CRSS 3060 Test 2
Essential elements for plants - Answers -C, H, O
Macronutrients - Answers -N, P, K
Micronutrient cations - Answers -Fe, Mn, Cu, Zn, Co
Micronutrient Anions - Answers -B, Cl, Mo
secondary elements - Answers -Ca, Mg, S
Nitrogen - Answers -the most limiting factor for non-leguminous plants. Soil microbes
also take up nitrogen, and soil nitrogen is usually caught in humus (main soil reservoir)
denitirification - Answers -Conversion of nitrates into nitrogen gas (anaerobic conditions)
Immobilization - Answers -uptake of inorganic nutrients by organisms or plants
Mineralization - Answers -release of organically bound nutrients into soluble, mineral
forms through decomposition
Nitrification - Answers -ammonia is converted to nitrate ions (NO3-).
Phosphorus - Answers -2nd most abundant mineral for plants; plants use mycorrhizae
to take up scare P in soils
Potassium - Answers -a lot of K available in soils from feldspar and mica; readily
absorbed on CEC sites. added as a fertilizer to ag soils
Ca and Mg - Answers -aka the lime elements; found in primary minerals and released
during the weathering process.
Sulfur - Answers -humus has high S content; can be a problem via acid rain
Biggest risks with micronutrient cations: - Answers --direct toxicity
-excessive plant uptake
-leaching or runoff
Micronutrient anions in the SE: - Answers -tightly bound by Fe oxides and can be
deficient.
, ideal pH range for plants - Answers -5.5-6.5
Macroorganisms in soil - Answers -worms, insects, burrowing animals
microorganisms in soils - Answers -bacteria, fungi, algae, protozoa, single-celled
organisms, etc
Bacteria - Answers -most abundant organism in soils. heterotrophic, decomposers,
most are aerobes, some anaerobes. Turns leaf litter and other o-material into CO2 and
humus.
Fungi - Answers -specialize in decomposing lignin, or wood fiber. Second most
abundant.
Actinomycetes - Answers -give soil its characteristic earthy smell, resemble fungi but
are actually filamentous bacteria, break down tough debris such as woody stems, bark,
or newspaper
Algae - Answers -photosynthetic protists that live in croplands or pastures
Protozoa - Answers -carnivorous organisms in the soil
roles of soil organisms - Answers --Soil formation
-Decomposition
-Mineralization and Nutrient Cycling
-Humus Synthesis
factors of humus synthesis: - Answers --wetter soils
-cooler temperatures
-Finer textured soils
-Higher residue breakdowns
aerobic respiration - Answers -is exothermic and efficient.
anerobic respiration - Answers -takes place via fermentation and is less efficient
Critical C:N ratio separating mineralization from immobilization is - Answers -30:1
increasing humus by 1%= - Answers -10 tons of new humus into a soil
Other microbial functions in soils: - Answers --N-Cycle organisms
-Mycorrhizae
-Pathogens
Soil Productivity - Answers -Capability of a soil for producing plants under a specified
system of management
Essential elements for plants - Answers -C, H, O
Macronutrients - Answers -N, P, K
Micronutrient cations - Answers -Fe, Mn, Cu, Zn, Co
Micronutrient Anions - Answers -B, Cl, Mo
secondary elements - Answers -Ca, Mg, S
Nitrogen - Answers -the most limiting factor for non-leguminous plants. Soil microbes
also take up nitrogen, and soil nitrogen is usually caught in humus (main soil reservoir)
denitirification - Answers -Conversion of nitrates into nitrogen gas (anaerobic conditions)
Immobilization - Answers -uptake of inorganic nutrients by organisms or plants
Mineralization - Answers -release of organically bound nutrients into soluble, mineral
forms through decomposition
Nitrification - Answers -ammonia is converted to nitrate ions (NO3-).
Phosphorus - Answers -2nd most abundant mineral for plants; plants use mycorrhizae
to take up scare P in soils
Potassium - Answers -a lot of K available in soils from feldspar and mica; readily
absorbed on CEC sites. added as a fertilizer to ag soils
Ca and Mg - Answers -aka the lime elements; found in primary minerals and released
during the weathering process.
Sulfur - Answers -humus has high S content; can be a problem via acid rain
Biggest risks with micronutrient cations: - Answers --direct toxicity
-excessive plant uptake
-leaching or runoff
Micronutrient anions in the SE: - Answers -tightly bound by Fe oxides and can be
deficient.
, ideal pH range for plants - Answers -5.5-6.5
Macroorganisms in soil - Answers -worms, insects, burrowing animals
microorganisms in soils - Answers -bacteria, fungi, algae, protozoa, single-celled
organisms, etc
Bacteria - Answers -most abundant organism in soils. heterotrophic, decomposers,
most are aerobes, some anaerobes. Turns leaf litter and other o-material into CO2 and
humus.
Fungi - Answers -specialize in decomposing lignin, or wood fiber. Second most
abundant.
Actinomycetes - Answers -give soil its characteristic earthy smell, resemble fungi but
are actually filamentous bacteria, break down tough debris such as woody stems, bark,
or newspaper
Algae - Answers -photosynthetic protists that live in croplands or pastures
Protozoa - Answers -carnivorous organisms in the soil
roles of soil organisms - Answers --Soil formation
-Decomposition
-Mineralization and Nutrient Cycling
-Humus Synthesis
factors of humus synthesis: - Answers --wetter soils
-cooler temperatures
-Finer textured soils
-Higher residue breakdowns
aerobic respiration - Answers -is exothermic and efficient.
anerobic respiration - Answers -takes place via fermentation and is less efficient
Critical C:N ratio separating mineralization from immobilization is - Answers -30:1
increasing humus by 1%= - Answers -10 tons of new humus into a soil
Other microbial functions in soils: - Answers --N-Cycle organisms
-Mycorrhizae
-Pathogens
Soil Productivity - Answers -Capability of a soil for producing plants under a specified
system of management
