Chapter 31: Soil and Plant Nutrition

soil

the highly weathered outer layer of the Earth’s crust

rocks, sand, silt dissolved minerals, and microorganisms

what are the components of soil?

sand, silt, and clay

what are the particle class sizes that can make up soil?

half

how much of the soil volume is occupied by pores filled with air or water?

45%

what percentage of soil is inorganic matter?

5%

what percentage of soil is organic matter?

topsoil

top layer of soil that is a mixture of mineral particles, living organisms, and humus

humus

organic decaying material

relative amounts of sand, silt, and clay

how are soils characterized?

degree of water and nutrient binding

what does soil composition determine?

topsoil and subsoil

what are the two main divisions of soil?

O, A, B, and C

what are the four soil horizons?

organic horizon

soil horizon that is nutrient rich with lots of decaying organic debris

A horizon

soil horizon with a mixture of organic and inorganic material; lots of biological activity and roots

B horizon

soil horizon with some roots, but substantial water and dissolved mineral nutrients

C horizon

soil horizon composed of largely weathering parent material (bedrock fragments)

parent material, climate, topography, biology, and time

what does soil formation and profile depend on?

rhizosphere

region of soil right around the roots

negatively

how are soil particles charged?

cation exchange capacity

important property of soil that allows for storage of mineral nutrients

photosynthesis

what is the major source of plant nutrition?

photosynthesis

fixation of atmospheric CO2 into simple sugars, using the energy of the sun

essential, inorganic, ions, obtained via uptake in the soil, passed onto other organisms, and biogeochemical cycles

what are the characteristics of mineral nutrients?

macronutrients

nutrients used in plants in relatively large amounts

N, P, K, Ca, Mg, S, (C, H, O)

what are the macronutrients plants need?

micronutrients

essential minerals used in very small amounts 

Fe, Mn, B, Mo, Cu, Zn, Cl, Ni, Co, Na, and Si

what are the micronutrients plants need?

severe effects on plant growths

what are the results of a deficiency of any macro or micro nutrient within a plant?

multiple deficiencies, influencing another elements, and disease symptoms can mimic nutrient deficiency symptoms

what are deficiency symptoms affected by?

to build proteins

what do plants need ammonium or nitrate for?

nitrogen-fixing bacteria 

with what organisms have plants formed symbiotic relationships with to get more ammonium or nitrate?

protection and carbohydrates

what do plants provide to Rhizobium bacteria?

expand surface area available for water and nutrient uptake

what is the benefit of mycorrhizal fungi to plants?

90%

what percentage of vascular plants have symbiotic associations with mycorrhizal fungi?

parasitic plants

plant that is dependent on its host for survival

Dodder and American cancer root

what are some examples of a parasitic plant?

both

are parasitic plants photosynthetic or nonphotosynthetic?

saprophytic plants

plants that obtain food from decomposing organic matter in soils; no chlorophyll and nonphotosynthetic

epiphytes 

plants that grow on other plants but no not parasitize; obtain nutrients and water from crevices in trees and atmospheric moisture; photosynthetic

carnivorous plants

plants that often grow in acidic soils and bogs that are deficient in nitrogen and other mineral nutrients; trap and digest small animals, primarily insects, to extract nitrogen and additional nutrients; modified leaves trap and lure prey

venus fly traps

carnivorous plants when hairs are touched, the two halves of the leaf snap together

pitcher plant

plants with pitcher-shaped leaves with a cavity filled with digestive fluid and microbial community

sundew

plants with glandular trichomes that secrete both sticky mucilage and digestive enzymes

waterwheel

aquatic plant that uses trigger hairs and snaps shut to capture and digest small aquatic animals

phytoremediation

sustainable and eco-friendly process that uses plants to clean up contaminated soil, sediment, and water

phytovolatilization

contaminant is taken up from soil and released through stomata

phytodegradation

contaminant is taken up from soil and broken down

phytoaccumulation

contaminant is taken up from soil and concentrated in shoots; plants are harvested and removed from the sight