The land use capability classification was developed by the United State Department of Soil Conservation Service, as a method to assess the extent of limitations such as erosion risk, soil depth, wetness and climate that create restrictions in the agricultural activities for crop production.
The objective of classification is to categorize the land into a unit with similar kind and degree of limitations. The basic unit is the capability unit which consists of a group of soil types of sufficiently similar features in respect of soil depth, profile, slope and degree of erosion to make them suitable for similar crops and use of similar conservation measures. This classification system categorises the whole land into eight classes from Class I to Class VIII, in which class I to IV are suitable for cultivation, and V to VIII are unsuitable for cultivation.
All these classes are described below:
1. Class I:
The lands falling in this class are very good in all respects. They are nearly level and have no risk of erosion; soil depth is appreciable and easy to work. They hold water very well and rich in fertility. Use of fertilizers and lime in cover crops, and use of crop rotation is required to maintain soil fertility and soil structure.
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The other features of this class lands are given as under:
i. This land use capability class is the class of green colour.
ii. Soils of this class have very few or no limitations that restrict their use.
iii. The land is nearly level; and erosion hazard is low.
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iv. The soils are deep, well drained, easily workable and water holding capacity is also good
v. Soils are suitable for a wide range of crops/plants; can be used for cultivated crops, pastures, forests, and wildlife food and cover.
vi. Lands are either fairly well supplied with plant nutrients or highly responsive to the fertilizers.
vii. Soils are not subject to damage caused by overland flow.
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viii. These soils need ordinary management practices to maintain their productivity level up to mark. The practices may be the use of fertilizers, lime, cover and green-manure crops, conservation of crop residues and crop rotations.
2. Class II:
The land is good and suitable from every point of view, but in comparison to Class I some certain physical conditions make it not so good. Soil slope is gentle; depth is moderate; subject to occasional overland flow; may require drainage facility; there can be moderate risk of damage when cultivated, but can be controlled by adopting tillage practices.
The other important features of this class lands are outlined as under:
i. It is denoted as the class II of Yellow colour.
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ii. Soils of this class have few limitations, which restrict the choice of crops.
iii. Limitations of soils may be due to effect of one or more of the factors such as gentle slope; slight susceptibility to erosion; lesser than ideal soil depth; occasional damaging overflow; wetness which can be removed by drainage, but existing permanently as a moderate limitation; slight to moderate salinity and slight climatic limitation on land use and management.
iv. Soils require careful management.
v. Very few limitations are there; and practices are easy to apply.
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vi. The lands may require one or more soil conservation practices like terracing, strip cropping, contour cultivation, water disposal, crop rotation, cover and green-manuring crops, stubble mulching, use of fertilizers, manure and lime.
vii. The soils can be used for growing cultivated crops, raising pastures, forests and for wildlife food and cover.
3. Class III:
Land is moderately good for cultivation. Soil contains moderate fertility on moderate slopes; subject to more risk of damage but can be used for growing crops, provided that the plant cover must be maintained. Class III lands are moderately sloping, and there should be intensive use of erosion-control measures to control the erosion, if crops are to be taken in regular rotation. The land is poorly drained, so requires drainage facility.
Various features of this LUCC are mentioned as under:
i. It is presented by Yellow colour.
ii. Soils of this class have moderate limitations, which cause restrictions on choice of crops for cultivation; or require special conservation measures.
iii. There is greater restrictions on soil as compared to the class II; and when such soils are used for cultivation, then it is very difficult to apply and maintain the conservation measures.
iv. Limitations of soils may be due to effects of one or more of the features, like moderately sloping land; moderately susceptibility to water or wind erosion; frequent overflow accompanied with few crop damage; very slow permeability of the sub-soil; wetness or continuing water-logging shallow soil depth up to the bed-rock, hard-pan or clay-pan which limits the rooting-zone and water storage; low moisture-holding capacity; moderate salinity and moderate climatic limitations.
4. Class IV:
Land is good enough for occasional cropping under proper management. The soil is rich in fertility. Slope is steep; subject to severe erosion; very severe damage but can be controlled by taking precautionary measures. Generally, such lands are kept under pasture, but grain crops can also be taken once in five or six year’s rotation.
The other features of this LUCC are mentioned below:
i. Soils involve severe limitations, which restrict the choice of crops and require careful management.
ii. The degree of restrictions regarding use of these soils is greater than the class III lands; and also there is more limited choice on the crops.
iii. Use of these soils for cultivating the crops requires a very careful management; and conservation practices are more difficult to apply and maintain.
iv. There is very limited use of the soils for cultivation of crops, because of the effect of one or more of the permanent features such as steep slopes; severe susceptibility to water or wind erosion; severe damage due to past erosion; shallow soil; low moisture-holding capacity; frequent overflow accompanied with severe crop damage; excessive wetness or continuing hazard of water-logging after drainage; severe salinity and moderately adverse climate.
v. These soils can be used for crops, pastures, forests and wildlife food and cover.
5. Class V:
Land is nearly level and is not subject to erosion because of wetness, stoney or some permanent obstructions. Such lands are not suitable for cultivation.
Generally, kept under pasture and/or forestry but grazing should be regulated to prevent the cover from destroying various features of this class land are outlined as under:
i. This LUC class is indicated by dark green or un-coloured.
ii. Soils have little or no erosion hazard, but involve limitations, which removal is very difficult.
iii. Soils are used mainly for pastures, forests, wildlife food and cover.
iv. Lands are nearly level and are not subject to more than the slight wind or water erosion.
v. Cultivation is not possible because of one or more limitations, i.e. overflow, stoniness, wetness or severe climate.
vi. Examples of class-V lands are –
a. Soils of lowland subject to frequent overflow, which prevents the normal yield of cultivated crops.
b. Nearly level soils having normal yield of cultivated crops.
c. The level or nearly level stony or rocky soils.
d. Ponded area, where drainage for cultivated crops is not feasible, but the soils are suitable for grasses or trees.
vii. Soils of class-V are suitable for perennial vegetations (grazing and forestry with few or no limitation).
viii. Pastures can be improved, and benefits from proper management can be expected.
ix. Physical conditions of soils are such that they can be seeding, liming, fertilizing, and water flow control with contour furrows, construction of drainage ditches and diversions of water for improvement of pastures.
6. Class VI:
Lands are not suitable for cultivation; shallow soils on steep slopes; used for grazing and forestry; grazing should be regulated to preserve the plant cover; if the plant cover is destroyed, then the land use should be restricted until the cover is re-established.
The other features are as follows:
i. Colour of this class soils is orange.
ii. Soils have severe limitations that make them unsuitable for cultivation, and confine their use largely for pastures, or forests, or wildlife food and cover.
iii. Soils have continuing limitations, which cannot be removed.
The limitations may be:
a. Steep slope
b. Very severe erosion hazard
c. Very severe effect of past erosion
d. Stoniness
e. Shallow root-zone
f. Excessive wetness or overflow
g. Low moisture holding capacity
h. Salinity or sodium
i. Severe climate.
iv. Soils of this class are subject to moderate limitations on grazing or forestry use.
7. Class VII:
Lands are not only unsuitable for cultivation to common crops, but also have severe limitations to use for grazing or forestry. Generally, these lands are droughty and swampy; severe risk of damage even when they are kept under pasture. Strict grazing or forest management is essential to follow.
Different features of this class lands are given as under:
i. Colour of this LUC class is brown.
ii. Soils have very severe limitations that make them unsuitable for cultivation and restrict their use largely for grazing or forestation, or wildlife food and cover.
iii. The soils are subject to severe limitations or hazards for grazing and forestry use.
iv. Physical conditions of soils are such that they cannot be allowed for pasture improvement and water-control practices.
v. Soil restrictions are severe than those in class VI.
8. Class VIII:
Lands are very rough, not suitable for wood land or grazing. Generally, these lands are suitable for wild life conservation, development of recreation spots or watershed conservation.
The other important characteristics are given below:
i. Colour of this LUC class is purple.
ii. Soils and landforms have limitations that require to preclude first, and then use for commercial plant production. These lands are restricted to use for recreation, wild-life food and cover or to water-supply, watershed protection or for aesthetic purposes.
iii. A significant return from the soils and landforms cannot be expected by taking the grasses or trees. Limitations cannot be removed.
Limitations may be due to effects of one or more of the following factors:
a. Erosion or erosion hazard
b. Severe climate
c. Wet soil
d. Stones
e. Low moisture holding capacity
f. Salinity, bad lands, rock outcrops, sandy beaches, marshes, deserts, river wash, mine tailings and nearly barren lands.
Limitations of Different LUCC:
The permanent soil limitations and intensity of safe use of different classes of LUCC are illustrated in Fig. 22.3.
This figure describes the following features about limitations, for which a particular class land is not recommended to use:
1. Class I land has no any limitation; can be safely used for all practices starting from very intensive cultivation to wild life. Since, this land has sufficient capability to produce good crop yield, therefore predominantly recommended for very intensive cultivation; and not for other practices like grazing, forestry or wild life purposes.
2. Class II land comprises few limitations, by virtue of which this class land is not recommended for very intensive cultivation purposes.
3. Class III land has greater limitations than the class II land regarding fertility, slope, subject to erosion, risk of damage etc., as result not allowed for intensive or very intensive crop cultivation, but can be used for growing crops, provided that the plant cover is maintained.
4. Class IV lands involve severe limitations as compared to the class III land, therefore they are not recommended for intensive crop cultivation, but cultivated occasionally; normally hay or pasture crops are grown.