1. According to ISSS classification, silt ranges between ___________________

 0.05–2.0 mm

 0.0002–0.05 mm

 0.002–0.02 mm

 0.02–2.0 mm

2. High concentration of sodium (Na⁺) in soil reduces aggregate stability primarily by _____________________

 Promoting flocculation through divalent cation bridging

 Enhancing cementation between particles

 Inducing clay dispersion via diffuse double layer expansion

 Increasing organic binding agents

3. A soil with a bulk density of 1.75 g cm-3 in the root zone is likely to _______________

 Be extremely sandy with many large pores

 Be compacted and restrict root penetration

 Have very low particle density

 Have excellent root growth and high porosity

4. Particle density remains relatively constant because it is controlled by ____________________

 Mineralogical composition of soil solids

 Tillage

 Management practices

 Soil moisture

5. A soil described as “friable” if it is ___________________

 Very hard and cemented

 Structureless and loose with no aggregation

 Easily crumbled into aggregates under slight pressure

 Extremely sticky and plastic when wet

6. Which of the following best defines soil texture?

 The arrangement of soil aggregates

 The density of soil solids

 The relative proportion of sand, silt, and clay particles

 The color of the soil

7. Which pore class stores the majority of plant-available water?

 Macropores

 Mesopores

 Micropores

 Gravel pores

8. Soil aggregates are stabilized by all of the following mechanisms EXCEPT _______________

 Excessive tillage

 Organic matter

 Fungal hyphae

 Polyvalent cations (Ca²⁺, Al³⁺)

9. Soil aeration is primarily controlled by ________________

 Particle density

 Soil porosity, moisture content, and biological activity

 Munsell value

 Soil Color

10. Which soil water fraction is held at very high tension and is unavailable to plants?

 Hygroscopic water

 Available water

 Capillary water

 Gravitational water

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