The USDA Land Capability Classification System

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The USDA Land Capability Classification System

The best known of these systems is the United States Department of Agriculture system (Klingebiel and Montgomery, 1961).
The USDA land classification system is interpretative, using the USDA soil survey map as a basis and classifying the individual soil map units in groups that have similar management requirements.
At the highest of categorization, eight soil classes are distinguished, namely:

Class I soils

have few limitations restricting their use. Erosion hazards on these soils are low; they are deep, productive and easily worked.
For optimum production, these soils need ordinary management practices to maintain productivity, as regards both soil fertility and favorable physical soil properties.

Class II soils

have some limitations that reduce the choice of plants or require moderate conservation practices.
Limitations of soils in Class II include (singly or in combination) the effect of gentle slopes, moderate susceptibility to erosion, less than ideal soil depth, somewhat unfavorable soil structure, slight to moderate correctable salinity, occasional damaging overflow, wetness correctable by drainage, slight climatic limitation.
Soils in this class require more than ordinary management practices for obtaining optimum production and for maintaining productivity.

Class III soils

have severe limitations that reduce the choice of plants or require special conservation practices.
The limitation of soils in this class are those of Class II, but in higher degree; including additional limitations such as shallow depth, low moisture-holding capacity, and low fertility that is not easily corrected.
Class III soils require considerable management inputs, but even so, choice of crops or cropping systems remains restricted because of inherent limiting factors.

Class IV soils

have very severe limitations that restrict the choice of plants and or require very careful management.
Restrictions, both in terms of choice of plants and or management and conservation practices are greater than in Class III to such an extent that production is often marginal in relation to the inputs required.

Class V soils

have few or no erosion hazards but have other limitations, impracticable to remove, that restrict their use to pasture, range, woodland, or wildlife food and cover.
Although they may be level or nearly level, many of these soils are subject to inundation or are stony or rocky.

Class VI soils

have severe limitations- that make them generally unsuited to cultivation and limit their use largely to pasture or range, woodland, or wildlife food cover.
This class is a continuation of Class IV, with very severe limitations that cannot be corrected.
They may serve for some kinds of crops, such as tree crops, provided unusually intensive management is practiced.

Class VII soils

have very severe limitations that make them unsuited to cultivation and also, restrict their use largely to grazing, woodland, or wildlife.
The limitations are such that these soils are not suited for any of the common crops.

Class VIII soils