Soil Science – Basic Definitions In agronomy and physical geography, the term “soil texture” specifically refers to:

Introduction / Context:
Soil texture is one of the most fundamental descriptors used by agronomists, soil scientists, and civil engineers to predict water retention, nutrient availability, aeration, and tillage behavior. A precise understanding of what texture measures helps in selecting crops, scheduling irrigation, and interpreting laboratory tests such as particle-size analysis.

Given Data / Assumptions:

• The question asks what the term “soil texture” refers to.
• We are dealing with standard soil science terminology used in agricultural handbooks and soil surveys.
• Texture categories include sand, silt, and clay proportions, commonly summarized by a texture triangle.

Concept / Approach:
Soil texture is strictly about the size distribution of mineral particles (percent sand, silt, clay). It does not capture shape, chemistry, or arrangement; those are captured by other terms (structure, mineralogy, porosity). Texture drives key hydraulic properties: coarse textures (sandy) drain fast, while fine textures (clayey) hold more water but have lower hydraulic conductivity when compacted.

Step-by-Step Solution:

Verification / Alternative check:
Texture is routinely reported as, for example, 60% sand, 30% silt, 10% clay, corresponding to a “sandy loam.” This aligns with standard laboratory methods and extension guides.

Why Other Options Are Wrong:

• The distribution of mineral particles in the soil: Too vague; it could imply spatial arrangement (structure) rather than size classes.
• The crystal distribution in soil: Refers to mineral crystallography, not textural grading.
• None of the above: Incorrect because option A exactly defines texture.

Common Pitfalls:
Confusing soil texture (particle-size fractions) with soil structure (aggregation, peds) or with organic matter content. Texture is about size, not arrangement or composition.

Final Answer:
the size distribution of the mineral particles composing the soil