth nearly level surface justifying 100
percent for factor C, but a high accumulation of salts of alkali that
would give a rating of 10 percent for factor X.
Multiplying these four ratings gives an index rating of 10 for this soil.
The high accumulation of salts or alkali would dominate in
determining the quality of the soil, render it unproductive for crops,
and justify the low index rating of 10 consistent with a “most-limiting
factor”
Sumber:
SISR: STORIE INDEX Soil Ratings
Indeks Storie (i) untuk menilai suatu tanah merupakan ekspresi
numerik yg menyatakan derajat sampai dimana kondisi tanah aktual
sesuai untuk pertumbuhan tanaman pada kondisi lingkungan (iklim)
yang baik.
Dalam menghitung Indeks Storie ini ada tiga faktor yang
dipertimbangkan, yaitu: Faktor A, profil tanah; Faktor B, tekstur
lapisan tanah permukaan; dan Faktor C, pemodifikasi kondisi tanah,
seperti drainage, alkali, kemasaman, dll.
Each of these three factors is evaluated on a percentage basis, the
most favorable or ideal conditions being rated as 100 percent.
The values of factors A, B, and C are then multiplied, the result being
the index number.
Sumber:
SISR: STORIE INDEX Soil Ratings
The index method is a decided departure from the usual
score card methods of judging and evaluating soils, in which
the various soil characteristics are given values on the basis
of 100 op 1000, and after rating each characteristic on this
basis, the merits are added to ascertain the final rating of
the soil.
With many factors to be considered, no single factor can be
given very heavy weight, and complete failure in one or
more features may still leave the soil rating comparatively
high.
Sumber:
SISR: STORIE INDEX Soil Ratings
The multiplication of factors, A, B, and C permits any one of these to
completely dominate the index rating.
For illustration, a soil may be a deep recent alluvial deposit of fine
sandy loam, probably as ideal in profile and texture as one could find,
and rating 100 percent for factors A and B. But if it was heavily charged
with alkali, its C rating might be 10 or lower.
Multiplying factors A, B, and C would give a final index value of 10,
while under the score card method, where 'alkali‘ would hardly be
given a value of more than 20 points, the rating would be 80 or more!
Heavy accumulations of alkali would absolutely dominate the soil,
rendering it valueless for any economic crop, and the index rating cf 10
or less would be justified.
Sumber:
SISR: STORIE INDEX Soil Ratings
For use in California, the soil profiles, factor A, have been divided into six groups, five
being made up of secondary soils and one of primary soils. In some eastern states,
for instance, Pennsylvania, this distribution might be reversed.
The primary soils could there well be divided into four or five major groups, while
the secondary soils could be combined into one or two, with subgroups where
necessary.
The soil series within each group are given ratings whose value depends upon the
character of the series profile, particularly the characteristics of the subsoils or B
horizons. Profiles with deep subsoils pervious to water and roots, yet sufficiently
retentive to carry crops through moderate drought periods and which are free from
any stratification or other conditions that would retard plant growth are rated as 100
percent.
Profiles with dense claypan subsoils or with hardpan horizons are rated at 5 to 60
percent, depending on the density of the claypan, or the depth to the hardpan.
Primary soils are rated at from 20 to 70, depending on the character of the subsoil
and the depth to bedrock.
Sumber:
SISR: STORIE INDEX Soil Ratings
The B factor evaluates the character of the surface soils, which are
divided into four textural groups—light, medium, medium-heavy, and
heavy textured, with two additional groups to cover the textural
grades that include gravel and stone.
The B factor rates not only the soil texture, but also those other
characteristics that are more or less dependent on texture, such as
consistence, porosity, permeability and tilth. These factors determine
the response of the soil to tillage operations, the rate of water
absorption, the characteristics of the seedbeds and other features that
are vital in agricultural work.
Fine sandy loams, loams, and silt loams are considered ideal and are
rated as 100, while heavy clays rate from 50 to 70. Stony sands may
rate as low as 10 percent. The applications of this index method in
other states and under other climatic conditions might require some
rearrangement of the values assigned to factor B.
Sumber:
SISR: STORIE INDEX Soil Ratings
Factor C was found to be most difficult. It is intended to cover those modifying
conditions that are fundamentally related to the soil, or are inherent in the soil itself.
Among these are conditions of excessive alkalinity or acidity of the soil, marked
infertility, conditions of poor drainage, shallow, steep, or eroded phases untypical of
the soil type, and the like.
Most of these conditions are usually reflected in the soil profile and are considered
in the values assigned under factor A. But the degree of intensity of those
conditions, or their irregular occurrence may not be expressed in the A or B factors,
hence the introduction of this C factor to cover such conditions whenever they exist
in sufficient degree as to modify the soil-plant relationships.
Factors A and B essentially evaluate the Soil Type, factor A covering the series
characteristics and particularly those of the subsoils or B horizons, while factor B
covers the surface soils or the A horizons.
In most locations the third modifying factor C does not appear in the evaluation.
Sumber:
SISR: STORIE INDEX Soil Ratings
Metode Indeks Storie bertumpu pada informasi yang dikumpulkan
dalam survei tanah, dan sangat mudah dilakukan kalau survei tanah
telah diselesaikan. Kalau tidak ada survei tanah maka harus dilakukan
pengambilan contoh tanah lapisan atas (topsoil) dan tanah lapisan
bawah (subsoil).
Obviously, it is not possible to properly evaluate, assess or appraise
the soil without knowing the facts regarding the soil characteristics,
either through the use of the soil maps, or by actual soil exploration.
Guesses as to soil conditions, based on a look at growing crops or
native cover, are usually very unreliable and often misleading.
For Federal Land Bank loans, which may run 20 to 35 years, the soil
factor must be properly evaluated in making the land appraisals.
Sumber:
SISR: STORIE INDEX Soil Ratings
The Storie Index method is being used in California by the assessors in
several counties and by appraisers for the Federal Land Bank and other
financial institutions.
In the Imperial Valley, where the climate, water supply, transportation,
markets, and conditions other than those inherent in the soil are all
quite uniform, the index rating becomes essentially a land evaluation.
In Riverside County, where the availability and quality of irrigation
water determines whether or not the land can be used at all and
where such influences as micro-climate (with variations of only a few
degrees in minimum winter temperatures) may determine whether or
not citrus fruits can be produced on a given site, the soil factor
becomes only one of many factors that must be considered in arriving
at the land evaluation.
Sumber:
STORIE INDEX
The soils in the area, primarily used for cropland, in the
Sacramento Valley, and rangeland, in the Coast Range
foothills, are rated in Table 10a according to the Storie index
(Storie, 1933; 1976).
The soils in the higher Coast Range, primarily used for
timberland, are in Table 10b according to the Storie index
(Storie, 1948).
These indexes express numerically the relative degree of
suitability of a soil for general intensive agricultural uses or
timber uses at the time of the evaluation.
Sumber: http://lawr.ucdavis.edu/classes/ssc118/Colusa_County/storie.html
STORIE INDEX
Index for cropland and rangeland
The rating is based on soil characteristics and is obtained by evaluating soil surface
and subsurface chemical and physical properties, as well as landscape surface
features. The original "Soil-Rating Chart" (Storie 1976).
Some of the terminology used in this chart is not used today. However, when the
ratings were developed, they were compared to today’s terminology to create the
most logical estimate for the rating.
Not considered in the rating are availability of water for irrigation, local climate, size
and accessibility of mapped areas, distance to markets and other factors that might
determine the desirability of growing certain plants in a given locality. Therefore, the
index should not be used as the only indicator of land value.
Where the local economic and geographic factors are known to the user, however,
the Storie index may provide additional objective information for land tract value
comparisons.
Sumber: http://lawr.ucdavis.edu/classes/ssc118/Colusa_County/storie.html
STORIE INDEX
INDEKS UNTUK LAHAN PERTANIAN & GEMBALAAN
Empat faktor yg digunakan untuk menentukan nilai Indeks:
1.
2.
3.
4.
Permeabilitas tanah, available water capacity, and depth of the soil
Tekstur tanah lapisan permukaan
Slope dominan dari tubuh tanah
Kondisi lainnya Other conditions more readily subject to
management or modification by the land user.
In this area these conditions include drainage and flooding, salinity
and alkalinity, fertility, acidity, erosion, and microrelief.
For some soils, more than one of these X conditions are used in
determining the rating.
Sumber: http://lawr.ucdavis.edu/classes/ssc118/Colusa_County/storie.html
STORIE INDEX
INDEKS UNTUK LAHAN PERTANIAN
A rating of 100 percent expresses the most favorable, or ideal, condition for
general crop production. Lower percentage ratings are assigned for less
favorable conditions or characteristics. Factor ratings, in percentages, are
selected from tables prepared from data and yields. Certain properties are
assigned a range of values to allow for variations in the properties to plant
growth and crop yields. Certain properties are assigned a range of values to
allow for variations in the properties that affect the suitability of the soil for
general agricultural purposes.
The index rating for a soil component of a map unit is obtained by
multiplying the percentage rating values given to its four factors, A, B, C, and
X.
If more than one condition is recognized for the X factor for a soil, the value
for each condition acts as a multiplier. Therefore any of the general factors or
X factors conditions may dominate or control the final rating.
Sumber: http://lawr.ucdavis.edu/classes/ssc118/Colusa_County/storie.html
STORIE INDEX
Indeks Untuk Lahan Tanaman dan Lahan Gembalaan
If a map unit consists primarily of one named soil series (a
consociation), the index rating for the named soil component equals
the index rating for the map unit. If a map unit consists of more than
one named component (a complex), ratings are assigned to each
named component (soil series or miscellaneous area, such as "Rock
outcrop"). Inclusions of other soils or minor components not named in
the map unit name, are not used in the calculations.
Map units are assigned grades according to their suitability for general
intensive agriculture as shown by their Storie index ratings. The six
grades and their range in index ratings are:
Grade 1—80 to 100 Grade 2—60 to 79 Grade 3—40 to 59 Grade 4—20
to 39 Grade 5—10 to 19 Grade 6—less than 10
Sumber: http://lawr.ucdavis.edu/classes/ssc118/Colusa_County/storie.html
STORIE INDEX
INDEKS UNTUK LAHAN PERTANIAN
1. Grade 1 are well suited to intensively cultivated crops that are climatically adapted to
2.
3.
4.
5.
6.
the region.
Grade 2 soils are good agricultural soils, although they are not so desirable as soils in
grade 1 because of a less permeable subsoil, deep cemented layers (e.g., duripans), a
gravelly or moderately fine textured surface layer, moderate or strong slopes, restricted
drainage, low available water capacity, lower soil fertility, or a slight or moderate hazard of
flooding.
Grade 3 soils are only fairly well suited to agriculture because of moderate soil depth;
moderate to steep slopes, restricted permeability in the subsoil; a clayey, sandy, or gravelly
surface layer; somewhat restricted drainage; acidity; low fertility; or a hazard of flooding.
Grade 4 soils are poorly suited to agriculture. They are more limited in their agricultural
potential than the soils in grade 3 because of restrictions, such as a shallower depth;
steeper slopes; poorer drainage; a less permeable subsoil; a gravelly, sandy, or clayey
surface layer; channeled or hummocky microrelief; acidity.
Grade 5 soils are very poorly suited to agriculture and are seldom cultivated. They are
more commonly used as pasture, rangeland, or woodland.
Grade 6 soils and miscellaneous areas are not suited to agriculture because of very severe
or extreme limitations. They are better suited to limited use as rangeland, protective
habitat, woodland,
orhttp://lawr.ucdavis.edu/classes/ssc118/Colusa_County/storie.html
watershed.
Sumber:
STORIE INDEX
INDEKS UNTUK LAHAN HUTAN
The rating is based on soil characteristics and is obtained by evaluating soil surface
and subsurface chemical and physical properties, as well as climatic features. The
original "Timber Soil Rating Chart" (Storie 1948).
Some of the terminology used in this chart is not used today. However, when the
ratings were developed, they were compared to today’s terminology to create the
most logical estimate for the rating.
Not considered in the rating are size and accessibility of mapped areas, distance to
markets and other factors that might determine the desirability of timber production
in a given locality. Therefore, the index should not be used as the only indicator of
timber production. Where the local economic and geographic factors are known to
the user, however, the Storie index may provide additional objective information for
timber production.
Lima faktor yg digunakan untuk menentukan nilai indeks :
1. Kedalaman Tanah dan Tekstur tanah
2. Permeabilitas Tanah
3. Karakteristik Kimia Tanah.
4. Drainage dan runoff.
5. Iklim.
Sumber: http://lawr.ucdavis.edu/classes/ssc118/Colusa_County/storie.html
STORIE INDEX
INDEKS UNTUK LAHAN HUTAN
The index rating for a soil component of a map unit is obtained by multiplying the
percentage rating values given to its four factors, A, B, C, D, and E.
If a map unit consists primarily of one named soil series (a consociation), the index
rating for the named soil component equals the index rating for the map unit. If a
map unit consists of more than one named component (a complex), ratings are
assigned to each named component, except rock out crop. Miscellaneous areas are
considered to be unsuited for timber production, and are not rated or considered
zero. Inclusions of other soils or minor components not named in the map unit
name, are not used in the calculations.
Timber site ratings in percent were assigned adjective ratings according to their
suitability for general intensive timber production as shown by figure 1 "Relationship
Between Timber Site Rating and Height - Age Index" in the appendices showing the
"Timber Soil Rating".
The five ratings and their range in index ratings are:
Redwood—100 to 120 High—85 to 99 Medium—50 to 84 Low—30 to 49 NonTimber—0 to 29
Sumber: http://lawr.ucdavis.edu/classes/ssc118/Colusa_County/storie.html
STORIE INDEX
KELAS
KAPABILITAS TANAH
UNIT KAPABILITAS TANAH
Unit Kapabilitas
Sifat Tanah atau Faktor Pembatas
1
Ada bahaya aktual atau potensiao erosi tanah oleh air atau angin.
2
Bahaya Drainage atau genangan (swp or poorly drained, flooded or
ponded)
3
Subsoil mempunyai permeabilitas lambat atau sangat lambat.
4
5
Tekstur kasar atau berkerikil.
Tekstur halus atau snagat halus.
6
Salinity or alkali, sufficient to constitute a continuing limitation or hazard.
7
Stones, cobbles, or rocks sufficient to interfere with tillage.
8
Hardpan or hard unweathered bedrock within the root zone.
9
Low inherent fertility, associated with strong acidity, low calcium-
10
High organic matter content - peats and mucks.
11
Coarse sandy or very gravelly substrata limiting to root penetration and
moisture retention
TIMBER SOIL RATINGS
Studi lapangan dimulai tahun 1947 untuk menganalisis hubungan
antara tanah, iklim dan kualitas lokasi hutan tanaman (timber).
Empat faktor tanah disimpulkan mempengaruhi atau membatasi pertumbuhan jenis
conifers di California. Keempat faktor ini adalah A – Kedalaman tanah dan tekstur
tanah; B – Permeabilitas tanah; C – Karakteristik kimia tanah; D - Drainage dan
runoff. Selain itu juga ada faktor iklim.
High sites for growing conifers in California need a deep soil of sufficiently fine
textured to hold about 12% of more of moisture; a permeable profile; have no toxic
chemical characteristics; be of acid reaction; well drained; and have a total annual
rainfall of more than 40 inches.
Hasil penilaian pendahuluan berdasarkan penetapan nilai persentase untuk lima
faktor : A – Kedalaman tanah dan tekstur; B – permeabilitas tanah; C – sifat kimia
tanah; D - Drainage dan runoff; E - Iklim.
Four climatic zones are considered in rating the timber sites in the Sierra Nevada and
Coast Range Mountains of California and Nevada.
Timber Site Rating = A x B x C x D x E.
Sumber: http://lawr.ucdavis.edu/classes/ssc118/Colusa_County/appendixc_b.html
TIMBER SOIL RATINGS
Timber Soil Rating Chart
Indeks untuk menilai kesesuaian tanah untuk Hutan Tanaman Kayu di California
Faktor A: Depth-Texture (tidak ada efek penilaian untuk tekstur dengan kapasitas air
tersedia 12% atau lebih.)
Kedalaman-Tekstur
Kedalaman lebih 72”
60-72
48-60
36-48
24-36
12-24
0-12
Sumber:
Nilai (%)
Kelas
Kedalaman
100
90-100
80-90
70-80
50-70
30-50
0-30
5
5
5
4
3
2
1
TIMBER SOIL RATINGS
Faktor B: Permeabilitas Tanah
Permeabilitas
Moderately rapid &
rapidly permeable
profiles
Moderately slow &
slowly permeable
profiles
Very slowly
permeable profile
Nilai (%)
Kelompok Profil
Tanah
100
I; II; VII-I, II; VIII-I, II;
IX-I, II
80-90
III; III+; VII-III, III+;
VIII-III, III+; IX-III, III
30-70
IV; V; VII-IV; VIII-IV;
IX-IV
Sumber:
TIMBER SOIL RATINGS
Faktor C: Kimia Tanah (Alkalinity, Salinity, dll.)
Kelas
Toksisitas
Efek Kimiawi
Nilai (%)
Tidak ada
100
Ringan
80-90
S
Moderat
20-80
M
Parah / Berat /
Kuat
0-20
A
Sumber:
TIMBER SOIL RATINGS
Faktor D: Drainage-Runoff
Nilai (%)
Drainage
symbol
100
w
Excessively
80-95
r
Somewhat poorly
40-80
i
Buruk dan Sangat Buruk (Sgt
Jelek)
10-40
p
Drainage
Well & moderately well
Sumber:
TIMBER SOIL RATINGS
Faktor E: Iklim
CF--Coastal Fog (Redwood)
CR--Coastal Range
(Douglas fir)
WS--Westside Sierra
(Pine)
ES--Eastside Sierra
Pine (P.J.)
Rainfall (in.)
Rating
percent
Rainfall
(in.)
Rating
percent
Rainfall
(in.)
Rating
percent
Rainfall
(in.)
Rating
percent
45
120
45
100
45
100
40
90
40
110
40
95
40
95
35
80
35
100
35
90
35
90
30
70
30
90
30
60-70
30
50-60
25
60
25
80
25
30
25
20
20
50
20
30
15
40
Sumber:
TIMBER SOIL RATINGS
Pentingnya Klasifikasi Tanah dan Penilaian Tanah bagi Lokasi
Hutan Timber
Klasifikasi tanah bersama dengan nilai tanah untuk kualitas lokasi
hutan tanaman (timber) akan memperkuat survei sumberdaya hutan
di California melalui dua cara:
First it will facilitate and improve the quality of the timber site
classification. Previously this classification has been base entirely on
the height-age relationship of dominant trees without reference to the
soil. Ratings were satisfactorily made where dominants were present,
as in the case of virgin timber or older second growth.
On the other hand difficulties were encountered in making reliable
ratings in many cut-over or burned-over areas where suitable
dominants were infrequent or entirely absent.
Sumber:
TIMBER SOIL RATINGS
Pentingnya Klasifikasi Tanah dan Penilaian Tanah bagi Lokasi
Hutan Timber
Di beberapa lokasi, dimana tidak ada pertumbuhan tegakan kayu
timber, maka tidak dapat ditentukan apakah lokasi itu sesuai untuk
hutan tanaman kayu timber.
Kesulitan ini dicoba diatasi dengan jalan menilai lokasi tersebut
berdasarkan kualitas tanahnya.
Second, the maps produced by the survey, since they show the
location of good, fair, poor, and unsuitable sites for growing various
kinds of timber trees, will have greater usefulness to those interested
in managing forest lands for timber crops.
Sumber:
TIMBER SOIL RATINGS
Hubungan antara Rating Tapak Hutan dengan Indeks tinggi-umur
Sumber : http://lawr.ucdavis.edu/classes/ssc118/Colusa_County/appendixc_b.html
STORIE INDEX OF SOILS
Sumber: STELA – April 2013