#1
Which of the following is not a primary soil particle size?
Gravel
ExplanationGravel is composed of larger particles than those typically classified as primary soil particles.
#2
What is the primary constituent of soil organic matter?
Humus
ExplanationHumus is the stable, decomposed organic matter in soil.
#3
What is the term used to describe the movement of water downward through soil?
Percolation
ExplanationPercolation is the process of water moving vertically through soil.
#4
Which of the following nutrients is considered a macronutrient for plant growth?
Calcium
ExplanationCalcium is a macronutrient essential for plant cell structure and function.
#5
Which of the following soil horizons contains the most organic matter and is commonly referred to as the 'topsoil'?
A Horizon
ExplanationThe A Horizon, or topsoil, contains the highest concentration of organic matter.
#6
What is the term for the loss of soil fertility and productivity due to erosion, salinization, or other factors?
Soil degradation
ExplanationSoil degradation refers to the decline in soil quality and productivity.
#7
Which of the following soil horizons is the top layer where organic matter accumulates?
O Horizon
ExplanationThe O Horizon, or organic horizon, is where organic matter accumulates at the soil surface.
#8
What is the soil texture if it has approximately equal proportions of sand, silt, and clay?
Loamy
ExplanationLoamy soil has a balanced mixture of sand, silt, and clay particles.
#9
What soil order is characterized by the presence of permafrost?
Gelisols
ExplanationGelisols are soils with permafrost within 100 cm of the soil surface.
#10
Which of the following is a common soil conservation practice that involves alternating strips of crops with strips of vegetation?
Strip cropping
ExplanationStrip cropping alternates rows of crops with rows of perennial vegetation to reduce erosion.
#11
Which of the following is a common method for improving soil structure and aeration?
Mulching
ExplanationMulching helps improve soil structure, moisture retention, and aeration.
#12
What soil type is characterized by high fertility, dark color, and a high organic content?
Mollisols
ExplanationMollisols are fertile soils with high organic matter and dark coloration.
#13
Which of the following is a primary determinant of soil fertility?
pH
ExplanationSoil pH, the measure of acidity or alkalinity, strongly influences nutrient availability.
#14
What is the process of soil particles binding together into larger clusters or aggregates called?
Flocculation
ExplanationFlocculation is the aggregation of soil particles into larger clumps.
#15
Which of the following is a measure of the soil's ability to hold onto and supply essential nutrients to plants?
Soil fertility
ExplanationSoil fertility refers to the soil's capacity to provide essential nutrients to plants.
#16
What is the term for the process of soil particles being displaced downward in the soil profile?
Illuviation
ExplanationIlluviation is the deposition of soil material in lower soil horizons.
#17
What is the term for the process of soil particles being moved horizontally in the soil profile?
Erosion
ExplanationErosion involves the lateral movement of soil particles within the soil profile.