Soil survey is essentially a study of soil morphology in the field. Soil survey includes classification of soils of the area in well-defined units, characterisation of soil properties, plotting their extent and boundaries on a map and predication of the adaptability of these soils to various uses.
soil survey – (i) The systematic examination, description, classification, and mapping of soils in an area. Soil surveys are classified according to the kind and intensity of field examination.
(ii) The program of the National Cooperative Soil Survey that includes developing and implementing standards for describing, classifying, mapping, writing, and publishing information about soils of a specific area.
The main objectives of soil survey:
(1) To describe and classify soils giving uniform system of classification with uniform nomenclature in order to correlate the soils of different area.
(2) To show distribution of different soils in the field (soil mapping).
(3) To provide data for making interpretations as to the adaptability of particular soils for agricultural purpose and also for many other purposes (as in soil management).
Soil surveys are of the following three types:
(3) Detailed reconnaissance
1. Detailed Soil Survey:
In this, soil boundaries are plotted accurately on maps on the basis of observations made throughout the surveyed area. In this, geographical distribution of soil is also described. Detailed soil surveys are important in the sense that they provide information’s needed for planning land use and management and formulating agricultural research and extension programmes.
2. Reconnaissance Survey:
In this, soil boundaries are plotted from the observations made at intervals.
3. Detailed Reconnaissance Survey:
In this, a part of surveyed area is plotted on the map by detailed method and remainder by reconnaissance method. In mapping of soils either aerial photographs are taken or good topographic maps are made. In mapping of cultivated areas, generally a scale of four inches to a mile is used but detailed or special maps are made on scales of six inches, eight inches or twelve inches to a mile.
Methods of Soil Survey:
They primarily concern the studying of soil profiles in the filed as well as in the laboratory; mapping soils according to well-defined legends ; collecting all relevant information about the climate, physiography, hydrology, geology, vegetation, present land use; scientific data about recommended practices and their responses; socio-economical conditions of the area; and preparing soil reports and soil maps.
Topography is the study of shape and features on the surface of the Earth. These features typically include natural formations such as mountains, rivers, lakes, and valleys, forests, glaciers etc. Manmade features such as roads, dams, and cities may also be included.
Topography is a combination of two Greek words ‘topos’ meaning ‘place’ and ‘graphein’ meaning ‘to write.’ It is extremely important to chart and predict weathers, lay roads and plan other transportation means, to plan architectural constructions, study geology, farming, water body management etc.
Mapping is a crucial part of earth science and are wonderful tools that help us find our way in a street, in a city, in a country, in fact, anywhere on the Earth. There are some maps that show different physical features of the Earth. These maps are called topographic maps. Topographic maps use a particular type of line, known as a contour line, to depict different elevations on a map.
How is information collected to make topographic maps
There are mainly two primary methods of surveying the landforms – direct survey and indirect survey.
Direct survey –
A direct survey is when a topographer on ground, uses surveying equipment, to measure the location and elevation of the land. Have you ever seen a surveyor along the road sometime taking measurements with the help of a leveling instrument placed on a tripod? They are doing just that!
Indirect survey –
Remote or inaccessible areas on the Earth may be mapped using indirect methods. These methods include satellite images, images taken from aeroplanes, helicopters, radar, and sonar (underwater).
Topographical maps include five categories of elements as following:
- Toponymy which includes names of places, water bodies and highways
- Vegetation including wooded and non-wooded areas
- Reliefs including mountains, hills, valleys and plateaus
- Waters, including oceans, lakes, rivers and stream
- Culture establishments such as cities, railroads and power lines
How are different topographical features highlighted on the map
Different colors are used in topographic maps,
- Black shows buildings, railroads, power lines and geographical elements
- Red shows transportation routes
- Orange shows unconstructed roads
- Brown is used for elevation
- Green shows forested areas
- Blue is used to depict different water bodies
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