18 Questions
Which soil class is characterized by severe erosion and shallow effective depth?
Class VI
Which soil class is suitable for wildlife or recreation purposes?
Class VIII
Which soil class has severe limitations for pasture or forestry use and requires extensive erosion control?
Class VII
Which soil class is characterized by very wet conditions and is unfit for cultivation?
Class V
Which soil class has hazards such as steep slopes, erosion, and shallow soils?
Class VI
Which soil class is characterized by moderately thick to thick topsoil and slow permeability?
Class V
Which soil class is unsuitable for cultivation and has severe limitations for pasture or forestry use?
Class VI
Which soil class requires extensive management of conservation practices to control erosion and is characterized by severe erosion and/or slope?
Class VII
Which soil class is only suited for wildlife or recreation purposes and is usually extremely stony, sandy, or wet?
Class VIII
Which land capability class is suitable for crop production with certain conservation practices?
Class III
What does the term 'permeability' in soil classification refer to?
The movement of water or air through the soil
What is the main factor influencing the soil's tillability after rainfall in soil classification?
Drainage
How is slope calculated?
By dividing the amount of vertical change in elevation by the horizontal distance the change takes place over and multiplying by 100
What does permeability of subsoil refer to?
The ability of air and water to move through the subsoil
What does effective depth refer to in land evaluation?
The depth to which plant roots can easily penetrate
How is slope calculated?
By dividing the vertical change in elevation by the horizontal distance and multiplying by 100
What does the permeability of subsoil refer to?
The ability of air and water to move through the subsoil
What is the surface texture of soil determined by?
The proportion of sand, silt, and clay in the topsoil
Study Notes
Soil Classification and Land Capability
- Slope categories are based on the percentage of elevation change over a given distance, with Texas having six categories ranging from nearly level to very steep.
- Erosion is classified as none to slight, moderate, severe, or very severe based on the percentage of original topsoil remaining.
- Topsoil texture is determined by the proportion of sand, silt, and clay, with fine, medium, and coarse textures having specific characteristics.
- Permeability rates the movement of water or air through the soil as rapid, moderate, or slow, based on the subsoil type.
- Drainage is categorized as excessive, well-drained, moderate, somewhat poor, poorly drained, or wet, influencing the soil's tillability after rainfall.
- Effective depth refers to the depth to which plant roots can easily penetrate and is classified as deep, moderately deep, shallow, or very shallow.
- Land capability classes are a system designed to classify land based on its best use and are divided into two groups for crop production or permanent vegetation.
- There are eight land capability classes, with higher numbers indicating less suitability for crop production.
- Class I land is very good for crop production, with ideal soils and no restrictions, while Class II has some limitations but is suitable for crop production.
- Class III may be used for crop production with certain conservation practices, and Class IV is borderline cultivatable land with severe limitations.
- Class V-VIII are suited only for permanent vegetation as pasture or forest and have increasing limitations for crop production.
- Each land capability class has specific characteristics related to slope, topsoil thickness, erosion, texture, permeability, drainage, and effective depth.
Test your knowledge of land evaluation and basic soil science with this quiz on the six land factors that determine the best use for an area of land. Understand the criteria for evaluating slope and erosion to determine the suitability of land for various purposes.
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