all the basics related to soil survey starting from the reason why do we need soil survey and what is history of surveys, their kinds objectives and all related details.

1. Soil Survey And Land
Evaluation
UMAR MUNIR

2. Soil Survey
 Soil survey is the process of classifying soil types and other soil
properties in a given area and geo-encoding such information.
 It applies the principles of soil science, and draws heavily from
geomorphology, theories of soil formation, physical geography, and
analysis of vegetation and land use patterns
 Primary data for the soil survey are acquired by field sampling and by
remote sensing.
 Remote sensing principally uses aerial photography but LiDAR and
other digital techniques are also important for soil surveys.

3. History
 The selection of good land for farming is as old as agricultural
land use.
 During early Holocene, some 8000 years ago the first farmers
in Europe were cultivating the relatively rich loess soils and
alluvial plains shows that these people were aware of major
differences in fertility between major land units, and that they
were able to judge which soil was more productive than others.

4. History
 Gong (1994) stated that the oldest historical record of soil survey and
land classification is most likely the Chinese book “Yugong” in which
soils of China were classified into three categories and nine classes,
based on soil color, texture and hydrological features.
 According to Simson (1990), soil survey started with the systematic
assessment of agricultural land in the United States in the late 1890s.
 Europe soon followed suit in the early 1900s. A peak in soil survey
activity was reached during the 1950s, 1960s and 1970s, particularly
with surveys for development projects in Africa, Asia and Latin America.

5. History of soil surveys in
Pakistan
 The soil survey of Pakistan (SSP) came into being in 1962 as a
project titled “Soil Survey Project Of Pakistan” under the ministry
of Food and Agriculture, Govt. of Pakistan. The project was
assisted by United Nation Special Fund (UNDP) with Food and
Agriculture Organization (FAO) of the United Nation as its
executing agency.
 The project was regularized as a department in July, 1973.

6. History of soil surveys in
Pakistan
 Main objective of project was “to prepare an inventory of
Pakistan’s soil resources through standard reconnaissance soil
surveys in the form of reports and maps, which would assist the
government in planning of projects aiming at new land
development, soil conservation etc. and overall economic
development of the country.”

7. History of soil surveys in Pakistan
 Through the “Soil Survey Project Of Pakistan” , in total 27
reconnaissance Soil Survey reports and analog maps were
prepared and covered 38 % of the area.
 After regularization (1973) of Department, Soil Survey Of
Pakistan, completed 43 reports and covered 96 % of
country’s area.

8. Importance
 In order to make practical use of soil science principles, farmers,
ecologists, and global modelers must all know not only the “what” and
“why” of soils, but must also know the “where.” if engineers planning an
airport runway are to avoid the hazards of swelling clay soils, they must
know where these soils are located.
 Soil survey data is an invaluable tool for comparing soil properties over
broad areas. It can dramatically facilitate planning and preparation for
onsite investigation. Soil maps can effectively communicate the nature of
soil differences across an area. In the context of general land-use planning,
soil survey data provides an irreplaceable tool for basic and objective
based resource planning.

9. Importance
 Soil surveys provide an accurate and scientific knowledge about
different soils, their kinds and nature, and extent of distribution
so that one can make prediction about their characters and
potentialities.
 It also provides adequate information in terms of land form,
terraces, vegetation as well as characteristics of soils ( texture,
depth, structure, stoniness, drainage, acidity, salinity and so on)
which can be utilized for the planning and development.

10. Objectives
1. Investigate the geographical distribution of different soils
that occur in a given area.
2. Determine the most important characteristics of the soils
i.e. texture, depth, structure, stoniness, drainage, acidity,
salinity.
3. To provide data for making interpretations as to the
adaptability of particular soils for agricultural purpose.
4. Delineate map units and describe them in a logical legend
in terms of dominant, associated and inclusion soil units,
including classification of soils. Soil surveys ultimately
lead to evaluation of the quality of the different map units
for specific types of land use.

11. Limitations
 Soil survey data seldom contain detailed, site-specific
information. They are useful for broad regulatory planning
and application.
 Soil survey information cannot replace site-specific
details, which require onsite investigation. It is a valuable
tool where acquiring onsite data is not feasible or is cost
prohibitive.

12. Soil Survey Methodology
Soil surveying usually comprises of six essential steps:
1. Background study.
2. Ground truthing of collected geo-referenced information
such as aerial or remote sensing data.
3. In-depth soil profile study and soil sampling
4. Extrapolation and boundary verification
5. Laboratory analysis
6. Data crunching, map production, interpretation and
reporting.

13. Parts of Soil Survey
Soil survey comprise of three main parts:
 Text: It explains all the details of the geography of
the area under consideration.
 Maps: They provide brief description about the
soil types found in area under consideration with
their characteristics. Detailed aerial photographs
with specific soil types are outlined and indexed.

14. Parts of Soil Survey
 Tables : Tables containing specific physical, chemical, and
engineering properties such as water holding capacity,
corrosion properties, soil depth, texture etc. along with
general information about the various soils such as total
area, comparisons of production of typical crops and
common range plants. They also include extensive
interpretations for land use planning

15. Characters of Soil Survey
1. Pedons and Polypedons
2. Map scales
3. Mapping units
4. Base maps
5. Observable features and inferred qualities
6. Delineating boundaries
7. Mapping legend
8. Field traverse selection

16. 1. Pedon
 The smallest unit or volume of soil that contains all the
soil horizons of a particular soil type.
 It usually has a surface area of
approximately 1 sq m (10.76 sq ft)
and extends from the ground surf-
ace down to bedrock.

17. Polypedon
 Two or more contiguous pedons, which are all within the
defined limits of a single soil series.
 Pedons may be considered as
building blocks that make up
both soil taxonomic classes
and soil mapping units.

18. Map scales
 The scale of a map is the ratio of length on the map to
actual length on the ground. A scale of 1:20,000 is
commonly used for detailed soil maps and indicates that 1
cm on the map represents a distance of 20,000 cm (0.2km)
on the ground.

19. 2. Mapping units
 Mapping Units are a collection of areas which have similar
defined soil properties due to these similar soil properties,
interpretations can be made for use and management of the
soils in the Mapping Unit.
 Map units: Have a two letter code (Capital, then lower case),
usually followed by a Slope Class code (a Capital letter from A
to F).
 Examples:
Mardin channery silt loam, 2 to 8 percent slope = MaB
Arkport fine sandy loam, 2 to 6 percent slope = ArB

20. Slope Classes
Designated by a A, B, C, D, E or F at the end of the Map
Unit Symbol
Code Class Description
A Little or none Little or no slope: 0 - 3 % gradient
B Gentle Gentle slopes: 2- 8 % gradient.
C Moderate Moderate slopes: 8- 15 % gradient.
D Steep Steep slopes: 15-25% gradient.
E Extremely steep Extremely steep slopes: 25-35% gradient.
F Excessively steep Excessively steep slopes: 35-60%gradient.

21. Mapping unit types
 Soil Phase: A phase is a subdivision based on some
important deviation that influence the use of the soil, such
as surface texture, degree of erosion, slope, stoniness, or
soluble salt content. For example, Cecil sandy loam, 3 to
5% slope and a Hagerstown silt loam, stony phase.

22. Mapping units types
 Consociation: In a consociation, delineated areas use a
single name from the dominant component in the map
unit. Dissimilar components are minor in extent. The
smallest practical mapping unit for most detailed soil
surveys is an area that contains primarily one soil series
and usually only one phase of that soil series.

23. Mapping units types
 Soil Complexes: When contrasting soils occur adjacent to
each other in a pattern so intricate that the delineation of
each kind of soil on a soil map becomes difficult, if not
impossible.
 A soil complex contains two or three distinctly different
soil series.

24. Mapping units types
 Soil Associations: General groupings of soils that typically
occur together in a landscape and could be mapped
separately.
 Undifferentiated Groups: These units consist of soils that
are not consistently found together, but are grouped and
mapped together because their suitabilities and
management are very similar for common land uses.

25. Base maps
 A map having only essential outlines and used for the
plotting or presentation of specialized data of various
kinds.
 Following are the types of different base maps used in
different types of soil surveys:
1. Cadastral/village maps
It has a scale of 1:5000 to 8000.
It shows locations of individual holding,
ponds, roads and streams. Physiographic
features and contour lines are not available.

26. Base maps
2. Topographical maps
It has a scale 1:25,000 to 1:2,50,000.
It shows roads, tracks, streams, water
sources along with contour lines and
physiographic features.
3. Aerial photographs
It has a scale of 1:10,000 to 1:50,000.
Photographs of land surface are taken
from aircraft vertically. Then they are
viewed stereoscopically- three dimensional

27. Base maps
view. Landform, vegetation, land use, roads and tracks
can be directly seen. Soil properties, geology and other
land properties require indirect interpretation.
4. IRS data ( Earth resource satellite imagery)
It has a scale of 1:25,000 to 1:2,50,000.
It gives synoptic view of large areas
(185x185 km) on one image.

28. 3. Observable features
 In the completed soil survey, the features of each kind of
soil are listed. Among these observed directly are slope(
degree, shape, and pattern), stoniness, depth, and the color,
structure, texture, and other significant features of each
horizon of the soil profile.

29. Inferred qualities
 The qualities which are not determined directly rather they
are partly determined through use of scientific instruments
e.g. content of clay, pH, plant nutrients, organic matter and
through interpretation from observed features e.g. soil
fertility is estimated from observable characteristics,
results of experimental plots, from experience of farmers
having records on fields consisting largely of one kind of
soil.

30. 4. Delineation of boundaries
 Delineation means describing the boundaries in soil maps.
Soil delineation boundaries are drawn wherever there is a
significant change in the type
of soil.
 Boundaries can be predicted
with change in landscape and
five soil-forming factors
determine which soils are
found at particular place.

31. Delineation of boundaries
 Augers and hydraulic probes are used to confirm that type
of soil predicted to occur in the area is the type actually
there.

32.  A simple but laborious and time consuming approach to
obtaining soils information is to make auger borings at
regular intervals (say, every 50 m) in a grid pattern across
the landscape. Point with similar properties can then be
connected to form soil boundaries.

33. 5. Soil Mapping Legend
 Soil mapping legend is backbone of any map as it defines
all the characteristics of a map.
 A legends describes maps in
a way which is simple, easy
to understand, and readily
adaptable to local needs.

34. Kinds Of Legends
 1. The identification legend: each mapping unit---type,
phase, variant, complex, association, or miscellaneous land
type---has a symbol that is placed in areas on the map to
identify it.
 The identification legend is a list of all these symbols and
their names, arranged alphabetically and numerically so
that one may see the symbol for each kind of soil and the
kind of soil for each symbol.

35. Identification legend
 The mapping unit includes the name of soil series, soil
depth class, textural class, slope class, erosion class and
other phases such as stoniness, rockiness, gravelliness, etc.
The name of series is designated by Capital letter or a
Capital letter associated with small letter of English
alphabet. Arabic numeral and textural class designates
depth class by small English alphabets followed by erosion
class designated by Arabic numeral.

36. Identification legend
 G, S and R show gravelliness, stoniness and rockiness
respectively. The intensity of the above is shown drawing bars
above the letter for slight and below the letter for severe. E.g.
K3rC2G connotes,
K = Kamliakheri series
3 = Moderate depth class (25 – 50 cm)
r = Clay textural class
C = Gentle slope (3 – 5%)
2 = Moderate erosion class
B = Severely Gravelly phase

37. 2. The Descriptive Legend
 A guide to each soil mapper for all symbols and for
descriptions of all mapping units in ways that show their
relationships to each other, how they are differentiated
from one another, their relationships to physiography,
geology, and vegetation, and a tentative assessment of their
use capabilities and management requirements.

38. 6. Field traverse selection
 Definition: A traverse is a series of straight lines called
traverse legs. The surveyor uses them to connect a series
of selected points called traverse stations (TS). The
surveyor makes distance and angle measurements and uses
them to compute the relative positions of the traverse
stations on some system of coordinates.
 Starting Control: The surveyor needs certain elements of
starting data, such as the coordinates of a starting point and
an azimuth to an azimuth mark. The different variations in
starting control are grouped into several general
categories..

39. 1. Known Control Available:
Survey control is available in the form of existing
stations with the station data published in a trigonometric
list, or higher headquarters may establish the station and
provide the station data. The surveyor obtains the azimuth to
an azimuth mark (starting direction) by referring to a
trigonometric list or computing from known coordinates.
2. Maps Available:
When a map of the area is available, the
approximate coordinate of the starting station is scaled
from the map.

40. (For survey purposes, starting data scaled from a map are
considered to be assumed data.) The surveyor determines the
starting direction by scaling it from the map.
3. No Maps Available:
When neither survey control nor maps are available, the
coordinate of the starting point is assumed. The surveyor
determines the starting direction by the most accurate means
available.

41. Types Of Traverse
1. Open Traverse
An open traverse originates at a starting station,
proceeds to its destination, and ends at a station whose
relative position is not previously known. The open traverse
is the least desirable type of traverse because it provides no
check on fieldwork or starting data. For this reason, the
planning of a traverse always provides for closure of the
traverse. Traverses are closed in all cases where time permits.

42. 2. Closed Traverse:
A closed traverse starts at a point and ends at the same
point or at a point whose relative position is known. The
surveyor adjusts the measurements by computations to minimize
the effect of accidental errors made in the measurements. Large
errors are corrected.

43. Types Of Soil Surveys
Following are most widely adopted types of soil
surveys:
1. Detailed Soil Survey
2. Reconnaissance Soil Survey
3. Detailed Reconnaissance Soil Survey
4. Generalized Soil Survey
5. Schematic Soil Survey
6. Exploratory Soil Survey

44. Reconnaissance Soil Survey
 Soils are not studied in detail i.e. observations are taken at
a longer interval and noted down on the Survey topo
sheets of scale 1: 2,50,000 to 1: 50,000.
 The mapping units used are soil association, complexes
and soil series.
 Identifies the kinds of soils and their extent of distribution
and recognizes area suitable for intensive farming.
 1000 acres are surveyed per day in this category.

45. Reconnaissance Soil Survey
 Base maps used are Topo sheets, aerial photographs or
satellite imageries.
 It is low intensity soil survey.
 Soil profile is examined at 3-6 kms or even shorter.
 On a reconnaissance soil map the boundaries between the
mapping units are plotted from observations made at
intervals and not necessarily throughout their whole
course as on the detailed soil survey maps.

46.  The RSS of Pakistan was based
on intensive aerial photo
interpretation followed by field
examination of soils made along
planned traverses across the
landscape.

47. Detailed Soil Survey
 This is a high intensity soil survey. In this survey, mapping
units are soil series, soil types and soil phases.
 The larger scale cadastral maps or aerial photographs
ranging from 1:4,000 to 1:10,000 are used as base maps.
 These cadastral maps possess several prominent permanent
features such as lakes, ponds, rivers, rivulets, roads,
habitation, hillocks and field boundaries with Khasra No.
which help surveyor in delineating soil boundaries.

48.  Depending upon the soil heterogeneity and variation in
terrain form, the profile site for characterization of soils
would be located.
 There should be at least one soil profile for every 80 to 100
ha of area. Auger bore examination and sampling is done at
intervals of 200 to 500 m.
 The minimum map able unit will depend on scale of map.
However, the minimum area that warrants the
differentiation of soil series should be in the range of 4 to 5
ha

49.  It provides the following information's, which are essential
for any land development program.
1)Proper diagnosis of soils
2)Scientific land use planning
3)Soil amendments for judicious use of chemical
fertilizer
4) Soil , land, water, crop and nutrient management
5) Generation of soil health cards for dissemination of
soil information to farming community
 The use of aerial photographs has advantages over cadastral
maps for its wealth of details and three-dimensional view.

50. 6)Development of Soil Information System
7) Optimal utilization of soil resources

51. Detailed Reconnaissance
Soil Survey
 In this type both surveys i.e. detailed and reconnaissance
are carried out.
 First reconnaissance soil survey is carried out and
subsequently about 15 per cent of the area where research
projects are to be established, are surveyed in detail.
 On detailed reconnaissance map some portions satisfy the
specifications of detailed soil map while some satisfy
reconnaissance.

52. Detailed Reconnaissance
Soil Survey
 Boundaries between these two types of maps may be made
in one of two ways:
(1) The boundaries may follow section lines or other
land lines and be shown in a smaller sketch map on
the margin of the soil map.
(2) The legend on the map may be divided into two
parts. The mapping units listed under the
reconnaissance legend and boundaries are defined
and mapped according to specifications of for

53. Detailed Reconnaissance
Soil Survey
reconnaissance and same goes for the
mapping units under detailed map.
 If the problem soils of an area are to
be studied, RSS is to be taken for the
whole area and DSS in those
problematic areas identified.

54. Generalized Soil Maps
 In order to see the broad geographic relations among soils,
small-scale maps are necessary to bring out the contrasts
among regions.
 Generalized maps from detail soil survey are best. Such
maps vary in scale and detail from soil association maps of
counties at a scale of 1 inch equals 1 mile (1:63,360) to
single maps of large regions showing associations
dominated by one or more great soil groups.

55. Schematic Soil Maps
 In form and appearance these resemble generalized maps
of soil associations.
 Scales are usually small say 1:1,000,000 or smaller.
 In new and undeveloped regions, it is useful to have an
approximate or estimated soil map even in advance of an
organized field soil survey. Such maps may be made by
estimating the soil pattern.

56. Exploratory Soil Maps
 Exploratory surveys are not proper survey.
 Usually rapid road traverse are taken to get the information
about the area.
 Scale of exploratory soil surveys varies from 1:2,000,000-
1,500,000.
 It is useful for macro level planning for varied agro-based
development programs.

57. Orders Of Soil Surveys
 1st Order Soil Survey:
Type of Survey = Intensive
Survey scale = 1:1000-1:15,000
Size of mapping unit = smaller than 0.5 ha
Components of map units = phases of soil series
Kind of map units = Mostly consociations; some
complexes
Remote sensing sources = high n low altitude aerial
photography, SPOT image digital data
Use in land planning = Management surveys

58. Orders Of Soil Surveys
 2nd Order Soil Survey
Type of Survey = Detailed
Survey scale = 1:12,000-1:32,000
Size of mapping unit = 0.5 - 4 ha
Components of map units = Soil series , series phases
Kind of map units = consociation, complexes;
few association
Remote sensing sources = Landsat thematic Mapper
digitized data, SPOT image digital data, High n Low altitude
aerial photography
Use in land planning = Feasibility surveys, Management
surveys

59. Orders Of Soil Surveys
 3rd Order Soil Survey
Type of Survey = semi-detailed
Survey scale = 1:20,000-1:65,000
Size of mapping unit = 1.5 – 15 ha
Components of map units = Families, series, series phases
Kind of map units = Associations or complexes; some
consociations
Remote sensing sources = Landsat thematic mapper digitized
data, SPOT image digital data, high n low altitude aerial
photography
Use in land planning = Project location, Feasibility surveys

60. Orders Of Soil Surveys
 4th Order Soil Survey
Type of Survey = Reconnaissance
Survey scale = 1:50,000-1:300,000
Size of mapping unit = 15-250 ha
Components of map units = Great groups, sub groups,
families
Kind of map units = Associations, consociations, some
complexes
Remote sensing sources = Landsat thematic mapper digitized
data, SPOT image digital data, high altitude aerial
photography
Use in land planning = Resource inventory, Project location

61. Orders Of Soil Surveys
 5th Order Soil Survey
Type of Survey = Reconnaissance
Survey scale = 1:250,000-1:10,000,000
Size of mapping unit = 2.5-500 sq km
Components of map units = order, suborder, great group
Kind of map units = association, some consociation,
undifferentiated group
Remote sensing sources = Landsat thematic mapper
digitized data, SPOT image digital data
Use in land planning = Resource inventory

62. Soil Spatial Variability
 Definition: Spatial variability occurs when a quantity that
is measured at different spatial locations exhibits values
that differ across the locations. Spatial variability can be
assessed using spatial descriptive statistics such as the
range.
 Types:
1. Small Scale Soil Variability
2. Medium Scale Soil Variability
3. Large Scale Soil Variability

63. Small Scale Soil Variability
 Soil properties changes markedly with distance. Within a
few hectares of farmland. Within a sub urban house and
even within a soil individual.
 At this scale the variations might be due to small changes
in topography, thickness of parent material or the effect of
living organisms.
 The small scale variability is difficult to measure however,
in some cases the plant height and vigor of vegetation
reflects the subsurface soil variability. Chemical properties

64. Small Scale Soil Variability
 like plant available phosphorus may be dramatically
variable because of previous application of fertilizer in
band placement or small spots. Biological soil properties
like microbial respiration or bacterial diversity are very
sensitive to the presence of “hotspots” such as actively
growing plant roots or animal waste. Physical soil
properties such as water infiltration capacity can be
especially variable due to such influences as earthworm
burrows or cracks caused by clay shrinkage.

65. Medium Scale Soil Variability
 For many soil properties, variability across landscape is
related primarily to differences in a particular soil-forming
factor, such as soil topography or parent material.
Identifying one member of the set often makes it possible
to predict soil properties in the landscape positions
occupied by other members of the set. Such as,
 Lithosequences :it means adjacent soil shows different
soil profile properties due to difference in parent material
(rock or mineral deposited).

66. Medium Scale Soil Variability
 Chronosequences : it means similar parent materials of both soils
but both have different age.
 Toposequences : it means soils arranged according to changes in
relief.
 Catena : a set of soils that differs on the basis of drainage or due to
difference in relief but same parent material.
A catena of soil usually consists of a well drained member near the
slope the sloope summit, sometimes an excessively drained member on
shoulder slope, a moderately well-drained member near the toe slope,
and somewhat to very poorly drained member at bottom.

67. Medium Scale Soil Variability
 A soil catena is a sequence of different soil profiles that
occur down a slope. The various soils found in catena can
often be distinguished by the color of soil surface
particularly color of B horizon. In tropical soils, dark gray
color at bottom and rusty red at the top is seen

68. Large Scale Soil Variability
 At a very large scale the variability may be due to change
in climate and vegetation pattern and secondary due to
parent material differences. Although it is often useful to
refer to general regional soil characteristics, it must be
remembered that much localized variation exists within
each regional grouping. E.g. Oxisols are found in hot and
humid regions. Aridisols located in desert regions.

69. Techniques And Tools For
Mapping Soils
 The first step in mapping soils is to cllect and study older
or smaller-scale soil maps, geological and topographic
maps etc.
 Once the soil survey begins, the soil scientist’s task is
threefold: (1) to define each soil unit to be mapped (2) to
compile information about the nature of each soil (30 to
delineate boundaries where each soil unit occurs in the
landscape.

70. Techniques And Tools For
Mapping Soils
 Soil scientists may use computers and satellites, but they also
use spades and augers. Despite all technologies of recent years,
the heart of soil mapping is still the soil pit. A soil pit, whether
dug by hand or with a backbone, is basically a rectangular hole
large enough to study a pedon.
 A soil description is then written in a standard format that
facilitates communication with other scientists and comparison
with other soils. Then samples from each horizon are taken for
laboratory analysis which will provide information for
chemical, physical and mineralogical of each soil.