Physical Properties of Soil MCQ's

Physical Properties of Soil

• Soil texture is a measure of the proportion of different sized particles (sand, silt, clay) in a soil sample.
• Soil structure is the arrangement of soil particles in a soil.
• Colloidal clay particles have the greatest capacity for ion exchange.

Soil Texture and Drainage

• Sand, silt, and clay particles have different properties that affect drainage, aeration, and fertility.
• The ratio of Sand, Silt, and Clay determines the soil texture.
• Soil texture is a fixed property of soil that cannot be changed.

Soil Types

• Sandy Soils: large air pores, free draining, easy to work with, dries out quickly, and poor soil with little nutrients.
• Clay Soils: holds water easily, little leaching, fertile soil, and poor drainage.
• Loam Soil: a soil that contains equal amounts of sand, silt, and clay, with intermediate characteristics of clay and sandy soils.

Organic Matter

• Humus is the product of the breakdown of organic matter (humification).
• Humus is a dark, sticky material that absorbs water and can greatly improve soil quality.
• Humus is rich in nutrients and improves soil structure.

Determining Soil Texture

• Hand testing, sedimentation, and soil sieve can be used to determine soil texture.

Soil Structure

• The floccules contain pores within the floccule called micropores, and pores between adjacent floccules are larger and called macropores.
• Good structure is necessary for healthy plant growth, nutrient availability, and microbial activity.

Impact of Various Factors on Soil Structure

• Soil compaction destroys soil structure, reduces pore space, drainage, and aeration, and affects plant growth and soil organisms.
• Organic matter loss leads to poorer structure, less nutrient availability, lower water retention, and lower CEC (cation exchange capacity).
• Erosion, sedimentation, and weathering result in loss of OM filled topsoil, loss of sediments, and risk to water quality.

Soil Water

• Water is held in soil as it is attracted to the negative charges of the clay particle.
• Hygroscopic water forms a thin layer around the soil particle.
• Capillary water is held in pores within the soil aggregates and is available for plant uptake.
• Gravitational water is moved through the soil by gravity and is only available on a temporary basis to plants.

Soil Colour

• Dark brown or black colour indicates rich in humus, highly fertile soils, and nutrient rich.
• Light colour or grey soils tend to have low fertility, low in nutrients, and suffer from leaching.

Soil Temperature

• Lower temperature results in lower germination and lower water and mineral uptake.

Physical Properties of Soil

• Soil texture is a measure of the proportion of different sized particles (sand, silt, clay) in a soil sample.
• Soil structure is the arrangement of soil particles in a soil.
• Colloidal clay particles have the greatest capacity for ion exchange.

Soil Texture and Drainage

• Sand, silt, and clay particles have different properties that affect drainage, aeration, and fertility.
• The ratio of Sand, Silt, and Clay determines the soil texture.
• Soil texture is a fixed property of soil that cannot be changed.

Soil Types

• Sandy Soils: large air pores, free draining, easy to work with, dries out quickly, and poor soil with little nutrients.
• Clay Soils: holds water easily, little leaching, fertile soil, and poor drainage.
• Loam Soil: a soil that contains equal amounts of sand, silt, and clay, with intermediate characteristics of clay and sandy soils.

Organic Matter

• Humus is the product of the breakdown of organic matter (humification).
• Humus is a dark, sticky material that absorbs water and can greatly improve soil quality.
• Humus is rich in nutrients and improves soil structure.

Determining Soil Texture

• Hand testing, sedimentation, and soil sieve can be used to determine soil texture.

Soil Structure

• The floccules contain pores within the floccule called micropores, and pores between adjacent floccules are larger and called macropores.
• Good structure is necessary for healthy plant growth, nutrient availability, and microbial activity.

Impact of Various Factors on Soil Structure

• Soil compaction destroys soil structure, reduces pore space, drainage, and aeration, and affects plant growth and soil organisms.
• Organic matter loss leads to poorer structure, less nutrient availability, lower water retention, and lower CEC (cation exchange capacity).
• Erosion, sedimentation, and weathering result in loss of OM filled topsoil, loss of sediments, and risk to water quality.

Soil Water

• Water is held in soil as it is attracted to the negative charges of the clay particle.
• Hygroscopic water forms a thin layer around the soil particle.
• Capillary water is held in pores within the soil aggregates and is available for plant uptake.
• Gravitational water is moved through the soil by gravity and is only available on a temporary basis to plants.

Soil Colour

• Dark brown or black colour indicates rich in humus, highly fertile soils, and nutrient rich.
• Light colour or grey soils tend to have low fertility, low in nutrients, and suffer from leaching.

Soil Temperature

• Lower temperature results in lower germination and lower water and mineral uptake.

This quiz covers the physical properties of soil, including texture, structure, and capillary water. It defines key terms and concepts related to soil composition and behavior.