AGRY 105 Exam 3 (Lectures 25-37)
questions n correct answers
2025/2026
Plant nutrition - correct answer ✔✔The study of the chemical elements and compounds
necessary for plant growth, plant metabolism, and their external supply
Soil Fertility - correct answer ✔✔The capacity of a soil to provide crops with essential plant
nutrients
Non-mineral nutrients (3) - correct answer ✔✔Carbon, Hydrogen, Oxygen
Macronutrients (elements needed in large amounts) (3) - correct answer ✔✔Nitrogen,
Phosphorus, Potassium
Secondary nutrients (needed in larger amounts, but less than macros) (3) - correct answer
✔✔Calcium, Magnesium, Sulfur
Micronutrients (needed in very small amounts) (8) - correct answer ✔✔Boron, Iron,
Molybdenum, Manganese, Zinc, Copper, Chlorine, Nickle
Essential nutrients for photosynthesis - correct answer ✔✔N, P, K, Mn, Mg, S, Fe, Cl
Factors that add nutrients to the soil (5) - correct answer ✔✔1. Atmosphere
2. Fertilizers
3. Biological fixation
,4. Microbial decomposition of organic matter
5. Weathering of parent materials
Factors that remove nutrients from the soil (5) - correct answer ✔✔1. Leaching
2. Nutrient Fixation
3. Erosion/runoff
4. Volatilization
5. Plant uptake
Common soil anions (negative charge) (5) - correct answer ✔✔OH- (hydroxide), SO4 -2 (sulfate)
Cl- (chloride), NO3 - (nitrate), H2PO4 - (dihydrogen phosphate)
Common soil cations (positive charge) - correct answer ✔✔H+ (hydrogen), K+ (potassium), Na +
(sodium), Mg +2 (magnesium), Ca +2 (calcium), Fe +2 (ferrous), Fe +3 (ferric)
Adsorption - correct answer ✔✔Adhesion of atoms, ions, or molecules from a gas, liquid, or
dissolved solid to a surface
Leaching - correct answer ✔✔The movement of a material/nutrient in a solution by the
drainage of water through the soil
Soil solution - correct answer ✔✔The water content of a soil, which is a solution containing
various gases, organic matter, and minerals
Contributors to the soil solution (6) - correct answer ✔✔1. Weathering of soil rocks and
minerals
2. Decomposition of organic matter
3. Biological fixation
, 4. Atmosphere
5. Fertilizer/other additions
6. Number of exchange sites and organic matter
Mass flow - correct answer ✔✔Dissolved nutrients move to the root in soil water that is flowing
towards the roots as the plant takes up water for transpiration
Diffusion - correct answer ✔✔Nutrients move from higher concentration to lower
concentration at the root
Root interception - correct answer ✔✔Roots obtain nutrients by physically contacting nutrients
in the soil solution of on soil surfaces
Functions of Nitrogen (N) in plants - correct answer ✔✔1. N is a major part of the chlorophyll
molecule (essential for photosynthesis)
2. N combines with C, H, O, and S to create amino acids, the building block of proteins
3. Amino acids are used in forming protoplasm, the site for cell division in thus for plant growth
and development
4. Since all plant enzymes are made of proteins, N is needed for all of the enzymatic reactions in
a plant
Nitrogen compounds - correct answer ✔✔N2 - Atmospheric
NH3 - Ammonia
NH4+ - Ammonium
NO3- - Nitrate
NO2- - Nitrite
N2O - Nitrous Oxide
questions n correct answers
2025/2026
Plant nutrition - correct answer ✔✔The study of the chemical elements and compounds
necessary for plant growth, plant metabolism, and their external supply
Soil Fertility - correct answer ✔✔The capacity of a soil to provide crops with essential plant
nutrients
Non-mineral nutrients (3) - correct answer ✔✔Carbon, Hydrogen, Oxygen
Macronutrients (elements needed in large amounts) (3) - correct answer ✔✔Nitrogen,
Phosphorus, Potassium
Secondary nutrients (needed in larger amounts, but less than macros) (3) - correct answer
✔✔Calcium, Magnesium, Sulfur
Micronutrients (needed in very small amounts) (8) - correct answer ✔✔Boron, Iron,
Molybdenum, Manganese, Zinc, Copper, Chlorine, Nickle
Essential nutrients for photosynthesis - correct answer ✔✔N, P, K, Mn, Mg, S, Fe, Cl
Factors that add nutrients to the soil (5) - correct answer ✔✔1. Atmosphere
2. Fertilizers
3. Biological fixation
,4. Microbial decomposition of organic matter
5. Weathering of parent materials
Factors that remove nutrients from the soil (5) - correct answer ✔✔1. Leaching
2. Nutrient Fixation
3. Erosion/runoff
4. Volatilization
5. Plant uptake
Common soil anions (negative charge) (5) - correct answer ✔✔OH- (hydroxide), SO4 -2 (sulfate)
Cl- (chloride), NO3 - (nitrate), H2PO4 - (dihydrogen phosphate)
Common soil cations (positive charge) - correct answer ✔✔H+ (hydrogen), K+ (potassium), Na +
(sodium), Mg +2 (magnesium), Ca +2 (calcium), Fe +2 (ferrous), Fe +3 (ferric)
Adsorption - correct answer ✔✔Adhesion of atoms, ions, or molecules from a gas, liquid, or
dissolved solid to a surface
Leaching - correct answer ✔✔The movement of a material/nutrient in a solution by the
drainage of water through the soil
Soil solution - correct answer ✔✔The water content of a soil, which is a solution containing
various gases, organic matter, and minerals
Contributors to the soil solution (6) - correct answer ✔✔1. Weathering of soil rocks and
minerals
2. Decomposition of organic matter
3. Biological fixation
, 4. Atmosphere
5. Fertilizer/other additions
6. Number of exchange sites and organic matter
Mass flow - correct answer ✔✔Dissolved nutrients move to the root in soil water that is flowing
towards the roots as the plant takes up water for transpiration
Diffusion - correct answer ✔✔Nutrients move from higher concentration to lower
concentration at the root
Root interception - correct answer ✔✔Roots obtain nutrients by physically contacting nutrients
in the soil solution of on soil surfaces
Functions of Nitrogen (N) in plants - correct answer ✔✔1. N is a major part of the chlorophyll
molecule (essential for photosynthesis)
2. N combines with C, H, O, and S to create amino acids, the building block of proteins
3. Amino acids are used in forming protoplasm, the site for cell division in thus for plant growth
and development
4. Since all plant enzymes are made of proteins, N is needed for all of the enzymatic reactions in
a plant
Nitrogen compounds - correct answer ✔✔N2 - Atmospheric
NH3 - Ammonia
NH4+ - Ammonium
NO3- - Nitrate
NO2- - Nitrite
N2O - Nitrous Oxide
